https://fsunuc.physics.fsu.edu/wiki/api.php?action=feedcontributions&feedformat=atom&user=IwiedenhoeverFSU Fox's Lab Wiki - User contributions [en]2026-04-07T19:28:40ZUser contributionsMediaWiki 1.39.0https://fsunuc.physics.fsu.edu/wiki/index.php?title=Split-Pole_Spectrograph&diff=2396Split-Pole Spectrograph2024-06-20T19:52:42Z<p>Iwiedenhoever: /* Simplification of the z-offset calculation (IW) */</p>
<hr />
<div>[[File:Sideview of the split-pole spectrometer.jpg|none| 800px | Side view of the spilt-pole spectrometer]]<br />
<br />
{| align="right" style="width:30%;"<br />
|-<br />
| [[File:SPS Pictue Annotated.png|thumb|Annotated picture of the SE-SPS, An plain picture is here : [[:File:SPS Magnet.png]]]] || [[File:SPS Picture ray.png|thumb| SE-SPS COSY simulation. An plain picture is here [[:File:SPS Sketch With Cosy.png]]]]<br />
|}<br />
<br />
The '''Super Enge Split-Pole Spectrograph''' <br />
<ref name="Enge1979">H.A. Enge, NIM '''162''', 161 (1979) https://doi.org/10.1016/0029-554X(79)90711-0</ref><br />
<ref>H. A. Enge, NIM '''187''', 1 (1981) https://doi.org/10.1016/0029-554X(81)90465-1 </ref><br />
is a magnet spectrometer to measure the spectrum of nuclear reactions. The concept and design were developed by [https://en.wikipedia.org/wiki/Harald_A._Enge Harald A. Enge]<ref>J. E. Spencer and H. A. Enge, NIM '''49''', 181 (1967) https://doi.org/10.1016/0029-554X(67)90684-2 </ref> at 1967, aimed to have a broad-momentum range spectrograph with <math> p_{max}/p_{min} \approx 2.8 </math> or <math> E_{max}/E_{min} \approx 8 </math>. The spectrometer was originally located at the Wright Nuclear Structure Laboratory (closed at 2013), at Yale University. It was moved to FSU in the fall of 2013. It consists of a reaction chamber, a '''split-pole magnetic spectrograph''', a '''position-sensitive ionization drift chamber''', and a '''plastic scintillator'''. It has an angular acceptance of 128 msr (vertical ±40 mrad, horizontal ±80 mrad). The maximum B-field is 1.63 T with a radius of curvature from 511 mm to 920 mm. The mean radius is 600 mm. The advantage of the split-pole instead of a single-pole magnet is the aberration (x|θ<sup>2</sup>) and (x|φ<sup>2</sup>) are almost zero <ref name="Enge1979" />. <br />
<br />
The '''Super''' Enge Split-Pole Spectrograph is an upgrade of the Yale Enge SPS. The major change is the redesign of the backward silicon detector array to the [[Split-Pole_Spectrograph#SABRE|SABRE]].<br />
<br />
= SPS Experiment Guide =<br />
[[Media:SPS_Experiment_Guide.pdf]]<br />
<br />
= SPS Operating Procedures =<br />
I created this section as a place to store procedures for the chamber swaps, however, I expect there are other things we might want to document here. -p<br />
* [[Target Chamber Swaps]]<br />
<br />
= Online Simulator = <br />
<br />
https://fsunuc.physics.fsu.edu/SPS/<br />
<br />
There was another simulator called [https://github.com/gwm17/websps websps] developed by Gordon. But I am unable to revive it after the server upgraded from Ubuntu 20.04 to Ubuntu 22.04, so I write a new one using javascript. The missing part is the energy loss calculation.<br />
<br />
= Magnet =<br />
[[File:Design of a Split-pole spectrograph.png|thumb|Design of a Split-pole spectrograph. Take from Ref. <ref name="Enge1979"/>]]<br />
<br />
The primary goal of a spectrograph is resolving momentum. A general discussion of magnetic spectrographs can be found at Ref. <ref name="Enge1979" /> and Ref. <ref> H. A. Enge, Physics Today '''20''', 65 (1967) https://doi.org/10.1063/1.3034401 </ref>. There are many designs from a simple single dipole to a combination of multiple dipoles and quadrupoles. <br />
<br />
The SPS magnet was designed for a large solid angle, large resolving power, and correction of kinematic broadening. Using two-directional focusing and second-order focusing spectrograph can achieve a large sold angle and resolving power. Second-order focusing means the second-order terms in the acceptance angles vanish, i.e. no aberration.<br />
<br />
The SPS contains 2 separate poles enveloped by a single coil. The split provides second-order double focusing over a broad range of momenta. The magnet can be rotated from 0 to 55 degrees in the lab. The magnetic field has an upper limit of 1.63 T (or 16.3 kG).<br />
<br />
{| class="wikitable"<br />
|+ This table is taken from B.P. Kay Ph.D thesis (2007)<br />
! Property !! Symbol !! Value<br />
|-<br />
| Orbital radius || <math> \rho </math> || 511 to 920 mm<br />
|-<br />
|Resolving power || <math> p/\Delta p </math> || 1st order of <math> (x|\theta) </math>4290 (at <math>\theta = \pm 80 </math> mrad) <br />
|- <br />
|rowspan="2"| Acceptance || Horizontal || 160 mrad<br />
|-<br />
| Vertical || 80 mrad<br />
|-<br />
| Dispersion || <math> D=(x|\delta) </math> || 1.96<br />
|-<br />
|rowspan="2" | Magnification || <math> M_x = (x|x)</math> || 0.39<br />
|-<br />
| <math> M_y = (y|y)</math> || 2.9<br />
|-<br />
| Maximum field || <math> B </math> || 1.63 T<br />
|}<br />
<br />
== Transfer matrix and COSY INFINITY simulation ==<br />
[[File:Schematics of ion-beam optical element.png|thumb|An illustration of the coordinate of an optical element. This is taken from H.A. Enge NIM 162, 161 (1979).]]<br />
{{Notice | need to fill up. Any 1st few orders transfer matrixes?}}<br />
<br />
The entrance coordinates of the beam are <math> x_1, y_1, \theta_1, \phi_1 </math> wiht momentum <math> \delta = p/p_0 </math>, and coordinate at exit are <math> x_2, y_2, \theta_2, \phi_2 </math>. The entrance and exit coordinates are related by <br />
<br />
<math> x_2 = f_x(x_1, y_1, \theta_1, \phi_1, \delta) </math><br />
<br />
using Taylor expansion:<br />
<br />
<math> \frac{x_2}{\rho} = (x|x) \frac{x_1}{\rho} + (x|\theta) \theta_1 + (x|\delta) \delta + (x|\theta^2) \theta_1^2 + ... </math><br />
<br />
In the above expansion, the term <math> (x|x) </math> is the '''magnification''' in the x-direction. <math> (x|\delta) </math> is the '''dispersion''', and <math> (x|\theta^2) </math> is '''aberration'''. The '''focal plane''' is the z-position that <math> (x|\theta) = 0 </math>, i.e. the exit <math> x_2 </math> does not depend on the entrance angle. <br />
<br />
=== Kinematic broadening ===<br />
[[File:Kinematic correction of spectrometer.png|thumb|Kinematic correction of spectrometer. Taken from H. A. Enge NIM 162, 161 (1979)]]<br />
<br />
Kinematic broadening is the broadening of focus for the same reaction state. After a reaction, the angle and momentum of the recoil particle are related that the entrance angle <math> \theta_1 = f(\delta)</math> is a function of momentum. For each energy state, the relation between the angle and momentum is unique. For example, in a 2-body transfer reaction, the momentum vector is <br />
<br />
<math> ( p_x, p_z ) = ( k \sin(\theta), \gamma \beta \sqrt{m^2-k^2} + \gamma k \cos(\theta) ) </math><br />
<br />
where <math> k, \theta</math> are the momentum and the scattering angle at the CM frame, <math> \gamma, \beta </math> are the Lorentz factor from Lab frame to CM frame, and <math> m </math> is the mass of the particle. All 5 coefficients are constant for a fixed energy state. And the different state is characterized by <math> k </math>. Defined the kinematic factor K:<br />
<br />
<math> K = \frac{1}{p} \frac{dp}{d\theta_1} = \frac{\beta E \sin(\theta)}{ k + \beta \sqrt{m^2 - k^2} \cos(\theta)} </math><br />
<br />
The kinematic broadening can be corrected by shifting the focal plane by <br />
<br />
<math> \Delta z = - D M \rho K, D = (x|\delta), M = (x|x) </math><br />
<br />
= Focal plane detector =<br />
[[File:Focal plane detector.png|400px|thumb|right|Front view of the opened camerabox. The SPS focal plane detector with the front window removed is at the bottom.]]<br />
<br />
[[File:Side Cross section view of the SPS focal plane detector.png|400px|thumb|Side Cross section view of the SPS focal plane detector. Taken from B.P. Kay Ph.D. thesis (2007).]]<br />
<br />
[[File:PID EDE annoteted.png|400px|thumb]]<br />
<br />
{{Notice | The drift ion chamber was repaired in summer 2018 }}<br />
<br />
The focal plane detector <br />
<ref> C. Marshal ''et. al'', IEEE Tran. Inst. and Meas. '''68''', 533 (2018) https://doi.org/10.1109/TIM.2018.2847938</ref><br />
<ref name="Markham1975"> R. G. Markham and R. G. H. Robertson, NIM '''129''', 131 (1975) https://doi.org/10.1016/0029-554X(75)90122-6 </ref><br />
consists of an ion drift chamber with a set of delay lines to detect the position of a particle along the focal plane and a plastic scintillator to detect the energy of the incoming particle. Using the energy loss of the particle through the ion chamber with the energy deposited in the scintillator, particles of different charges and masses can be identified.<br />
<br />
The typical pressure of the drift chamber is 70 to 300 Torr of isobutane gas [HC(CH3)3]. The pressure controls the density of the gas and affects the bias voltage, it further affects the drift velocity.<br />
<br />
{|class='wikitable'<br />
|+ Table of pressure and bias voltages. Data was taken from the Ph.D. thesis of Erin Good (2020)<br />
! Gas pressure (Torr) !! Anode bias (V) !! Cathode plate bias (V) <br />
|-<br />
| 70 || +1050 to +1035 || -550 to -500<br />
|-<br />
| 80 || +1150 || -550<br />
|-<br />
| 100 || +1250 || -600<br />
|-<br />
| 110 || +1200 to 1320 || -620 to -600<br />
|-<br />
| 125 || +1425 || -650<br />
|-<br />
| 130 || +1360 || -725<br />
|-<br />
| 150 || +1500 || -700<br />
|-<br />
|}<br />
<br />
From bottom to top, the cathode plate, drift region (contains four biased field-shaping wire grids), Frisch grid (grounded), three anode wires, and pickup pads (which are with the delay lines). Electrons induced by any radiation will drift upward, pass the Frisch grid, are accelerated by the anodes, and hit the pickup pads. The pickup pads are strips with 45° against the anode wires, almost parallel to the particle trajectories<ref name="Markham1975" />. Each pickup strip is 0.09" (2.286 mm) wide and 1.4" (35.56 mm) long, and spaced 0.01" (0.245 mm). A total of 440 lead-coated copper strips with a 5 ns delay per strip results in a nominal total delay of 2.2 μs. Every 10 strips share a delay chip. The position of the hit position can then be determined by the time difference at the end of the delay line.<br />
<br />
There are two position-sensitive delay lines (separated by 42.8625 mm) in the focal plane detector. By reconstructing the particle trajectory using the position information of both delay lines, the resolution can be enhanced by correcting for the kinematic shift of the reaction.<br />
<br />
After passing the drift chamber, the particles will be stopped and detected in a plastic scintillator with a photomultiplier tube (PMT) at each end. Together with the energy loss, obtained by the cathode in the drift chamber, a ΔE-E particle identification can be done.<br />
<br />
<br />
== Outline of the algorithm ==<br />
<br />
There are 9 readouts channels from the focal plane detector: <br />
{| class="wikitable"<br />
! readout !! type of signal <br />
|-<br />
| cathode || energy loss<br />
|-<br />
| Front delay line Left || timing<br />
|-<br />
| Front delay line Right || timing<br />
|-<br />
| Front anode || energy loss<br />
|-<br />
| Rear delay line Left || timing<br />
|-<br />
| Rear delay line Right || timing<br />
|-<br />
| Rear anode || energy loss<br />
|-<br />
| PMT Left || energy loss<br />
|-<br />
| PMT Right || energy loss<br />
|}<br />
<br />
The PID is usually using one of the PMT energy and either the cathode or anode energy. <br />
<br />
The coordinate at the Focal Plane is the conventional one, where z-axis is perpendicular to the focal plane detector, y-axis is the vertical, and x-axis is the z-axis cross y-axis. The positions of the front and Rear planes are constructed by the timestamp. Suppose the timestamp is in ns. <br />
<br />
<math> <br />
x_1 = \frac{t_{FL} - t_{FR}}{2} \frac{1}{2.1} ; ~~~ x_2 = \frac{t_{BL} - t_{BR}}{2} \frac{1}{1.98}<br />
</math><br />
<br />
The position at the center of the focal plane is <br />
<br />
<math><br />
x_{avg} = x_1 + x_2 <br />
</math><br />
<br />
However, for different reactions, there is a z-offset, so that the focal plane is shifted<br />
<br />
<math><br />
x_{avg} = \left(\frac{1}{2} - \frac{z_{o}}{D} \right) x_1 + \left(\frac{1}{2} + \frac{z_{o}}{D} \right) x_2 <br />
</math><br />
<br />
where <math> D = 42.8625~[\textrm{mm}] </math> is the distance between the front and rear delay lines.<br />
<br />
=== Calculation of the z-offset ===<br />
<br />
The z-offset depends on the reaction, the angle <math> \theta </math>, and the magnetic field of the spilt-pole. Suppose we know the KE <math> T_b </math> and momentum <math> P </math> of the ejectile or the interested particle that goes into the split-pole, The reaction is denoted as A(a,b)B, where a is the beam (projectile), A is the target, B is the heavy recoil (residual),and b is the recoil (ejectile).<br />
<br />
<math> P^2 = (m_b+T_b)^2 - m_b^2 = T_b(T_b + 2m_b)~[\textrm{MeV/c}^2]</math><br />
<br />
<math> \rho = \frac{P}{c Z B}~[\textrm{m}] </math>, where <math> c = 299.792458 </math>, <math>Z</math> is the charge number, and <math>B</math> is the magnetic field in Tesla.<br />
<br />
<math> k = \frac{v \sin(\theta)}{ m_b + m_B - v \cos(\theta)},~~~ v = \sqrt{\frac{m_a m_B T_a}{T_b}}</math><br />
<br />
<math> z_o = -\rho \delta_x M_x k [\textrm{m}]</math><br />
<br />
where <math> \delta_x = 1.96 </math> is the x-dispersion and <math> M_x = 0.39</math> is the x-magnification.<br />
<br />
=== Simplification of the z-offset calculation (IW) ===<br />
<br />
The Kinematic Factor k can be re-written as a function of the beam and ejectile momenta: <br />
<br />
<math> k = \frac{(p_a/p_b) \sin(\theta)}{ 1 + m_B/m_b - (p_a/p_b) \cos(\theta)} </math><br />
<br />
Inserting that into the offset formula and using <math> p_b = B \rho q_b </math> gives<br />
<br />
<math> z_o = - \delta_x M_x \frac{(p_a/B q_b) \sin(\theta) }{ 1 + m_B/m_b - (p_a/(B \rho q_b)) \cos(\theta)} </math>,<br />
<br />
which only depends on the beam momentum and masses and the spectrograph B and <math> \theta </math>. <br />
The second order correction (tilt of focal plane) is included in the denominator through the <math> \rho </math> dependence.<br />
<br />
== Kinematic correction of the focal plane == <br />
<br />
As pointed out before, the [[Split-Pole_Spectrograph#Kinematic_broadening | kinematic broadening]] can be corrected. In SPS, the dispersion D is 1.96, magnification is 0.39. <br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:AnnotatedFocalPlaneRay.png | 400px|frameless| ]] <br />
| style="width: 400px;"| [[File:FPShift.gif|frame|]]<br />
|-<br />
|Simulated rays near the focal plane. || An animation on the shift of the focal panel. An optimum is reached at FP = -42 mm.<br />
|}<br />
<br />
[[File:XavgDiagram.png|thumb| construction of Xavg (X-average) on the virtual focal plan (a liner plane in this case). Need to redraw the picture, the Y-axis should be Z-axis, and it should be rotated 180 degree, so the particle is from bottom to top.]]<br />
A parallel shift of the focal plane maybe not be enough. Suppose the best focal plan is given by a function <math> z = f(x) </math>. The 2 positions extracted from the front and rear delay lines are <math> x_1, x_2 </math>, and the distance between the front and rear delay lines is <math> d</math>. The X-avg is the solution of the equation:<br />
<br />
<math> f(x) = \frac{x_2 - x_1}{d} \left( x - \frac{x_2 + x_1}{2} \right) </math><br />
<br />
For a linear tilted plane <math> f(x) = m x + z_0 </math>, the X-avg is <br />
<br />
<math> X_{avg} = \frac{x_1^2 - x_2^2 - 2d z_0 }{2 (d m + x_1 - x_2) } </math><br />
<br />
<br />
<!--[[File:TwoBodyKinematics.png|thumb]]--><br />
<br />
= SABRE =<br />
<br />
[[File:SABER installing particle shield.png|thumb|right|Installing particle shield on SABRE (photo taken on May 5, 2022)]]<br />
<br />
SABRE is a '''S'''ilicon '''A'''rray for '''B'''ranching '''R'''atio '''E'''xperiments <br />
<ref> E. C. Good ''et. al'', NIM A '''1003''', 165299 (2021) https://www.sciencedirect.com/science/article/pii/S0168900221002837</ref> <br />
with the SPS. Its predecessor is the Yale Lamp Shade Array (YLSA). SABRE sits at backward angles from the target and covers roughly 30% of 4π. SABRE has both thick and thin dead-layer detectors, with the thin dead-layer detectors capable of reaching ~200 keV thresholds for protons and deuterons.<br />
<br />
= CeBrA =<br />
<br />
[[File:CeBrA array diagram.png|thumb| Solid Works drawing of the fully planned array, which will consist of 13 CeBr<sub>3</sub> detectors.]]<br />
<br />
The Cerium Bromide Array (CeBrA) <ref> A. L. Conley ''et al.'', NIM A '''1058''' (2023) 168827 https://doi.org/10.1016/j.nima.2023.168827 </ref> is a γ-ray detector array designed to be used in conjunction with the SE-SPS. Comprised of low-background CeBr<sub>3</sub> scintillators with Hamamatsu photomultipliers. There are currently 7 commissioned detectors in the array with varying size crystals (2-1x1 inch, 4-2x2 inch, and 1-3x4 inch crystal detectors; a schematic for the full array on is shown on the right). The goal of CeBrA is to establish coincident events with the light-ions detected in the focal plane detector of the SE-SPS and the corresponding γ-rays from the excited recoiling nucleus, which are called particle-gamma coincidences. The scattering chamber used for CeBrA differs from the usual sliding-seal chamber that is used with the SE-SPS. With a hemisphere shape, it sits at a fixed 35<sup>o</sup> angle relative to the SE-SPS and allows for a more detailed study of the electromagnetic transitions from nuclei excited in reactions using the SE-SPS.<br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:Current_array.jpg | 400px|frameless|]] <br />
|-<br />
|Current array setup for CeBrA as it was used in the Summer 2023 REU experiments studying the <sup>52</sup>Cr(d,pγ)<sup>53</sup>Cr and <sup>34</sup>S(d,pγ)<sup>35</sup>S reactions, which was a follow up from the previous REU from 2022.<br />
|}<br />
<br />
= Repositories =<br />
https://github.com/sesps<br />
<br />
= Contact =<br />
* Jeff Blackmon mailto:blackmon@lsu.edu<br />
* Mark-Christoph Spieker mailto:mspieker@fsu.edu<br />
* Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
* <span style=color:red">who should be contacted? </span><br />
<br />
= References =</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Split-Pole_Spectrograph&diff=2395Split-Pole Spectrograph2024-06-20T19:49:14Z<p>Iwiedenhoever: /* Simplification of the z-offset calculation (IW) */</p>
<hr />
<div>[[File:Sideview of the split-pole spectrometer.jpg|none| 800px | Side view of the spilt-pole spectrometer]]<br />
<br />
{| align="right" style="width:30%;"<br />
|-<br />
| [[File:SPS Pictue Annotated.png|thumb|Annotated picture of the SE-SPS, An plain picture is here : [[:File:SPS Magnet.png]]]] || [[File:SPS Picture ray.png|thumb| SE-SPS COSY simulation. An plain picture is here [[:File:SPS Sketch With Cosy.png]]]]<br />
|}<br />
<br />
The '''Super Enge Split-Pole Spectrograph''' <br />
<ref name="Enge1979">H.A. Enge, NIM '''162''', 161 (1979) https://doi.org/10.1016/0029-554X(79)90711-0</ref><br />
<ref>H. A. Enge, NIM '''187''', 1 (1981) https://doi.org/10.1016/0029-554X(81)90465-1 </ref><br />
is a magnet spectrometer to measure the spectrum of nuclear reactions. The concept and design were developed by [https://en.wikipedia.org/wiki/Harald_A._Enge Harald A. Enge]<ref>J. E. Spencer and H. A. Enge, NIM '''49''', 181 (1967) https://doi.org/10.1016/0029-554X(67)90684-2 </ref> at 1967, aimed to have a broad-momentum range spectrograph with <math> p_{max}/p_{min} \approx 2.8 </math> or <math> E_{max}/E_{min} \approx 8 </math>. The spectrometer was originally located at the Wright Nuclear Structure Laboratory (closed at 2013), at Yale University. It was moved to FSU in the fall of 2013. It consists of a reaction chamber, a '''split-pole magnetic spectrograph''', a '''position-sensitive ionization drift chamber''', and a '''plastic scintillator'''. It has an angular acceptance of 128 msr (vertical ±40 mrad, horizontal ±80 mrad). The maximum B-field is 1.63 T with a radius of curvature from 511 mm to 920 mm. The mean radius is 600 mm. The advantage of the split-pole instead of a single-pole magnet is the aberration (x|θ<sup>2</sup>) and (x|φ<sup>2</sup>) are almost zero <ref name="Enge1979" />. <br />
<br />
The '''Super''' Enge Split-Pole Spectrograph is an upgrade of the Yale Enge SPS. The major change is the redesign of the backward silicon detector array to the [[Split-Pole_Spectrograph#SABRE|SABRE]].<br />
<br />
= SPS Experiment Guide =<br />
[[Media:SPS_Experiment_Guide.pdf]]<br />
<br />
= SPS Operating Procedures =<br />
I created this section as a place to store procedures for the chamber swaps, however, I expect there are other things we might want to document here. -p<br />
* [[Target Chamber Swaps]]<br />
<br />
= Online Simulator = <br />
<br />
https://fsunuc.physics.fsu.edu/SPS/<br />
<br />
There was another simulator called [https://github.com/gwm17/websps websps] developed by Gordon. But I am unable to revive it after the server upgraded from Ubuntu 20.04 to Ubuntu 22.04, so I write a new one using javascript. The missing part is the energy loss calculation.<br />
<br />
= Magnet =<br />
[[File:Design of a Split-pole spectrograph.png|thumb|Design of a Split-pole spectrograph. Take from Ref. <ref name="Enge1979"/>]]<br />
<br />
The primary goal of a spectrograph is resolving momentum. A general discussion of magnetic spectrographs can be found at Ref. <ref name="Enge1979" /> and Ref. <ref> H. A. Enge, Physics Today '''20''', 65 (1967) https://doi.org/10.1063/1.3034401 </ref>. There are many designs from a simple single dipole to a combination of multiple dipoles and quadrupoles. <br />
<br />
The SPS magnet was designed for a large solid angle, large resolving power, and correction of kinematic broadening. Using two-directional focusing and second-order focusing spectrograph can achieve a large sold angle and resolving power. Second-order focusing means the second-order terms in the acceptance angles vanish, i.e. no aberration.<br />
<br />
The SPS contains 2 separate poles enveloped by a single coil. The split provides second-order double focusing over a broad range of momenta. The magnet can be rotated from 0 to 55 degrees in the lab. The magnetic field has an upper limit of 1.63 T (or 16.3 kG).<br />
<br />
{| class="wikitable"<br />
|+ This table is taken from B.P. Kay Ph.D thesis (2007)<br />
! Property !! Symbol !! Value<br />
|-<br />
| Orbital radius || <math> \rho </math> || 511 to 920 mm<br />
|-<br />
|Resolving power || <math> p/\Delta p </math> || 1st order of <math> (x|\theta) </math>4290 (at <math>\theta = \pm 80 </math> mrad) <br />
|- <br />
|rowspan="2"| Acceptance || Horizontal || 160 mrad<br />
|-<br />
| Vertical || 80 mrad<br />
|-<br />
| Dispersion || <math> D=(x|\delta) </math> || 1.96<br />
|-<br />
|rowspan="2" | Magnification || <math> M_x = (x|x)</math> || 0.39<br />
|-<br />
| <math> M_y = (y|y)</math> || 2.9<br />
|-<br />
| Maximum field || <math> B </math> || 1.63 T<br />
|}<br />
<br />
== Transfer matrix and COSY INFINITY simulation ==<br />
[[File:Schematics of ion-beam optical element.png|thumb|An illustration of the coordinate of an optical element. This is taken from H.A. Enge NIM 162, 161 (1979).]]<br />
{{Notice | need to fill up. Any 1st few orders transfer matrixes?}}<br />
<br />
The entrance coordinates of the beam are <math> x_1, y_1, \theta_1, \phi_1 </math> wiht momentum <math> \delta = p/p_0 </math>, and coordinate at exit are <math> x_2, y_2, \theta_2, \phi_2 </math>. The entrance and exit coordinates are related by <br />
<br />
<math> x_2 = f_x(x_1, y_1, \theta_1, \phi_1, \delta) </math><br />
<br />
using Taylor expansion:<br />
<br />
<math> \frac{x_2}{\rho} = (x|x) \frac{x_1}{\rho} + (x|\theta) \theta_1 + (x|\delta) \delta + (x|\theta^2) \theta_1^2 + ... </math><br />
<br />
In the above expansion, the term <math> (x|x) </math> is the '''magnification''' in the x-direction. <math> (x|\delta) </math> is the '''dispersion''', and <math> (x|\theta^2) </math> is '''aberration'''. The '''focal plane''' is the z-position that <math> (x|\theta) = 0 </math>, i.e. the exit <math> x_2 </math> does not depend on the entrance angle. <br />
<br />
=== Kinematic broadening ===<br />
[[File:Kinematic correction of spectrometer.png|thumb|Kinematic correction of spectrometer. Taken from H. A. Enge NIM 162, 161 (1979)]]<br />
<br />
Kinematic broadening is the broadening of focus for the same reaction state. After a reaction, the angle and momentum of the recoil particle are related that the entrance angle <math> \theta_1 = f(\delta)</math> is a function of momentum. For each energy state, the relation between the angle and momentum is unique. For example, in a 2-body transfer reaction, the momentum vector is <br />
<br />
<math> ( p_x, p_z ) = ( k \sin(\theta), \gamma \beta \sqrt{m^2-k^2} + \gamma k \cos(\theta) ) </math><br />
<br />
where <math> k, \theta</math> are the momentum and the scattering angle at the CM frame, <math> \gamma, \beta </math> are the Lorentz factor from Lab frame to CM frame, and <math> m </math> is the mass of the particle. All 5 coefficients are constant for a fixed energy state. And the different state is characterized by <math> k </math>. Defined the kinematic factor K:<br />
<br />
<math> K = \frac{1}{p} \frac{dp}{d\theta_1} = \frac{\beta E \sin(\theta)}{ k + \beta \sqrt{m^2 - k^2} \cos(\theta)} </math><br />
<br />
The kinematic broadening can be corrected by shifting the focal plane by <br />
<br />
<math> \Delta z = - D M \rho K, D = (x|\delta), M = (x|x) </math><br />
<br />
= Focal plane detector =<br />
[[File:Focal plane detector.png|400px|thumb|right|Front view of the opened camerabox. The SPS focal plane detector with the front window removed is at the bottom.]]<br />
<br />
[[File:Side Cross section view of the SPS focal plane detector.png|400px|thumb|Side Cross section view of the SPS focal plane detector. Taken from B.P. Kay Ph.D. thesis (2007).]]<br />
<br />
[[File:PID EDE annoteted.png|400px|thumb]]<br />
<br />
{{Notice | The drift ion chamber was repaired in summer 2018 }}<br />
<br />
The focal plane detector <br />
<ref> C. Marshal ''et. al'', IEEE Tran. Inst. and Meas. '''68''', 533 (2018) https://doi.org/10.1109/TIM.2018.2847938</ref><br />
<ref name="Markham1975"> R. G. Markham and R. G. H. Robertson, NIM '''129''', 131 (1975) https://doi.org/10.1016/0029-554X(75)90122-6 </ref><br />
consists of an ion drift chamber with a set of delay lines to detect the position of a particle along the focal plane and a plastic scintillator to detect the energy of the incoming particle. Using the energy loss of the particle through the ion chamber with the energy deposited in the scintillator, particles of different charges and masses can be identified.<br />
<br />
The typical pressure of the drift chamber is 70 to 300 Torr of isobutane gas [HC(CH3)3]. The pressure controls the density of the gas and affects the bias voltage, it further affects the drift velocity.<br />
<br />
{|class='wikitable'<br />
|+ Table of pressure and bias voltages. Data was taken from the Ph.D. thesis of Erin Good (2020)<br />
! Gas pressure (Torr) !! Anode bias (V) !! Cathode plate bias (V) <br />
|-<br />
| 70 || +1050 to +1035 || -550 to -500<br />
|-<br />
| 80 || +1150 || -550<br />
|-<br />
| 100 || +1250 || -600<br />
|-<br />
| 110 || +1200 to 1320 || -620 to -600<br />
|-<br />
| 125 || +1425 || -650<br />
|-<br />
| 130 || +1360 || -725<br />
|-<br />
| 150 || +1500 || -700<br />
|-<br />
|}<br />
<br />
From bottom to top, the cathode plate, drift region (contains four biased field-shaping wire grids), Frisch grid (grounded), three anode wires, and pickup pads (which are with the delay lines). Electrons induced by any radiation will drift upward, pass the Frisch grid, are accelerated by the anodes, and hit the pickup pads. The pickup pads are strips with 45° against the anode wires, almost parallel to the particle trajectories<ref name="Markham1975" />. Each pickup strip is 0.09" (2.286 mm) wide and 1.4" (35.56 mm) long, and spaced 0.01" (0.245 mm). A total of 440 lead-coated copper strips with a 5 ns delay per strip results in a nominal total delay of 2.2 μs. Every 10 strips share a delay chip. The position of the hit position can then be determined by the time difference at the end of the delay line.<br />
<br />
There are two position-sensitive delay lines (separated by 42.8625 mm) in the focal plane detector. By reconstructing the particle trajectory using the position information of both delay lines, the resolution can be enhanced by correcting for the kinematic shift of the reaction.<br />
<br />
After passing the drift chamber, the particles will be stopped and detected in a plastic scintillator with a photomultiplier tube (PMT) at each end. Together with the energy loss, obtained by the cathode in the drift chamber, a ΔE-E particle identification can be done.<br />
<br />
<br />
== Outline of the algorithm ==<br />
<br />
There are 9 readouts channels from the focal plane detector: <br />
{| class="wikitable"<br />
! readout !! type of signal <br />
|-<br />
| cathode || energy loss<br />
|-<br />
| Front delay line Left || timing<br />
|-<br />
| Front delay line Right || timing<br />
|-<br />
| Front anode || energy loss<br />
|-<br />
| Rear delay line Left || timing<br />
|-<br />
| Rear delay line Right || timing<br />
|-<br />
| Rear anode || energy loss<br />
|-<br />
| PMT Left || energy loss<br />
|-<br />
| PMT Right || energy loss<br />
|}<br />
<br />
The PID is usually using one of the PMT energy and either the cathode or anode energy. <br />
<br />
The coordinate at the Focal Plane is the conventional one, where z-axis is perpendicular to the focal plane detector, y-axis is the vertical, and x-axis is the z-axis cross y-axis. The positions of the front and Rear planes are constructed by the timestamp. Suppose the timestamp is in ns. <br />
<br />
<math> <br />
x_1 = \frac{t_{FL} - t_{FR}}{2} \frac{1}{2.1} ; ~~~ x_2 = \frac{t_{BL} - t_{BR}}{2} \frac{1}{1.98}<br />
</math><br />
<br />
The position at the center of the focal plane is <br />
<br />
<math><br />
x_{avg} = x_1 + x_2 <br />
</math><br />
<br />
However, for different reactions, there is a z-offset, so that the focal plane is shifted<br />
<br />
<math><br />
x_{avg} = \left(\frac{1}{2} - \frac{z_{o}}{D} \right) x_1 + \left(\frac{1}{2} + \frac{z_{o}}{D} \right) x_2 <br />
</math><br />
<br />
where <math> D = 42.8625~[\textrm{mm}] </math> is the distance between the front and rear delay lines.<br />
<br />
=== Calculation of the z-offset ===<br />
<br />
The z-offset depends on the reaction, the angle <math> \theta </math>, and the magnetic field of the spilt-pole. Suppose we know the KE <math> T_b </math> and momentum <math> P </math> of the ejectile or the interested particle that goes into the split-pole, The reaction is denoted as A(a,b)B, where a is the beam (projectile), A is the target, B is the heavy recoil (residual),and b is the recoil (ejectile).<br />
<br />
<math> P^2 = (m_b+T_b)^2 - m_b^2 = T_b(T_b + 2m_b)~[\textrm{MeV/c}^2]</math><br />
<br />
<math> \rho = \frac{P}{c Z B}~[\textrm{m}] </math>, where <math> c = 299.792458 </math>, <math>Z</math> is the charge number, and <math>B</math> is the magnetic field in Tesla.<br />
<br />
<math> k = \frac{v \sin(\theta)}{ m_b + m_B - v \cos(\theta)},~~~ v = \sqrt{\frac{m_a m_B T_a}{T_b}}</math><br />
<br />
<math> z_o = -\rho \delta_x M_x k [\textrm{m}]</math><br />
<br />
where <math> \delta_x = 1.96 </math> is the x-dispersion and <math> M_x = 0.39</math> is the x-magnification.<br />
<br />
=== Simplification of the z-offset calculation (IW) ===<br />
<br />
The Kinematic Factor k can be re-written as a function of the beam and ejectile momenta: <br />
<br />
<math> k = \frac{(p_a/p_b) \sin(\theta)}{ 1 + m_B/m_b - (p_a/p_b) \cos(\theta)} </math><br />
<br />
Inserting that into the offset formula and using <math> p_b = B \rho q_b </math> gives<br />
<br />
<math> z_o = - \delta_x M_x \frac{(p_a/B q_b) \sin(\theta) }{ 1 + m_B/m_b - (p_a/(B \rho q_b)) \cos(\theta)} </math>,<br />
<br />
which only depends on the beam momentum and masses and the spectrograph B, theta. <br />
The second order correction (tilt of focal plane) is included in the denominator through the <math> \rho <\math> dependence.<br />
<br />
== Kinematic correction of the focal plane == <br />
<br />
As pointed out before, the [[Split-Pole_Spectrograph#Kinematic_broadening | kinematic broadening]] can be corrected. In SPS, the dispersion D is 1.96, magnification is 0.39. <br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:AnnotatedFocalPlaneRay.png | 400px|frameless| ]] <br />
| style="width: 400px;"| [[File:FPShift.gif|frame|]]<br />
|-<br />
|Simulated rays near the focal plane. || An animation on the shift of the focal panel. An optimum is reached at FP = -42 mm.<br />
|}<br />
<br />
[[File:XavgDiagram.png|thumb| construction of Xavg (X-average) on the virtual focal plan (a liner plane in this case). Need to redraw the picture, the Y-axis should be Z-axis, and it should be rotated 180 degree, so the particle is from bottom to top.]]<br />
A parallel shift of the focal plane maybe not be enough. Suppose the best focal plan is given by a function <math> z = f(x) </math>. The 2 positions extracted from the front and rear delay lines are <math> x_1, x_2 </math>, and the distance between the front and rear delay lines is <math> d</math>. The X-avg is the solution of the equation:<br />
<br />
<math> f(x) = \frac{x_2 - x_1}{d} \left( x - \frac{x_2 + x_1}{2} \right) </math><br />
<br />
For a linear tilted plane <math> f(x) = m x + z_0 </math>, the X-avg is <br />
<br />
<math> X_{avg} = \frac{x_1^2 - x_2^2 - 2d z_0 }{2 (d m + x_1 - x_2) } </math><br />
<br />
<br />
<!--[[File:TwoBodyKinematics.png|thumb]]--><br />
<br />
= SABRE =<br />
<br />
[[File:SABER installing particle shield.png|thumb|right|Installing particle shield on SABRE (photo taken on May 5, 2022)]]<br />
<br />
SABRE is a '''S'''ilicon '''A'''rray for '''B'''ranching '''R'''atio '''E'''xperiments <br />
<ref> E. C. Good ''et. al'', NIM A '''1003''', 165299 (2021) https://www.sciencedirect.com/science/article/pii/S0168900221002837</ref> <br />
with the SPS. Its predecessor is the Yale Lamp Shade Array (YLSA). SABRE sits at backward angles from the target and covers roughly 30% of 4π. SABRE has both thick and thin dead-layer detectors, with the thin dead-layer detectors capable of reaching ~200 keV thresholds for protons and deuterons.<br />
<br />
= CeBrA =<br />
<br />
[[File:CeBrA array diagram.png|thumb| Solid Works drawing of the fully planned array, which will consist of 13 CeBr<sub>3</sub> detectors.]]<br />
<br />
The Cerium Bromide Array (CeBrA) <ref> A. L. Conley ''et al.'', NIM A '''1058''' (2023) 168827 https://doi.org/10.1016/j.nima.2023.168827 </ref> is a γ-ray detector array designed to be used in conjunction with the SE-SPS. Comprised of low-background CeBr<sub>3</sub> scintillators with Hamamatsu photomultipliers. There are currently 7 commissioned detectors in the array with varying size crystals (2-1x1 inch, 4-2x2 inch, and 1-3x4 inch crystal detectors; a schematic for the full array on is shown on the right). The goal of CeBrA is to establish coincident events with the light-ions detected in the focal plane detector of the SE-SPS and the corresponding γ-rays from the excited recoiling nucleus, which are called particle-gamma coincidences. The scattering chamber used for CeBrA differs from the usual sliding-seal chamber that is used with the SE-SPS. With a hemisphere shape, it sits at a fixed 35<sup>o</sup> angle relative to the SE-SPS and allows for a more detailed study of the electromagnetic transitions from nuclei excited in reactions using the SE-SPS.<br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:Current_array.jpg | 400px|frameless|]] <br />
|-<br />
|Current array setup for CeBrA as it was used in the Summer 2023 REU experiments studying the <sup>52</sup>Cr(d,pγ)<sup>53</sup>Cr and <sup>34</sup>S(d,pγ)<sup>35</sup>S reactions, which was a follow up from the previous REU from 2022.<br />
|}<br />
<br />
= Repositories =<br />
https://github.com/sesps<br />
<br />
= Contact =<br />
* Jeff Blackmon mailto:blackmon@lsu.edu<br />
* Mark-Christoph Spieker mailto:mspieker@fsu.edu<br />
* Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
* <span style=color:red">who should be contacted? </span><br />
<br />
= References =</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Split-Pole_Spectrograph&diff=2394Split-Pole Spectrograph2024-06-20T19:44:53Z<p>Iwiedenhoever: /* Simplification of the z-offset calculation (IW) */</p>
<hr />
<div>[[File:Sideview of the split-pole spectrometer.jpg|none| 800px | Side view of the spilt-pole spectrometer]]<br />
<br />
{| align="right" style="width:30%;"<br />
|-<br />
| [[File:SPS Pictue Annotated.png|thumb|Annotated picture of the SE-SPS, An plain picture is here : [[:File:SPS Magnet.png]]]] || [[File:SPS Picture ray.png|thumb| SE-SPS COSY simulation. An plain picture is here [[:File:SPS Sketch With Cosy.png]]]]<br />
|}<br />
<br />
The '''Super Enge Split-Pole Spectrograph''' <br />
<ref name="Enge1979">H.A. Enge, NIM '''162''', 161 (1979) https://doi.org/10.1016/0029-554X(79)90711-0</ref><br />
<ref>H. A. Enge, NIM '''187''', 1 (1981) https://doi.org/10.1016/0029-554X(81)90465-1 </ref><br />
is a magnet spectrometer to measure the spectrum of nuclear reactions. The concept and design were developed by [https://en.wikipedia.org/wiki/Harald_A._Enge Harald A. Enge]<ref>J. E. Spencer and H. A. Enge, NIM '''49''', 181 (1967) https://doi.org/10.1016/0029-554X(67)90684-2 </ref> at 1967, aimed to have a broad-momentum range spectrograph with <math> p_{max}/p_{min} \approx 2.8 </math> or <math> E_{max}/E_{min} \approx 8 </math>. The spectrometer was originally located at the Wright Nuclear Structure Laboratory (closed at 2013), at Yale University. It was moved to FSU in the fall of 2013. It consists of a reaction chamber, a '''split-pole magnetic spectrograph''', a '''position-sensitive ionization drift chamber''', and a '''plastic scintillator'''. It has an angular acceptance of 128 msr (vertical ±40 mrad, horizontal ±80 mrad). The maximum B-field is 1.63 T with a radius of curvature from 511 mm to 920 mm. The mean radius is 600 mm. The advantage of the split-pole instead of a single-pole magnet is the aberration (x|θ<sup>2</sup>) and (x|φ<sup>2</sup>) are almost zero <ref name="Enge1979" />. <br />
<br />
The '''Super''' Enge Split-Pole Spectrograph is an upgrade of the Yale Enge SPS. The major change is the redesign of the backward silicon detector array to the [[Split-Pole_Spectrograph#SABRE|SABRE]].<br />
<br />
= SPS Experiment Guide =<br />
[[Media:SPS_Experiment_Guide.pdf]]<br />
<br />
= SPS Operating Procedures =<br />
I created this section as a place to store procedures for the chamber swaps, however, I expect there are other things we might want to document here. -p<br />
* [[Target Chamber Swaps]]<br />
<br />
= Online Simulator = <br />
<br />
https://fsunuc.physics.fsu.edu/SPS/<br />
<br />
There was another simulator called [https://github.com/gwm17/websps websps] developed by Gordon. But I am unable to revive it after the server upgraded from Ubuntu 20.04 to Ubuntu 22.04, so I write a new one using javascript. The missing part is the energy loss calculation.<br />
<br />
= Magnet =<br />
[[File:Design of a Split-pole spectrograph.png|thumb|Design of a Split-pole spectrograph. Take from Ref. <ref name="Enge1979"/>]]<br />
<br />
The primary goal of a spectrograph is resolving momentum. A general discussion of magnetic spectrographs can be found at Ref. <ref name="Enge1979" /> and Ref. <ref> H. A. Enge, Physics Today '''20''', 65 (1967) https://doi.org/10.1063/1.3034401 </ref>. There are many designs from a simple single dipole to a combination of multiple dipoles and quadrupoles. <br />
<br />
The SPS magnet was designed for a large solid angle, large resolving power, and correction of kinematic broadening. Using two-directional focusing and second-order focusing spectrograph can achieve a large sold angle and resolving power. Second-order focusing means the second-order terms in the acceptance angles vanish, i.e. no aberration.<br />
<br />
The SPS contains 2 separate poles enveloped by a single coil. The split provides second-order double focusing over a broad range of momenta. The magnet can be rotated from 0 to 55 degrees in the lab. The magnetic field has an upper limit of 1.63 T (or 16.3 kG).<br />
<br />
{| class="wikitable"<br />
|+ This table is taken from B.P. Kay Ph.D thesis (2007)<br />
! Property !! Symbol !! Value<br />
|-<br />
| Orbital radius || <math> \rho </math> || 511 to 920 mm<br />
|-<br />
|Resolving power || <math> p/\Delta p </math> || 1st order of <math> (x|\theta) </math>4290 (at <math>\theta = \pm 80 </math> mrad) <br />
|- <br />
|rowspan="2"| Acceptance || Horizontal || 160 mrad<br />
|-<br />
| Vertical || 80 mrad<br />
|-<br />
| Dispersion || <math> D=(x|\delta) </math> || 1.96<br />
|-<br />
|rowspan="2" | Magnification || <math> M_x = (x|x)</math> || 0.39<br />
|-<br />
| <math> M_y = (y|y)</math> || 2.9<br />
|-<br />
| Maximum field || <math> B </math> || 1.63 T<br />
|}<br />
<br />
== Transfer matrix and COSY INFINITY simulation ==<br />
[[File:Schematics of ion-beam optical element.png|thumb|An illustration of the coordinate of an optical element. This is taken from H.A. Enge NIM 162, 161 (1979).]]<br />
{{Notice | need to fill up. Any 1st few orders transfer matrixes?}}<br />
<br />
The entrance coordinates of the beam are <math> x_1, y_1, \theta_1, \phi_1 </math> wiht momentum <math> \delta = p/p_0 </math>, and coordinate at exit are <math> x_2, y_2, \theta_2, \phi_2 </math>. The entrance and exit coordinates are related by <br />
<br />
<math> x_2 = f_x(x_1, y_1, \theta_1, \phi_1, \delta) </math><br />
<br />
using Taylor expansion:<br />
<br />
<math> \frac{x_2}{\rho} = (x|x) \frac{x_1}{\rho} + (x|\theta) \theta_1 + (x|\delta) \delta + (x|\theta^2) \theta_1^2 + ... </math><br />
<br />
In the above expansion, the term <math> (x|x) </math> is the '''magnification''' in the x-direction. <math> (x|\delta) </math> is the '''dispersion''', and <math> (x|\theta^2) </math> is '''aberration'''. The '''focal plane''' is the z-position that <math> (x|\theta) = 0 </math>, i.e. the exit <math> x_2 </math> does not depend on the entrance angle. <br />
<br />
=== Kinematic broadening ===<br />
[[File:Kinematic correction of spectrometer.png|thumb|Kinematic correction of spectrometer. Taken from H. A. Enge NIM 162, 161 (1979)]]<br />
<br />
Kinematic broadening is the broadening of focus for the same reaction state. After a reaction, the angle and momentum of the recoil particle are related that the entrance angle <math> \theta_1 = f(\delta)</math> is a function of momentum. For each energy state, the relation between the angle and momentum is unique. For example, in a 2-body transfer reaction, the momentum vector is <br />
<br />
<math> ( p_x, p_z ) = ( k \sin(\theta), \gamma \beta \sqrt{m^2-k^2} + \gamma k \cos(\theta) ) </math><br />
<br />
where <math> k, \theta</math> are the momentum and the scattering angle at the CM frame, <math> \gamma, \beta </math> are the Lorentz factor from Lab frame to CM frame, and <math> m </math> is the mass of the particle. All 5 coefficients are constant for a fixed energy state. And the different state is characterized by <math> k </math>. Defined the kinematic factor K:<br />
<br />
<math> K = \frac{1}{p} \frac{dp}{d\theta_1} = \frac{\beta E \sin(\theta)}{ k + \beta \sqrt{m^2 - k^2} \cos(\theta)} </math><br />
<br />
The kinematic broadening can be corrected by shifting the focal plane by <br />
<br />
<math> \Delta z = - D M \rho K, D = (x|\delta), M = (x|x) </math><br />
<br />
= Focal plane detector =<br />
[[File:Focal plane detector.png|400px|thumb|right|Front view of the opened camerabox. The SPS focal plane detector with the front window removed is at the bottom.]]<br />
<br />
[[File:Side Cross section view of the SPS focal plane detector.png|400px|thumb|Side Cross section view of the SPS focal plane detector. Taken from B.P. Kay Ph.D. thesis (2007).]]<br />
<br />
[[File:PID EDE annoteted.png|400px|thumb]]<br />
<br />
{{Notice | The drift ion chamber was repaired in summer 2018 }}<br />
<br />
The focal plane detector <br />
<ref> C. Marshal ''et. al'', IEEE Tran. Inst. and Meas. '''68''', 533 (2018) https://doi.org/10.1109/TIM.2018.2847938</ref><br />
<ref name="Markham1975"> R. G. Markham and R. G. H. Robertson, NIM '''129''', 131 (1975) https://doi.org/10.1016/0029-554X(75)90122-6 </ref><br />
consists of an ion drift chamber with a set of delay lines to detect the position of a particle along the focal plane and a plastic scintillator to detect the energy of the incoming particle. Using the energy loss of the particle through the ion chamber with the energy deposited in the scintillator, particles of different charges and masses can be identified.<br />
<br />
The typical pressure of the drift chamber is 70 to 300 Torr of isobutane gas [HC(CH3)3]. The pressure controls the density of the gas and affects the bias voltage, it further affects the drift velocity.<br />
<br />
{|class='wikitable'<br />
|+ Table of pressure and bias voltages. Data was taken from the Ph.D. thesis of Erin Good (2020)<br />
! Gas pressure (Torr) !! Anode bias (V) !! Cathode plate bias (V) <br />
|-<br />
| 70 || +1050 to +1035 || -550 to -500<br />
|-<br />
| 80 || +1150 || -550<br />
|-<br />
| 100 || +1250 || -600<br />
|-<br />
| 110 || +1200 to 1320 || -620 to -600<br />
|-<br />
| 125 || +1425 || -650<br />
|-<br />
| 130 || +1360 || -725<br />
|-<br />
| 150 || +1500 || -700<br />
|-<br />
|}<br />
<br />
From bottom to top, the cathode plate, drift region (contains four biased field-shaping wire grids), Frisch grid (grounded), three anode wires, and pickup pads (which are with the delay lines). Electrons induced by any radiation will drift upward, pass the Frisch grid, are accelerated by the anodes, and hit the pickup pads. The pickup pads are strips with 45° against the anode wires, almost parallel to the particle trajectories<ref name="Markham1975" />. Each pickup strip is 0.09" (2.286 mm) wide and 1.4" (35.56 mm) long, and spaced 0.01" (0.245 mm). A total of 440 lead-coated copper strips with a 5 ns delay per strip results in a nominal total delay of 2.2 μs. Every 10 strips share a delay chip. The position of the hit position can then be determined by the time difference at the end of the delay line.<br />
<br />
There are two position-sensitive delay lines (separated by 42.8625 mm) in the focal plane detector. By reconstructing the particle trajectory using the position information of both delay lines, the resolution can be enhanced by correcting for the kinematic shift of the reaction.<br />
<br />
After passing the drift chamber, the particles will be stopped and detected in a plastic scintillator with a photomultiplier tube (PMT) at each end. Together with the energy loss, obtained by the cathode in the drift chamber, a ΔE-E particle identification can be done.<br />
<br />
<br />
== Outline of the algorithm ==<br />
<br />
There are 9 readouts channels from the focal plane detector: <br />
{| class="wikitable"<br />
! readout !! type of signal <br />
|-<br />
| cathode || energy loss<br />
|-<br />
| Front delay line Left || timing<br />
|-<br />
| Front delay line Right || timing<br />
|-<br />
| Front anode || energy loss<br />
|-<br />
| Rear delay line Left || timing<br />
|-<br />
| Rear delay line Right || timing<br />
|-<br />
| Rear anode || energy loss<br />
|-<br />
| PMT Left || energy loss<br />
|-<br />
| PMT Right || energy loss<br />
|}<br />
<br />
The PID is usually using one of the PMT energy and either the cathode or anode energy. <br />
<br />
The coordinate at the Focal Plane is the conventional one, where z-axis is perpendicular to the focal plane detector, y-axis is the vertical, and x-axis is the z-axis cross y-axis. The positions of the front and Rear planes are constructed by the timestamp. Suppose the timestamp is in ns. <br />
<br />
<math> <br />
x_1 = \frac{t_{FL} - t_{FR}}{2} \frac{1}{2.1} ; ~~~ x_2 = \frac{t_{BL} - t_{BR}}{2} \frac{1}{1.98}<br />
</math><br />
<br />
The position at the center of the focal plane is <br />
<br />
<math><br />
x_{avg} = x_1 + x_2 <br />
</math><br />
<br />
However, for different reactions, there is a z-offset, so that the focal plane is shifted<br />
<br />
<math><br />
x_{avg} = \left(\frac{1}{2} - \frac{z_{o}}{D} \right) x_1 + \left(\frac{1}{2} + \frac{z_{o}}{D} \right) x_2 <br />
</math><br />
<br />
where <math> D = 42.8625~[\textrm{mm}] </math> is the distance between the front and rear delay lines.<br />
<br />
=== Calculation of the z-offset ===<br />
<br />
The z-offset depends on the reaction, the angle <math> \theta </math>, and the magnetic field of the spilt-pole. Suppose we know the KE <math> T_b </math> and momentum <math> P </math> of the ejectile or the interested particle that goes into the split-pole, The reaction is denoted as A(a,b)B, where a is the beam (projectile), A is the target, B is the heavy recoil (residual),and b is the recoil (ejectile).<br />
<br />
<math> P^2 = (m_b+T_b)^2 - m_b^2 = T_b(T_b + 2m_b)~[\textrm{MeV/c}^2]</math><br />
<br />
<math> \rho = \frac{P}{c Z B}~[\textrm{m}] </math>, where <math> c = 299.792458 </math>, <math>Z</math> is the charge number, and <math>B</math> is the magnetic field in Tesla.<br />
<br />
<math> k = \frac{v \sin(\theta)}{ m_b + m_B - v \cos(\theta)},~~~ v = \sqrt{\frac{m_a m_B T_a}{T_b}}</math><br />
<br />
<math> z_o = -\rho \delta_x M_x k [\textrm{m}]</math><br />
<br />
where <math> \delta_x = 1.96 </math> is the x-dispersion and <math> M_x = 0.39</math> is the x-magnification.<br />
<br />
=== Simplification of the z-offset calculation (IW) ===<br />
<br />
The Kinematic Factor k can be re-written as a function of the beam and ejectile momenta: <br />
<br />
<math> k = \frac{(p_a/p_b) \sin(\theta)}{ 1 + m_B/m_b - (p_a/p_b) \cos(\theta)} </math><br />
<br />
Inserting that into the offset formula and using <math> p_b = B \rho q_b </math> gives<br />
<br />
<math> z_o = - \delta_x M_x \frac{(p_a/B q_b) \sin(\theta) }{ 1 + m_B/m_b - (p_a/(B \rho q_b)) \cos(\theta)} </math>,<br />
<br />
which only depends on the beam momentum, spectrograph angle and B and the corresponding masses.<br />
<br />
== Kinematic correction of the focal plane == <br />
<br />
As pointed out before, the [[Split-Pole_Spectrograph#Kinematic_broadening | kinematic broadening]] can be corrected. In SPS, the dispersion D is 1.96, magnification is 0.39. <br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:AnnotatedFocalPlaneRay.png | 400px|frameless| ]] <br />
| style="width: 400px;"| [[File:FPShift.gif|frame|]]<br />
|-<br />
|Simulated rays near the focal plane. || An animation on the shift of the focal panel. An optimum is reached at FP = -42 mm.<br />
|}<br />
<br />
[[File:XavgDiagram.png|thumb| construction of Xavg (X-average) on the virtual focal plan (a liner plane in this case). Need to redraw the picture, the Y-axis should be Z-axis, and it should be rotated 180 degree, so the particle is from bottom to top.]]<br />
A parallel shift of the focal plane maybe not be enough. Suppose the best focal plan is given by a function <math> z = f(x) </math>. The 2 positions extracted from the front and rear delay lines are <math> x_1, x_2 </math>, and the distance between the front and rear delay lines is <math> d</math>. The X-avg is the solution of the equation:<br />
<br />
<math> f(x) = \frac{x_2 - x_1}{d} \left( x - \frac{x_2 + x_1}{2} \right) </math><br />
<br />
For a linear tilted plane <math> f(x) = m x + z_0 </math>, the X-avg is <br />
<br />
<math> X_{avg} = \frac{x_1^2 - x_2^2 - 2d z_0 }{2 (d m + x_1 - x_2) } </math><br />
<br />
<br />
<!--[[File:TwoBodyKinematics.png|thumb]]--><br />
<br />
= SABRE =<br />
<br />
[[File:SABER installing particle shield.png|thumb|right|Installing particle shield on SABRE (photo taken on May 5, 2022)]]<br />
<br />
SABRE is a '''S'''ilicon '''A'''rray for '''B'''ranching '''R'''atio '''E'''xperiments <br />
<ref> E. C. Good ''et. al'', NIM A '''1003''', 165299 (2021) https://www.sciencedirect.com/science/article/pii/S0168900221002837</ref> <br />
with the SPS. Its predecessor is the Yale Lamp Shade Array (YLSA). SABRE sits at backward angles from the target and covers roughly 30% of 4π. SABRE has both thick and thin dead-layer detectors, with the thin dead-layer detectors capable of reaching ~200 keV thresholds for protons and deuterons.<br />
<br />
= CeBrA =<br />
<br />
[[File:CeBrA array diagram.png|thumb| Solid Works drawing of the fully planned array, which will consist of 13 CeBr<sub>3</sub> detectors.]]<br />
<br />
The Cerium Bromide Array (CeBrA) <ref> A. L. Conley ''et al.'', NIM A '''1058''' (2023) 168827 https://doi.org/10.1016/j.nima.2023.168827 </ref> is a γ-ray detector array designed to be used in conjunction with the SE-SPS. Comprised of low-background CeBr<sub>3</sub> scintillators with Hamamatsu photomultipliers. There are currently 7 commissioned detectors in the array with varying size crystals (2-1x1 inch, 4-2x2 inch, and 1-3x4 inch crystal detectors; a schematic for the full array on is shown on the right). The goal of CeBrA is to establish coincident events with the light-ions detected in the focal plane detector of the SE-SPS and the corresponding γ-rays from the excited recoiling nucleus, which are called particle-gamma coincidences. The scattering chamber used for CeBrA differs from the usual sliding-seal chamber that is used with the SE-SPS. With a hemisphere shape, it sits at a fixed 35<sup>o</sup> angle relative to the SE-SPS and allows for a more detailed study of the electromagnetic transitions from nuclei excited in reactions using the SE-SPS.<br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:Current_array.jpg | 400px|frameless|]] <br />
|-<br />
|Current array setup for CeBrA as it was used in the Summer 2023 REU experiments studying the <sup>52</sup>Cr(d,pγ)<sup>53</sup>Cr and <sup>34</sup>S(d,pγ)<sup>35</sup>S reactions, which was a follow up from the previous REU from 2022.<br />
|}<br />
<br />
= Repositories =<br />
https://github.com/sesps<br />
<br />
= Contact =<br />
* Jeff Blackmon mailto:blackmon@lsu.edu<br />
* Mark-Christoph Spieker mailto:mspieker@fsu.edu<br />
* Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
* <span style=color:red">who should be contacted? </span><br />
<br />
= References =</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Split-Pole_Spectrograph&diff=2393Split-Pole Spectrograph2024-06-20T19:42:31Z<p>Iwiedenhoever: /* Calculation of the z-offset */</p>
<hr />
<div>[[File:Sideview of the split-pole spectrometer.jpg|none| 800px | Side view of the spilt-pole spectrometer]]<br />
<br />
{| align="right" style="width:30%;"<br />
|-<br />
| [[File:SPS Pictue Annotated.png|thumb|Annotated picture of the SE-SPS, An plain picture is here : [[:File:SPS Magnet.png]]]] || [[File:SPS Picture ray.png|thumb| SE-SPS COSY simulation. An plain picture is here [[:File:SPS Sketch With Cosy.png]]]]<br />
|}<br />
<br />
The '''Super Enge Split-Pole Spectrograph''' <br />
<ref name="Enge1979">H.A. Enge, NIM '''162''', 161 (1979) https://doi.org/10.1016/0029-554X(79)90711-0</ref><br />
<ref>H. A. Enge, NIM '''187''', 1 (1981) https://doi.org/10.1016/0029-554X(81)90465-1 </ref><br />
is a magnet spectrometer to measure the spectrum of nuclear reactions. The concept and design were developed by [https://en.wikipedia.org/wiki/Harald_A._Enge Harald A. Enge]<ref>J. E. Spencer and H. A. Enge, NIM '''49''', 181 (1967) https://doi.org/10.1016/0029-554X(67)90684-2 </ref> at 1967, aimed to have a broad-momentum range spectrograph with <math> p_{max}/p_{min} \approx 2.8 </math> or <math> E_{max}/E_{min} \approx 8 </math>. The spectrometer was originally located at the Wright Nuclear Structure Laboratory (closed at 2013), at Yale University. It was moved to FSU in the fall of 2013. It consists of a reaction chamber, a '''split-pole magnetic spectrograph''', a '''position-sensitive ionization drift chamber''', and a '''plastic scintillator'''. It has an angular acceptance of 128 msr (vertical ±40 mrad, horizontal ±80 mrad). The maximum B-field is 1.63 T with a radius of curvature from 511 mm to 920 mm. The mean radius is 600 mm. The advantage of the split-pole instead of a single-pole magnet is the aberration (x|θ<sup>2</sup>) and (x|φ<sup>2</sup>) are almost zero <ref name="Enge1979" />. <br />
<br />
The '''Super''' Enge Split-Pole Spectrograph is an upgrade of the Yale Enge SPS. The major change is the redesign of the backward silicon detector array to the [[Split-Pole_Spectrograph#SABRE|SABRE]].<br />
<br />
= SPS Experiment Guide =<br />
[[Media:SPS_Experiment_Guide.pdf]]<br />
<br />
= SPS Operating Procedures =<br />
I created this section as a place to store procedures for the chamber swaps, however, I expect there are other things we might want to document here. -p<br />
* [[Target Chamber Swaps]]<br />
<br />
= Online Simulator = <br />
<br />
https://fsunuc.physics.fsu.edu/SPS/<br />
<br />
There was another simulator called [https://github.com/gwm17/websps websps] developed by Gordon. But I am unable to revive it after the server upgraded from Ubuntu 20.04 to Ubuntu 22.04, so I write a new one using javascript. The missing part is the energy loss calculation.<br />
<br />
= Magnet =<br />
[[File:Design of a Split-pole spectrograph.png|thumb|Design of a Split-pole spectrograph. Take from Ref. <ref name="Enge1979"/>]]<br />
<br />
The primary goal of a spectrograph is resolving momentum. A general discussion of magnetic spectrographs can be found at Ref. <ref name="Enge1979" /> and Ref. <ref> H. A. Enge, Physics Today '''20''', 65 (1967) https://doi.org/10.1063/1.3034401 </ref>. There are many designs from a simple single dipole to a combination of multiple dipoles and quadrupoles. <br />
<br />
The SPS magnet was designed for a large solid angle, large resolving power, and correction of kinematic broadening. Using two-directional focusing and second-order focusing spectrograph can achieve a large sold angle and resolving power. Second-order focusing means the second-order terms in the acceptance angles vanish, i.e. no aberration.<br />
<br />
The SPS contains 2 separate poles enveloped by a single coil. The split provides second-order double focusing over a broad range of momenta. The magnet can be rotated from 0 to 55 degrees in the lab. The magnetic field has an upper limit of 1.63 T (or 16.3 kG).<br />
<br />
{| class="wikitable"<br />
|+ This table is taken from B.P. Kay Ph.D thesis (2007)<br />
! Property !! Symbol !! Value<br />
|-<br />
| Orbital radius || <math> \rho </math> || 511 to 920 mm<br />
|-<br />
|Resolving power || <math> p/\Delta p </math> || 1st order of <math> (x|\theta) </math>4290 (at <math>\theta = \pm 80 </math> mrad) <br />
|- <br />
|rowspan="2"| Acceptance || Horizontal || 160 mrad<br />
|-<br />
| Vertical || 80 mrad<br />
|-<br />
| Dispersion || <math> D=(x|\delta) </math> || 1.96<br />
|-<br />
|rowspan="2" | Magnification || <math> M_x = (x|x)</math> || 0.39<br />
|-<br />
| <math> M_y = (y|y)</math> || 2.9<br />
|-<br />
| Maximum field || <math> B </math> || 1.63 T<br />
|}<br />
<br />
== Transfer matrix and COSY INFINITY simulation ==<br />
[[File:Schematics of ion-beam optical element.png|thumb|An illustration of the coordinate of an optical element. This is taken from H.A. Enge NIM 162, 161 (1979).]]<br />
{{Notice | need to fill up. Any 1st few orders transfer matrixes?}}<br />
<br />
The entrance coordinates of the beam are <math> x_1, y_1, \theta_1, \phi_1 </math> wiht momentum <math> \delta = p/p_0 </math>, and coordinate at exit are <math> x_2, y_2, \theta_2, \phi_2 </math>. The entrance and exit coordinates are related by <br />
<br />
<math> x_2 = f_x(x_1, y_1, \theta_1, \phi_1, \delta) </math><br />
<br />
using Taylor expansion:<br />
<br />
<math> \frac{x_2}{\rho} = (x|x) \frac{x_1}{\rho} + (x|\theta) \theta_1 + (x|\delta) \delta + (x|\theta^2) \theta_1^2 + ... </math><br />
<br />
In the above expansion, the term <math> (x|x) </math> is the '''magnification''' in the x-direction. <math> (x|\delta) </math> is the '''dispersion''', and <math> (x|\theta^2) </math> is '''aberration'''. The '''focal plane''' is the z-position that <math> (x|\theta) = 0 </math>, i.e. the exit <math> x_2 </math> does not depend on the entrance angle. <br />
<br />
=== Kinematic broadening ===<br />
[[File:Kinematic correction of spectrometer.png|thumb|Kinematic correction of spectrometer. Taken from H. A. Enge NIM 162, 161 (1979)]]<br />
<br />
Kinematic broadening is the broadening of focus for the same reaction state. After a reaction, the angle and momentum of the recoil particle are related that the entrance angle <math> \theta_1 = f(\delta)</math> is a function of momentum. For each energy state, the relation between the angle and momentum is unique. For example, in a 2-body transfer reaction, the momentum vector is <br />
<br />
<math> ( p_x, p_z ) = ( k \sin(\theta), \gamma \beta \sqrt{m^2-k^2} + \gamma k \cos(\theta) ) </math><br />
<br />
where <math> k, \theta</math> are the momentum and the scattering angle at the CM frame, <math> \gamma, \beta </math> are the Lorentz factor from Lab frame to CM frame, and <math> m </math> is the mass of the particle. All 5 coefficients are constant for a fixed energy state. And the different state is characterized by <math> k </math>. Defined the kinematic factor K:<br />
<br />
<math> K = \frac{1}{p} \frac{dp}{d\theta_1} = \frac{\beta E \sin(\theta)}{ k + \beta \sqrt{m^2 - k^2} \cos(\theta)} </math><br />
<br />
The kinematic broadening can be corrected by shifting the focal plane by <br />
<br />
<math> \Delta z = - D M \rho K, D = (x|\delta), M = (x|x) </math><br />
<br />
= Focal plane detector =<br />
[[File:Focal plane detector.png|400px|thumb|right|Front view of the opened camerabox. The SPS focal plane detector with the front window removed is at the bottom.]]<br />
<br />
[[File:Side Cross section view of the SPS focal plane detector.png|400px|thumb|Side Cross section view of the SPS focal plane detector. Taken from B.P. Kay Ph.D. thesis (2007).]]<br />
<br />
[[File:PID EDE annoteted.png|400px|thumb]]<br />
<br />
{{Notice | The drift ion chamber was repaired in summer 2018 }}<br />
<br />
The focal plane detector <br />
<ref> C. Marshal ''et. al'', IEEE Tran. Inst. and Meas. '''68''', 533 (2018) https://doi.org/10.1109/TIM.2018.2847938</ref><br />
<ref name="Markham1975"> R. G. Markham and R. G. H. Robertson, NIM '''129''', 131 (1975) https://doi.org/10.1016/0029-554X(75)90122-6 </ref><br />
consists of an ion drift chamber with a set of delay lines to detect the position of a particle along the focal plane and a plastic scintillator to detect the energy of the incoming particle. Using the energy loss of the particle through the ion chamber with the energy deposited in the scintillator, particles of different charges and masses can be identified.<br />
<br />
The typical pressure of the drift chamber is 70 to 300 Torr of isobutane gas [HC(CH3)3]. The pressure controls the density of the gas and affects the bias voltage, it further affects the drift velocity.<br />
<br />
{|class='wikitable'<br />
|+ Table of pressure and bias voltages. Data was taken from the Ph.D. thesis of Erin Good (2020)<br />
! Gas pressure (Torr) !! Anode bias (V) !! Cathode plate bias (V) <br />
|-<br />
| 70 || +1050 to +1035 || -550 to -500<br />
|-<br />
| 80 || +1150 || -550<br />
|-<br />
| 100 || +1250 || -600<br />
|-<br />
| 110 || +1200 to 1320 || -620 to -600<br />
|-<br />
| 125 || +1425 || -650<br />
|-<br />
| 130 || +1360 || -725<br />
|-<br />
| 150 || +1500 || -700<br />
|-<br />
|}<br />
<br />
From bottom to top, the cathode plate, drift region (contains four biased field-shaping wire grids), Frisch grid (grounded), three anode wires, and pickup pads (which are with the delay lines). Electrons induced by any radiation will drift upward, pass the Frisch grid, are accelerated by the anodes, and hit the pickup pads. The pickup pads are strips with 45° against the anode wires, almost parallel to the particle trajectories<ref name="Markham1975" />. Each pickup strip is 0.09" (2.286 mm) wide and 1.4" (35.56 mm) long, and spaced 0.01" (0.245 mm). A total of 440 lead-coated copper strips with a 5 ns delay per strip results in a nominal total delay of 2.2 μs. Every 10 strips share a delay chip. The position of the hit position can then be determined by the time difference at the end of the delay line.<br />
<br />
There are two position-sensitive delay lines (separated by 42.8625 mm) in the focal plane detector. By reconstructing the particle trajectory using the position information of both delay lines, the resolution can be enhanced by correcting for the kinematic shift of the reaction.<br />
<br />
After passing the drift chamber, the particles will be stopped and detected in a plastic scintillator with a photomultiplier tube (PMT) at each end. Together with the energy loss, obtained by the cathode in the drift chamber, a ΔE-E particle identification can be done.<br />
<br />
<br />
== Outline of the algorithm ==<br />
<br />
There are 9 readouts channels from the focal plane detector: <br />
{| class="wikitable"<br />
! readout !! type of signal <br />
|-<br />
| cathode || energy loss<br />
|-<br />
| Front delay line Left || timing<br />
|-<br />
| Front delay line Right || timing<br />
|-<br />
| Front anode || energy loss<br />
|-<br />
| Rear delay line Left || timing<br />
|-<br />
| Rear delay line Right || timing<br />
|-<br />
| Rear anode || energy loss<br />
|-<br />
| PMT Left || energy loss<br />
|-<br />
| PMT Right || energy loss<br />
|}<br />
<br />
The PID is usually using one of the PMT energy and either the cathode or anode energy. <br />
<br />
The coordinate at the Focal Plane is the conventional one, where z-axis is perpendicular to the focal plane detector, y-axis is the vertical, and x-axis is the z-axis cross y-axis. The positions of the front and Rear planes are constructed by the timestamp. Suppose the timestamp is in ns. <br />
<br />
<math> <br />
x_1 = \frac{t_{FL} - t_{FR}}{2} \frac{1}{2.1} ; ~~~ x_2 = \frac{t_{BL} - t_{BR}}{2} \frac{1}{1.98}<br />
</math><br />
<br />
The position at the center of the focal plane is <br />
<br />
<math><br />
x_{avg} = x_1 + x_2 <br />
</math><br />
<br />
However, for different reactions, there is a z-offset, so that the focal plane is shifted<br />
<br />
<math><br />
x_{avg} = \left(\frac{1}{2} - \frac{z_{o}}{D} \right) x_1 + \left(\frac{1}{2} + \frac{z_{o}}{D} \right) x_2 <br />
</math><br />
<br />
where <math> D = 42.8625~[\textrm{mm}] </math> is the distance between the front and rear delay lines.<br />
<br />
=== Calculation of the z-offset ===<br />
<br />
The z-offset depends on the reaction, the angle <math> \theta </math>, and the magnetic field of the spilt-pole. Suppose we know the KE <math> T_b </math> and momentum <math> P </math> of the ejectile or the interested particle that goes into the split-pole, The reaction is denoted as A(a,b)B, where a is the beam (projectile), A is the target, B is the heavy recoil (residual),and b is the recoil (ejectile).<br />
<br />
<math> P^2 = (m_b+T_b)^2 - m_b^2 = T_b(T_b + 2m_b)~[\textrm{MeV/c}^2]</math><br />
<br />
<math> \rho = \frac{P}{c Z B}~[\textrm{m}] </math>, where <math> c = 299.792458 </math>, <math>Z</math> is the charge number, and <math>B</math> is the magnetic field in Tesla.<br />
<br />
<math> k = \frac{v \sin(\theta)}{ m_b + m_B - v \cos(\theta)},~~~ v = \sqrt{\frac{m_a m_B T_a}{T_b}}</math><br />
<br />
<math> z_o = -\rho \delta_x M_x k [\textrm{m}]</math><br />
<br />
where <math> \delta_x = 1.96 </math> is the x-dispersion and <math> M_x = 0.39</math> is the x-magnification.<br />
<br />
=== Simplification of the z-offset calculation (IW) ===<br />
<br />
The Kinematic Factor k can be re-written as a function of the beam and ejectile momenta: <br />
<br />
<math> k = \frac{(p_a/p_b) \sin(\theta)}{ 1 + m_B/m_b - (p_a/p_b) \cos(\theta)} </math><br />
<br />
Inserting that into the offset formula and using <math> p_b = B \rho q_b </math> gives<br />
<br />
<math> z_o = - \delta_x M_x \frac{(p_a/B q_b) \sin(\theta) }{ 1 + m_B/m_b - (p_a/(B \rho q_b)) \cos(\theta)} </math>,<br />
<br />
== Kinematic correction of the focal plane == <br />
<br />
As pointed out before, the [[Split-Pole_Spectrograph#Kinematic_broadening | kinematic broadening]] can be corrected. In SPS, the dispersion D is 1.96, magnification is 0.39. <br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:AnnotatedFocalPlaneRay.png | 400px|frameless| ]] <br />
| style="width: 400px;"| [[File:FPShift.gif|frame|]]<br />
|-<br />
|Simulated rays near the focal plane. || An animation on the shift of the focal panel. An optimum is reached at FP = -42 mm.<br />
|}<br />
<br />
[[File:XavgDiagram.png|thumb| construction of Xavg (X-average) on the virtual focal plan (a liner plane in this case). Need to redraw the picture, the Y-axis should be Z-axis, and it should be rotated 180 degree, so the particle is from bottom to top.]]<br />
A parallel shift of the focal plane maybe not be enough. Suppose the best focal plan is given by a function <math> z = f(x) </math>. The 2 positions extracted from the front and rear delay lines are <math> x_1, x_2 </math>, and the distance between the front and rear delay lines is <math> d</math>. The X-avg is the solution of the equation:<br />
<br />
<math> f(x) = \frac{x_2 - x_1}{d} \left( x - \frac{x_2 + x_1}{2} \right) </math><br />
<br />
For a linear tilted plane <math> f(x) = m x + z_0 </math>, the X-avg is <br />
<br />
<math> X_{avg} = \frac{x_1^2 - x_2^2 - 2d z_0 }{2 (d m + x_1 - x_2) } </math><br />
<br />
<br />
<!--[[File:TwoBodyKinematics.png|thumb]]--><br />
<br />
= SABRE =<br />
<br />
[[File:SABER installing particle shield.png|thumb|right|Installing particle shield on SABRE (photo taken on May 5, 2022)]]<br />
<br />
SABRE is a '''S'''ilicon '''A'''rray for '''B'''ranching '''R'''atio '''E'''xperiments <br />
<ref> E. C. Good ''et. al'', NIM A '''1003''', 165299 (2021) https://www.sciencedirect.com/science/article/pii/S0168900221002837</ref> <br />
with the SPS. Its predecessor is the Yale Lamp Shade Array (YLSA). SABRE sits at backward angles from the target and covers roughly 30% of 4π. SABRE has both thick and thin dead-layer detectors, with the thin dead-layer detectors capable of reaching ~200 keV thresholds for protons and deuterons.<br />
<br />
= CeBrA =<br />
<br />
[[File:CeBrA array diagram.png|thumb| Solid Works drawing of the fully planned array, which will consist of 13 CeBr<sub>3</sub> detectors.]]<br />
<br />
The Cerium Bromide Array (CeBrA) <ref> A. L. Conley ''et al.'', NIM A '''1058''' (2023) 168827 https://doi.org/10.1016/j.nima.2023.168827 </ref> is a γ-ray detector array designed to be used in conjunction with the SE-SPS. Comprised of low-background CeBr<sub>3</sub> scintillators with Hamamatsu photomultipliers. There are currently 7 commissioned detectors in the array with varying size crystals (2-1x1 inch, 4-2x2 inch, and 1-3x4 inch crystal detectors; a schematic for the full array on is shown on the right). The goal of CeBrA is to establish coincident events with the light-ions detected in the focal plane detector of the SE-SPS and the corresponding γ-rays from the excited recoiling nucleus, which are called particle-gamma coincidences. The scattering chamber used for CeBrA differs from the usual sliding-seal chamber that is used with the SE-SPS. With a hemisphere shape, it sits at a fixed 35<sup>o</sup> angle relative to the SE-SPS and allows for a more detailed study of the electromagnetic transitions from nuclei excited in reactions using the SE-SPS.<br />
<br />
{|class='wikitable'<br />
| style="width: 400px;"| [[File:Current_array.jpg | 400px|frameless|]] <br />
|-<br />
|Current array setup for CeBrA as it was used in the Summer 2023 REU experiments studying the <sup>52</sup>Cr(d,pγ)<sup>53</sup>Cr and <sup>34</sup>S(d,pγ)<sup>35</sup>S reactions, which was a follow up from the previous REU from 2022.<br />
|}<br />
<br />
= Repositories =<br />
https://github.com/sesps<br />
<br />
= Contact =<br />
* Jeff Blackmon mailto:blackmon@lsu.edu<br />
* Mark-Christoph Spieker mailto:mspieker@fsu.edu<br />
* Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
* <span style=color:red">who should be contacted? </span><br />
<br />
= References =</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=FSU_Fox%27s_Lab_Wiki&diff=2373FSU Fox's Lab Wiki2024-05-28T15:25:28Z<p>Iwiedenhoever: /* Accelerator Operation Procedures */</p>
<hr />
<div><br />
= Introduction =<br />
<br />
*This is the wiki for all details about FSU [[John D Fox]]' Lab for nuclear physics.<br />
*The original manual can be found in [[:File:FoxManual20200415.pdf]].<br />
*This wiki is <b><span style="color:red">OPEN TO PUBLIC</span></b>. Any confidential material should be put in <b>[http://elog.physics.fsu.edu elog]</b> or use internal pages.<br />
*For [https://www.lsu.edu/physics/research/nuclear-physics.php Louisiana State University] users, please see [https://fsunuc.physics.fsu.edu/elog/202204_SPS_Blocker/2 this elog] for acessing the [[Fox's Lab Network]].<br />
*New account may like to see the wiki syntax in [[Wiki_Edit_Cheat_Sheet | here]].<br />
<br />
= Accelerator Operation Procedures =<br />
● [[Radiation Safety]]<br />
<br />
= Hardware = <br />
{|style="width: 100%;"<br />
|● [[Tandem Accelerator]] || ● [[LINAC]]<br />
|-<br />
|● [[SF6 Gas Handling System]] || ● [[Vacuum Systems]]<br />
|-<br />
|● [[Water Cooling System]] || ● [[He refrigerator]]<br />
|-<br />
|● [[Computers Network]] || ● [[Hardware/Cable Changes for Switching Target Rooms]]<br />
|-<br />
|● [[Ion Sources]]: This includes the [[Ion Sources#Sputter Source|Sputter Source]] and [[Ion Sources#RF Source|RF Source]] || ● [[Target Lab]]<br />
|-<br />
|● [[RESOLUT]]: In-flight radioactive beam facility<br />
|-<br />
|● [[Triton Beam Project]]: Multi-SNICS with Tritium Cathodes<br />
|}<br />
<br />
== Detector stations ==<br />
<br />
{|style="width: 100%;"<br />
|● [[ANASEN]] || ● [[CATRiNA]]<br />
|-<br />
|● [[Clarion2]] || ● [[ENCORE]]<br />
|-<br />
|● [[Gamma Station]] || ● [[RESONEUT]]<br />
|-<br />
|● [[Split-Pole Spectrograph]]<br />
|-<br />
|● [[Penning Trap]]<br />
|}<br />
<br />
== DAQ systems==<br />
{|style="width: 100%;"<br />
|● [[Pixie16 digitizer]] || ● [[CAEN digitizer]]<br />
|-<br />
|● [[Mesytec]] || ● [[NSCL DAQ]] / [[NSCL SpecTcl]]<br />
|}<br />
<br />
= Software & Resources = <br />
<br />
{|style="width: 100%;"<br />
|◆[[Online Resources]]: Web server, Elog, Grafana, Wiki, InfluxDB || ◆[[Data Server]]<br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/git/explore/repos Git repository] by Gitea || ◆[[Github repositories]] <br />
|-<br />
|◆[[SSH tunneling]] || ◆[[VNC viewer]]<br />
|-<br />
|◆[[Slack Channel]] || ◆[[gnuscope]]<br />
|-<br />
|◆[[SolidWorks]] || ◆[[Online Analysis]]<br />
|-<br />
| ◆[[Raspberry Pi Camera]] || ◆[[Python Iseg HV controller]] <br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/research/publication_list/ List of Publications]<br />
|}<br />
<br />
= Layout of the Laboratory =<br />
{|<br />
|[[File:Lab Model.png|450px|frameless|none]] || [[File:JohnDFoxLayout.png|550px|frameless|none]] <br />
|}<br />
<!--[[File:NRBbasement.png|1000px|thumb|none]]--><br />
<br />
= External Collaborations = <br />
<br />
* [[LSU Collaboration]]<br />
* [[ORNL Collaboration]]<br />
* [[TRIUMF Collaboration]]<br />
* [[FRIB FDSi e21062]]<br />
* [[FRIB SOLARIS Collaboration]]<br />
* [[ANL MUSIC Collaboration]]<br />
<br />
= Past Experiments =<br />
<br />
[[List of Past Experiments]]<br />
<br />
= Other Resources =<br />
<br />
* [[Journal Club]]<br />
<br />
* [[Help Call List for Evenings, Weekends, Holidays]]<br />
<br />
* [[Laboratory Infrastructure]]<br />
<br />
* [[Wiki Edit Cheat Sheet]]<br />
<br />
* [[Guide for using this wiki]]<br />
<br />
* [https://www.qr-code-generator.com/ QR code generator]<br />
<br />
* [[Weekly Tandem Maintenance]]<br />
<br />
* [[Source Sign Out Sheet]]<br />
<br />
= Contacts = <br />
<br />
{|<br />
| for accelerator ||: Lagy Baby mailto:lbaby@fsu.edu <br>: Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
|-<br />
| for vacuum ||: Powell Barber mailto:pbarber@fsu.edu<br />
|-<br />
| for ion sources || : Brian Schmidt mailto:bschmidt@fsu.edu<br />
|-<br />
| for LINAC || : David Spinger mailto: dspingler@fsu.edu<br />
|-<br />
| for IT and DAQ ||: Ryan Tang mailto:rtang@fsu.edu<br />
|-<br />
|}</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=FSU_Fox%27s_Lab_Wiki&diff=2372FSU Fox's Lab Wiki2024-05-28T15:22:46Z<p>Iwiedenhoever: /* Accelerator Operation Procedures */</p>
<hr />
<div><br />
= Introduction =<br />
<br />
*This is the wiki for all details about FSU [[John D Fox]]' Lab for nuclear physics.<br />
*The original manual can be found in [[:File:FoxManual20200415.pdf]].<br />
*This wiki is <b><span style="color:red">OPEN TO PUBLIC</span></b>. Any confidential material should be put in <b>[http://elog.physics.fsu.edu elog]</b> or use internal pages.<br />
*For [https://www.lsu.edu/physics/research/nuclear-physics.php Louisiana State University] users, please see [https://fsunuc.physics.fsu.edu/elog/202204_SPS_Blocker/2 this elog] for acessing the [[Fox's Lab Network]].<br />
*New account may like to see the wiki syntax in [[Wiki_Edit_Cheat_Sheet | here]].<br />
<br />
= Accelerator Operation Procedures =<br />
● [[Radiation Safety]]<br />
● [[Tritium Operation Procedures]]<br />
<br />
= Hardware = <br />
{|style="width: 100%;"<br />
|● [[Tandem Accelerator]] || ● [[LINAC]]<br />
|-<br />
|● [[SF6 Gas Handling System]] || ● [[Vacuum Systems]]<br />
|-<br />
|● [[Water Cooling System]] || ● [[He refrigerator]]<br />
|-<br />
|● [[Computers Network]] || ● [[Hardware/Cable Changes for Switching Target Rooms]]<br />
|-<br />
|● [[Ion Sources]]: This includes the [[Ion Sources#Sputter Source|Sputter Source]] and [[Ion Sources#RF Source|RF Source]] || ● [[Target Lab]]<br />
|-<br />
|● [[RESOLUT]]: In-flight radioactive beam facility<br />
|-<br />
|● [[Triton Beam Project]]: Multi-SNICS with Tritium Cathodes<br />
|}<br />
<br />
== Detector stations ==<br />
<br />
{|style="width: 100%;"<br />
|● [[ANASEN]] || ● [[CATRiNA]]<br />
|-<br />
|● [[Clarion2]] || ● [[ENCORE]]<br />
|-<br />
|● [[Gamma Station]] || ● [[RESONEUT]]<br />
|-<br />
|● [[Split-Pole Spectrograph]]<br />
|-<br />
|● [[Penning Trap]]<br />
|}<br />
<br />
== DAQ systems==<br />
{|style="width: 100%;"<br />
|● [[Pixie16 digitizer]] || ● [[CAEN digitizer]]<br />
|-<br />
|● [[Mesytec]] || ● [[NSCL DAQ]] / [[NSCL SpecTcl]]<br />
|}<br />
<br />
= Software & Resources = <br />
<br />
{|style="width: 100%;"<br />
|◆[[Online Resources]]: Web server, Elog, Grafana, Wiki, InfluxDB || ◆[[Data Server]]<br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/git/explore/repos Git repository] by Gitea || ◆[[Github repositories]] <br />
|-<br />
|◆[[SSH tunneling]] || ◆[[VNC viewer]]<br />
|-<br />
|◆[[Slack Channel]] || ◆[[gnuscope]]<br />
|-<br />
|◆[[SolidWorks]] || ◆[[Online Analysis]]<br />
|-<br />
| ◆[[Raspberry Pi Camera]] || ◆[[Python Iseg HV controller]] <br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/research/publication_list/ List of Publications]<br />
|}<br />
<br />
= Layout of the Laboratory =<br />
{|<br />
|[[File:Lab Model.png|450px|frameless|none]] || [[File:JohnDFoxLayout.png|550px|frameless|none]] <br />
|}<br />
<!--[[File:NRBbasement.png|1000px|thumb|none]]--><br />
<br />
= External Collaborations = <br />
<br />
* [[LSU Collaboration]]<br />
* [[ORNL Collaboration]]<br />
* [[TRIUMF Collaboration]]<br />
* [[FRIB FDSi e21062]]<br />
* [[FRIB SOLARIS Collaboration]]<br />
* [[ANL MUSIC Collaboration]]<br />
<br />
= Past Experiments =<br />
<br />
[[List of Past Experiments]]<br />
<br />
= Other Resources =<br />
<br />
* [[Journal Club]]<br />
<br />
* [[Help Call List for Evenings, Weekends, Holidays]]<br />
<br />
* [[Laboratory Infrastructure]]<br />
<br />
* [[Wiki Edit Cheat Sheet]]<br />
<br />
* [[Guide for using this wiki]]<br />
<br />
* [https://www.qr-code-generator.com/ QR code generator]<br />
<br />
* [[Weekly Tandem Maintenance]]<br />
<br />
* [[Source Sign Out Sheet]]<br />
<br />
= Contacts = <br />
<br />
{|<br />
| for accelerator ||: Lagy Baby mailto:lbaby@fsu.edu <br>: Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
|-<br />
| for vacuum ||: Powell Barber mailto:pbarber@fsu.edu<br />
|-<br />
| for ion sources || : Brian Schmidt mailto:bschmidt@fsu.edu<br />
|-<br />
| for LINAC || : David Spinger mailto: dspingler@fsu.edu<br />
|-<br />
| for IT and DAQ ||: Ryan Tang mailto:rtang@fsu.edu<br />
|-<br />
|}</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2047Weekly Tandem Maintenance2023-10-05T13:07:27Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel while door is open.<br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2046Weekly Tandem Maintenance2023-10-05T13:07:08Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel while door is open.<br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:\\ \\ \\ \\ \\ \\</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2045Weekly Tandem Maintenance2023-10-05T13:04:44Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel while door is open.<br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:<br />
\\<br />
\\</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2044Weekly Tandem Maintenance2023-10-05T13:04:21Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel while door is open.<br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|<br />
|</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2043Weekly Tandem Maintenance2023-10-05T11:42:58Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel while door is open.<br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2042Weekly Tandem Maintenance2023-10-05T11:41:54Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding status lights on the Control Room interlock panel. <br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel. <br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2041Weekly Tandem Maintenance2023-10-05T11:40:23Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding lights in Control Room<br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel. <br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
<br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2040Weekly Tandem Maintenance2023-10-05T11:39:35Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
{<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding lights in Control Room<br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel. <br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2039Weekly Tandem Maintenance2023-10-05T11:31:07Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding lights in Control Room<br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel. <br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
HE Penning gauge: ________ TORR <br />
LE Penning gauge: ________ TORR <br />
SNICS Penning gauge: _____ TORR<br />
Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
SNICS Backing Line Thermocouple __________________ μ<br />
SNICS Diffusion Pump Thermocouple ________________ μ<br />
SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
LE Cryopump: Head Temperature _____ K <br />
LE Vacuum: Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:Head Temperature _______ K<br />
<br />
HE Vacuum: Penning Gauge 1 ______ TORR, Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump: Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2038Weekly Tandem Maintenance2023-10-05T11:29:11Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
# If no experiment running: Close the Tandem Source - Tandem Vault - TR1 and TR2 doors, then verify the corresponding lights in Control Room<br />
# Activate the audible alarm in the control room and break the interlock by opening the TR1 door. Verify that alarm is audible. <br />
# Verify that the LE Cup can not be retracted at the cup control panel. <br />
# If Tandem is running: Verify the operation of lit signs at the TR1 and TR2 entries, near the film badge rack and the lit sign outside the loading dock. <br />
<br />
'''IN CONTROL ROOM'''<br />
* HE Penning gauge: ________ TORR <br />
* LE Penning gauge: ________ TORR <br />
* SNICS Penning gauge: _____ TORR<br />
* Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
* SNICS Backing Line Thermocouple __________________ μ<br />
* SNICS Diffusion Pump Thermocouple ________________ μ<br />
* SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
<br />
LE Cryopump:<br />
* Head Temperature _____ K <br />
LE Vacuum: <br />
* Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:<br />
* Head Temperature _______ K<br />
<br />
HE Vacuum: <br />
* Penning Gauge 1 ______ TORR<br />
* Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump<br />
* Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
<br />
<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2037Weekly Tandem Maintenance2023-10-05T11:15:18Z<p>Iwiedenhoever: </p>
<hr />
<div>Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
<br />
<br />
'''IN CONTROL ROOM'''<br />
* HE Penning gauge: ________ TORR <br />
* LE Penning gauge: ________ TORR <br />
* SNICS Penning gauge: _____ TORR<br />
* Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
* SNICS Backing Line Thermocouple __________________ μ<br />
* SNICS Diffusion Pump Thermocouple ________________ μ<br />
* SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
<br />
LE Cryopump:<br />
* Head Temperature _____ K <br />
LE Vacuum: <br />
* Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:<br />
* Head Temperature _______ K<br />
<br />
HE Vacuum: <br />
* Penning Gauge 1 ______ TORR<br />
* Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump<br />
* Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
<br />
<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Weekly_Tandem_Maintenance&diff=2036Weekly Tandem Maintenance2023-10-05T11:14:18Z<p>Iwiedenhoever: </p>
<hr />
<div>''Weekly Tandem Maintenance''<br />
<br />
Name: <br />
<br />
Date:<br />
<br />
----<br />
Preliminary:<br />
Use your best judgment to determine if a particular step is not appropriate for today's maintenance!<br />
<br />
# Determine whether or not the tandem or ion sources are currently operating.<br />
# Begin filling the 500 L liquid nitrogen dewar at the linac hall fill station. <br />
# Cheek the previous week's maintenance sheet for uncorrected problems.<br />
----<br />
Checklist: Circle and explain all items on this list, which could not be checked. <br />
<br />
# On the back side of this sheet, record the control room Penning gauge vacuum readings.<br />
# Record the control room tank pressure ____ and temperature ___<br />
# Record propane tank levels. (Located outside by helium tanks.) #1____ #2____<br />
# Check the generator oil and water levels: start the generator and allow it to run until list is complete.<br />
# Check that the Air Compressor Room Exhaust Fan is running ( south wall exterior, room west of emergency generator ) If not, notify staff immediately.<br />
# Record the drop across the lab water filter located south of the LE tandem vault entrance. <br />
# Check the SNICS source deionized cooling water level.<br />
# Check the SNICS source backing pump oil level and two drive belts.<br />
# Check the pressure in the SNICS source argon cylinder; replace if less than 100 psi _____<br />
# Record the SNICS source vacuum gauge readings on the back of this sheet.<br />
# Drain the water from the airline trap (NOT THE OILER) on west side of SNICS source.<br />
# Record the LE cryopump temperature.<br />
# Record the beam line LE Vacuum (Penning gauge) on the back of this sheet. <br />
# Actuate the LE cryopump gate valve.<br />
# There is an unpumped section of beam line between the LE valve and the SNICS source exit valve. If either valve is open, cycle the LE beam line gate valve.<br />
# If the tandem is not running, actuate (close and immediately open) both gas security ball valves. <br />
# Drain the line water trap (NOT THE OILER).<br />
# Ensure that the LE faraday cup rotates and the indicator lights flash.<br />
# Record the Pelletron chain run time hours: #1_____ #2_____<br />
# Record the Scott Airpack pressure _____ (At HE end of the tandem in yellow case.)<br />
# Record the tandem pressure and temperature shown on gauges at HE end of tandem.<br />
# Record the HE cryopump temperature. <br />
# Record the HE pumping station vacuums on the back of this sheet.<br />
# Actuate the HE pumping station gate valve.<br />
# Actuate the HE beamline gate valve.<br />
# Ensure that the HE faraday cup rotates and the indicator lights flash.<br />
# Drain the HE air line water trap (NOT THE OILER).<br />
# Drain the compressor oil from the tandem 90 degree magnet image slits trap.<br />
# Ensure that the faraday cup 2 rotates and the indicator lights flash.<br />
# Record the target room 1-90 degree magnet vacuum on the back of this sheet.<br />
# Record the linac beam line vacuum and actuate entrance gate valve if vacuum permits.<br />
# Record the target room 1-90 degree magnet cryopump temperature back of this sheet.<br />
# Record the target room 1-90 degree magnet pumping station vacuums on the back of this sheet.<br />
# Actuate the target mom 1-90 degree magnet pumping station gate valve.<br />
# Record the switching magnet pumping station vacuums on the back of this sheet.<br />
# Ignore this step until new pump installed: Actuate the switching magnet pumping station gate valve.<br />
# Ensure that all necessary switches are active on the tandem beam line valve status panel and that each item is in the protect mode at the individual device's control box or panel.<br />
# Drain the switching magnet water trap (NOT THE OILER).<br />
# Ensure that the 4 radiation warning signs are lit. Lamps are only lit if tandem or preaccelerator is on.<br />
# Record the emergency generator temperature ___ oil pressure ___ and output voltages.<br />
## 1 _____ 2 _____ 3_____<br />
# Turn off the generator and set switch to REMOTE position.<br />
# Record any problems found and corrected during this maintenance on the back of this sheet. <br />
# Drain the water traps located in the gas handling mom on the north and south walls.<br />
<br />
<br />
'''IN CONTROL ROOM'''<br />
* HE Penning gauge: ________ TORR <br />
* LE Penning gauge: ________ TORR <br />
* SNICS Penning gauge: _____ TORR<br />
* Polarized Ion Source: ____ TORR<br />
<br />
'''IN TANDEM VAULT SOURCE AREA'''<br />
* SNICS Backing Line Thermocouple __________________ μ<br />
* SNICS Diffusion Pump Thermocouple ________________ μ<br />
* SNICS Channel 2 Source Box Thermocouple __________ μ<br />
<br />
'''IN TANDEM VAULT: LOW ENERGY END'''<br />
<br />
LE Cryopump:<br />
* Head Temperature _____ K <br />
LE Vacuum: <br />
* Penning Gauge ____ TORR<br />
<br />
'''IN TANDEM VAULT: HIGH ENERGY END'''<br />
<br />
HE Cryopump:<br />
* Head Temperature _______ K<br />
<br />
HE Vacuum: <br />
* Penning Gauge 1 ______ TORR<br />
* Penning Gauge 2 ______ TORR<br />
<br />
TR 1-90 degree Magnet Penning gauge: _________ TORR <br />
TR 1-90 degree Magnet Cryopump<br />
* Head Temperature _________ K<br />
<br />
Linac Beam Line Penning gauge: __________ TORR<br />
<br />
<br />
Switching Magnet Penning gauge ________ TORR <br />
<br />
<br />
Additional Notes:</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=2035Ion Sources2023-09-30T13:55:19Z<p>Iwiedenhoever: /* General */</p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment while at high voltage potential causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# Turn on the pre-accelerator high-Voltage supply <br />
# In the control room increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power supply cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rods extending out of the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Pre-accelerator high-Voltage supply". <br />
# '''Lockout the power plug using a lockout device available in the control room cabinet''', following the instructions for "SNICS Ion source lockout". and filling an entry in the lockout log book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the lockout-tagout book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator high-Voltage supply power cord and plug it in, noting the "unlocked" state in the "lockout tagout" log book located in the control room. <br />
# Turn the pre-accelerator high-Voltage supply on and push the green "High Voltage" button. <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lockout the power plug labeled "Pre-accelerator high-Voltage" using a lockout device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lockout tagout logbook. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''lockout devices''', and attach a '''tag''' to them. <br />
# Write a corresponding entry in the lockout tagout log book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# '''Remove the lockout device''' on the "Gap lens" power supplies and plug it into power outlets marked "Vacuum interlocked". <br />
# Remove the lockout tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the control-rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV with the control-rod from outside the cage. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages with their respective control-rods. <br />
# '''Remove the lockout device''' on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=2034Radiation Safety2023-09-30T13:11:46Z<p>Iwiedenhoever: </p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas. The operator in charge has to verify that no person remains in the area before the doors are closed and the door interlock <br />
alarms in the control room are activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below 2.0 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. Make entry to the log book with the results of the radiation levels and of the fact that access to the area was granted and to whom. <br />
If radiation levels are above these limits, access to the areas is prohibited, all persons have to leave the affected areas and the operator in charge has to verify that no person remains in the areas before the doors are closed and the door interlock alarm in the control room is activated. The same rules as in 3.a apply in the case of access doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.0 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed, the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.0 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.0 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.0 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the beacon will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.0 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
The dose limit for access to radiation areas at the Tandem-Linac lab is set at 2.0 mREM/h. <br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any quarter.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=2029Radiation Safety2023-09-27T11:14:38Z<p>Iwiedenhoever: </p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas. The operator in charge has to verify that no person remains in the area before the doors are closed and the door interlock <br />
alarms in the control room are activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below 2.0 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, all persons have to leave the affected areas and the operator in charge has to verify that no person remains in the areas before the doors are closed and the door interlock alarm in the control room is activated. The same rules as in 3.a apply in the case of access doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.0 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed, the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.0 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.0 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.0 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the beacon will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.0 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
The dose limit for access to radiation areas at the Tandem-Linac lab is set at 2.0 mREM/h. <br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any quarter.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=FSU_Fox%27s_Lab_Wiki&diff=2028FSU Fox's Lab Wiki2023-09-27T11:08:03Z<p>Iwiedenhoever: /* Accelerator Operation Procedures */</p>
<hr />
<div><br />
= Introduction =<br />
<br />
*This is the wiki for all details about FSU [[John D Fox]]' Lab for nuclear physics.<br />
*The original manual can be found in [[:File:FoxManual20200415.pdf]].<br />
*This wiki is <b><span style="color:red">OPEN TO PUBLIC</span></b>. Any confidential material should put in <b>[http://elog.physics.fsu.edu elog]</b>.<br />
*For [https://www.lsu.edu/physics/research/nuclear-physics.php Louisiana State University] users, please see [https://fsunuc.physics.fsu.edu/elog/202204_SPS_Blocker/2 this elog] for entering the [[Fox's Lab Network]].<br />
*New account may like to see the wiki syntax in [[Wiki_Edit_Cheat_Sheet | here]].<br />
= Accelerator Operation Procedures =<br />
● [[Radiation Safety]]<br />
<br />
= Hardware = <br />
{|style="width: 100%;"<br />
|● [[Tandem Accelerator]] || ● [[LINAC]]<br />
|-<br />
|● [[SF6 Gas Handling System]] || ● [[Vacuum Systems]]<br />
|-<br />
|● [[Water Cooling System]] || ● [[He refrigerator]]<br />
|-<br />
|● [[Computers Network]] || ● [[Hardware/Cable Changes for Switching Target Rooms]]<br />
|-<br />
|● [[Ion Sources]]: This includes the [[Ion Sources#Sputter Source|Sputter Source]] and [[Ion Sources#RF Source|RF Source]] || ● [[Target Lab]]<br />
|-<br />
|● [[RESOLUT]]: In-flight radioactive beam facility<br />
|-<br />
|● [[Triton Beam Project]]: [[Triton Injector#Triton Injector|Triton Injector]]<br />
|}<br />
<br />
== Detector stations ==<br />
<br />
{|style="width: 100%;"<br />
|● [[ANASEN]] || ● [[CATRiNA]]<br />
|-<br />
|● [[Clarion2]] || ● [[ENCORE]]<br />
|-<br />
|● [[Gamma Station]] || ● [[RESONEUT]]<br />
|-<br />
|● [[Split-Pole Spectrograph]]<br />
|-<br />
|● [[Penning Trap]]<br />
|}<br />
<br />
== DAQ systems==<br />
{|style="width: 100%;"<br />
|● [[Pixie16 digitizer]] || ● [[CAEN digitizer]] and [[Specter]]<br />
|-<br />
|● [[Mesytec]] || ● [[NSCL DAQ]] / [[NSCL SpecTcl]]<br />
|}<br />
<br />
= Software & Resources = <br />
<br />
{|style="width: 100%;"<br />
|◆[[Online Resources]]: Web server, Elog, Grafana, Wiki, InfluxDB || ◆[[Data Server]]<br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/git/explore/repos Git repository] by Gitea || ◆[[Github repositories]] <br />
|-<br />
|◆[[SSH tunneling]] || ◆[[VNC viewer]]<br />
|-<br />
|◆[[Slack Channel]] || ◆[[gnuscope]]<br />
|-<br />
|◆[[SolidWorks]] || ◆[[Online Analysis]]<br />
|-<br />
| ◆[[Raspberry Pi Camera]] || ◆[[Python Iseg HV controller]] <br />
|-<br />
|◆[https://fsunuc.physics.fsu.edu/research/publication_list/ List of Publications]<br />
|}<br />
<br />
= Layout of the Laboratory =<br />
{|<br />
|[[File:Lab Model.png|450px|frameless|none]] || [[File:JohnDFoxLayout.png|550px|frameless|none]] <br />
|}<br />
<!--[[File:NRBbasement.png|1000px|thumb|none]]--><br />
<br />
= External Collaborations = <br />
<br />
* [[LSU Collaboration]]<br />
* [[ORNL Collaboration]]<br />
* [[TRIUMF Collaboration]]<br />
* [[FRIB FDSi e21062]]<br />
* [[FRIB SOLARIS Collaboration]]<br />
* [[ANL MUSIC Collaboration]]<br />
<br />
= Past Experiments =<br />
<br />
[[List of Past Experiments]]<br />
<br />
= Other Resources =<br />
<br />
* [[Help Call List for Evenings, Weekends, Holidays]]<br />
<br />
* [[Laboratory Infrastructure]]<br />
<br />
* [[Wiki Edit Cheat Sheet]]<br />
<br />
* [[Guide for using this wiki]]<br />
<br />
* [https://www.qr-code-generator.com/ QR code generator]<br />
<br />
* [[Weekly Tandem Maintenance]]<br />
<br />
* [[Source Sign Out Sheet]]<br />
<br />
= Contacts = <br />
<br />
{|<br />
| for accelerator ||: Lagy Baby mailto:lbaby@fsu.edu <br>: Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu<br />
|-<br />
| for vacuum ||: Powell Barber mailto:pbarber@fsu.edu<br />
|-<br />
| for ion sources || : Brian Schmidt mailto:bschmidt@fsu.edu<br />
|-<br />
| for LINAC || : David Spinger mailto: dspingler@fsu.edu<br />
|-<br />
| for IT and DAQ ||: Ryan Tang mailto:rtang@fsu.edu<br />
|-<br />
|}</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Tandem_Accelerator&diff=2027Tandem Accelerator2023-09-27T11:07:11Z<p>Iwiedenhoever: </p>
<hr />
<div>[[File:TandemVault.png|500px|thumb|right]]<br />
<br />
{{Warning | NEEDS PROOF READING }}<br />
<br />
= Tandem Beamline SF6-Gas Security Ball Valves =<br />
<br />
<br />
Each beam line exiting the Tandem has a large diameter, pneumatically actuated Worcester Controls ball valve that will automatically close under normal operating conditions if a pressure rise on the order of in. of Hg is detected on the Tandem side of the valve. Because the Tandem is filled with SF6 at 85 psi and the accelerator tubes and beamline are under vacuum a failure of an O-ring seal, accelerator tube metal to glass bond or any major compromise of vacuum integrity within the machine could have catastrophic results. The intention of the valves are two fold. One is to contain the gas to prevent its loss, a $70,000 investment. The other is to prevent damage to the equipment on the beam line that is designed to withstand the implosive forces of vacuum and not the explosive 85 psi tank pressure.<br />
<br />
An Edwards High Vacuum Ltd. pressure switch is located on the L.E. end of the Tandem beam line to sense the fault condition along with a 30 in. Hg to 60 psi compound gauge to monitor the tube vacuum/pressure in the range where penning gauges and thermocouples are not usable. The control panel is in the vault L.E. electronics rack below the beamline, and the key switch for disabling control of the ball valves is kept in the red case underneath the Control Room console. When the vault control panel is in the unprotected key switch position the ball valves can be opened and closed at will. In the protect position the ball valves can only be opened when the beamline pressure switch is closed. An LED on the control panel, labeled sensor contact, will illuminate when the switch is closed.<br />
<br />
The Gas Security Ball valve controller is integrated with the Tandem Pelletron interlock circuit. A closure of the ball valve either manually or due to a failure of the vacuum integrity is sensed by the Ball valve controller and results in the Pelletron charging supplies being interrupted via the interlock panel.<br />
<br />
Because they are pneumatically controlled, a loss in compressed air service will result in the valves closing. There will be no electric circuit indication such as the sensor contact LED being off or the Pelletron H.V. supplies being tripped off. If beam transmission through the machine is nil, investigating the ball valves themselves will allow ascertaining the valves’ state. On top of the pneumatic actuators are square posts that turn with the ball valve, the valves are open if the small silver stud on one of the flats is facing West.<br />
<br />
= Tandem Beamline Vacuum Protection System =<br />
<br />
[[File:BeamLineControlPanel.jpg|500px|thumb|right]]<br />
<br />
The logic and status chassis for the Tandem Vault beam lines is above the switching magnet power supply, North of the H.E. vault shield door. There is a status panel also in the Control Room above the beamline devices panel (figure 4). The L.E., H.E., Sputter Source and Polarized Source vacuum indications are displayed in the Control Room also.<br />
<br />
Each Tandem beamline fast valve has a dedicated control box and penning gauge except for the 90◦ magnet which has a penning gauge but no fast valve to control. Each controller has a “good vacuum” output signal that is “anded” together in the logic chassis with the other controllers. If any of the five penning gauge controllers detect a vacuum incident, all four of the fast valves will close and the Tandem Pelletron charging H.V. supplies will be disabled.<br />
<br />
The Tank Gas Security Ball Valve Controller is also “anded” with the beamline penning gauge controllers in the logic chassis and an LED indication for the ball valves status is provided. If either the L.E. or H.E. Gas Security ball valve is closed, the Pelletron H.V. charging supplies are disabled. If the ball valves have closed on their own something could be severely wrong and a staff member familiar with this system should be consulted before they are reopened. More information about the Gas Security ball valves can be found in Sec. 18.<br />
<br />
The source penning gauge is not included in the “anded” logic to close the beamline valves. The source penning gauge will close the source exit valve and turn off the preaccelerator H.V. supply if the ion source vacuum sufficiently degrades. The valve control boxes for the two sources are different, so, arbitrary interchanging of the boxes cannot be done.<br />
<br />
The fast valve control box/penning gauge controllers themselves do have many common features. The valve control boxes can be used to open and close a valve at will in the unprotected mode (no vacuum consideration). In the protected mode, the valve can only be opened if the vacuum at the associated gauge head is better than the chosen set point, approximately 5 x 10−6. A controller that has sensed a vacuum excursion will have a flashing LED; to rearm the protection circuit and open the valve(s) that has tripped close, depress the push button reset switch on the front panel of that controller, the LED should stop flashing. Be cautious with the beamline valves: if all the controllers sense a good vacuum and all valve switches are in the open position, all four fast valves will open simultaneously. If this is not desired, place the valve control box switches to close, reset the tripped penning gauge controller, and then open the valves individually. If a penning gauge controller is out of service or it is desirable to prevent a controller from closing the beam line valves, it can be overridden at the logic panel by placing the switch indicated for that controller in the override position. The Ball valves should only be overridden after a staff member familiar with this system has been consulted.<br />
<br />
= Tandem Pelletron Interlock Panel =<br />
[[File:PelletronInterlockPanel.png|700px|frameless]]<br />
<br />
<br />
To prevent dangerous operation of or damage to the accelerator an interlock circuit is employed. The status of the various interlock switches is displayed at the interlock panel. The switches and their status are in a serial configuration therefore should one interlock not be closed all others “down stream” will also indicate an open situation and the LEDs will be extinguished. The panel layout is natural in that all the LEDs to the right of the offending switch will be out; once that interlock is satisfied its LED will illuminate and the rest to its right should also shine if the switches are closed. The interlock circuit, depending upon which switch opens up, will either turn off the charging supplies or both the charging supplies and the chain drive motors. All the interlocks up to and including the tank pressure switch will disable both the chain drives and power supplies, the remaining only affect the charging supplies.<br />
<br />
<br />
There are nine LEDs on the Tandem Pelletron Interlock Panel, see figure 10. A brief description of each interlock or LED indication in the order that they are appear on the panel follows.<br />
<br />
'''Status Power''': This lamp will be lit if the power switch key is turned to on and the 12V dc supply used for the series circuit is present.<br />
<br />
'''Control Power''': This lamp indicates AC power is present within the chassis when the switch key is turned to on.<br />
<br />
'''HE Tank Door''': A push button switch is mounted on the Tandem High Energy Tank Door to sense when the door is fully rotated closed.<br />
<br />
'''LE Tank Door''': A push button switch is mounted on the Tandem Low Energy Tank Door to sense when the door is fully rotated closed.<br />
<br />
'''LE Pendulum''': A push button switch is mounted to the LE drive sheave assembly to sense excessive Pelletron chain stretch or failure. <br />
<br />
'''HE Pendulum''': A push button switch is mounted to the HE drive sheave assemblyto sense excessive Pelletron chain stretch or failure.<br />
<br />
'''Tank Pressure''': A pressure switch is mounted to the Tandem pressure vessel to ensure a minimum pressure of 35 psi is established before the Pelletron chain is started.<br />
<br />
'''Vac Ball Valves''': This interlock is closed when the Tandem Beam Line Valve Protection System detects no tripped penning gauge controller or beamline SF6 protection ball valve closure. A separate status panel is present in the Control Room for this beamline protection system and an override/status panel is located in the Tandem Vault to the North of the HE door. A more detailed description of that circuit can be located through the Table of Contents.<br />
<br />
'''TPS OV/UV''': The Terminal Potential Stabilizer supplies a relay that relaxes whenever the terminal voltage varies beyond a set percent of the value displayed at the terminal voltage reference potentiometer. This TPS feature must be enabled to trip the interlock panel for an out of range voltage excursion.<br />
<br />
Should a condition arise where disabling the Tandem Pelletron Interlock Panel is desired, such as a tank opening, an override switch is located in the back of the panel chassis. It is accessible from behind the electronics racks.<br />
<br />
= Terminal Potential Stabilizer =<br />
<br />
The Terminal Potential Stabilizer (TPS) consists of five main components: Controller Unit, Generating Voltmeter (GVM), Analyzing Slits, Capacitive Pick-Off Plates (CPO) and the Corona Probe.<br />
<br />
The Controller as is suggested, controls the terminal voltage by comparing signals from the GVM, slits and the CPO to produce a correction signal that modulates the current flowing to the terminal from the corona probe.<br />
<br />
The GVM is mounted on the tank wall of the Tandem opposite the terminal. A four bladed rotor spins at 3450 rpm over a surface divided into eight segments each the size of one blade. As the rotor spins it uncovers some segments and exposes them to the terminal voltage which results the segment charging to a voltage proportional to the terminal voltage. When the segment is again shielded by the rotor, charge will drain away. The signal produced by the GVM is conditioned locally by an amplifier and routed to the controller.<br />
<br />
The analyzing slits are in the typical configuration, downstream of the 90◦ analyzing magnet, parallel to the pole face plane and opposite each other on the exiting beamline. They are adjustable with micrometer style knobs for each and are electrically isolated. Beam being bent around the 90◦ magnet impinges upon the slits creating a signal proportional to the beam it senses. The signals from the slits are conditioned locally by an amplifier and routed to the controller.<br />
<br />
There are two CPO plates in the Tandem that are mounted on the tank wall opposite the terminal. These plates are electrically isolated and sense fluctuations of terminal voltage at frequencies above those detectable by either the slits or the GVM. Two plates are used to cancel out physical movement of the column that would be detected as a voltage fluctuation by a single plate as the separation between the terminal and plate changes. The signal from the CPO plates is conditioned locally by an amplifier and routed to the controller.<br />
<br />
The corona probe is also mounted on the tank wall opposite the terminal. The probe is mounted on a shaft that can be driven to different distances to the terminal depending on the terminal operating voltage. The end of the probe consists of a shell with 12 needle points extending slightly beyond the polished shell surface. The voltage on the needle points determines the flow of electrons to the positively charged terminal. Modulating this flow of electrons is done by the Controller based on the information provided by the GVM, slits and the CPO.<br />
<br />
The typical operation of the system is described to assist the operator in understanding how the system maintains terminal stability. The description is not intended to be used for bringing up the terminal voltage as it excludes the Charging Controllers and positioning of the corona probe. Feedback or modulation of the probe current will take place only when the TPS Control Gain is turned up. The Controller has three possible modes of operation namely GVM, Slit or Auto. The Auto mode allows the TPS to switch into one of the other two modes depending whether the terminal voltage is approximately 50 KV off of the controller Terminal Voltage Reference Potentiometer setting and/or beam current above 10 nanoamperes is sensed by the analyzing slits. Typically the Controller is in the Auto mode.<br />
<br />
With less than 10 nanoamperes of beam on the analyzing slits, the Tandem will be in GVM mode. The correction signal in this mode is derived by comparing the front panel Terminal Voltage Reference Potentiometer setting to the GVM measurement of actual terminal voltage. The CPO signal is added to this to produce the error signal that ultimately modulates the corona probe voltage. The operating voltage of the probe needles is proportional the Grid Bias indicated on the Controller chassis. In this mode the terminal voltage will track the Reference Potentiometer setting and allows one to scan the terminal voltage until beam strikes the analyzing slits.<br />
<br />
With beam on the slits and the GVM and Terminal Voltage Reference Potentiometer in relative agreement the TPS Controller will switch to Slit mode. The controller compares the current striking one slit to the other to create an error signal that attempts to keep the measured current balanced. The slit on the inside of the analyzing magnet bend is the Low Energy (LE) slit and the one on the outside is the High Energy (HE) slit. If an excess of beam is detected by the LE slit an error signal is produced by the TPS that will reduce the probe electron current flowing to the terminal causing the terminal voltage to rise which will bring more beam current to bear on the HE slit until a balanced situation is again reached. Like the GVM mode, the CPO signal is added to modulate the probe current. In this control mode adjusting the Terminal Voltage Reference Potentiometer has no effect until the disagreement with the GVM causes the TPS to revert to GVM mode. When the TPS is in Slit mode the Reference Potentiometer should be adjusted to agree with the GVM indication.<br />
<br />
<br />
= Operating Instructions for the Tandem Pelletron = <br />
<br />
== To Turn the Tandem Pelletron On ==<br />
<br />
# Set the TERMINAL POTENTIAL STABILIZER CONTROL MODE to AUTO and turn the CONTROL GAIN and CPO GAIN to zero.<br />
# Turn on the LOW ENERGY CHARGING CONTROLLER AND THE HIGH ENERGY CHARGING CONTROLLER by turning their key switches CW to the ON position. To start the charging chains lift the momentary CHAIN switch to<br />
# the ON position for each CONTROLLER. After approximately ten seconds the lamp below the switch will illuminate indicating the chain is up to speed.<br />
# Set the corona probe BIAS CURRENT to 35 microamps on the TPS<br />
# Set the corona probe to the approximate position indicated in the table for the desired terminal potential.<br />
# Set the GVM REFERENCE VOLTAGE knob to the correct voltage (e.g. 8 MV would be “0800”).<br />
# Ensure the TERMINAL CHARGE POTENTIOMETER on the LOW ENERGY CHARGING CONTROLLER is turned down to zero, CCW.<br />
# Turn both POWER SUPPLY switches to ON on the CHARGING CONTROLLERS. Their indicator lamps should glow.<br />
# While watching the corona probe GRID voltage, carefully increase the charge carried by the chains by turning the TERMINAL CHARGE POTENTIOMETER CW. Turn the TERMINAL CHARGE POTENTIOMETER until the GVM/TV<br />
# Balance indicates approximately zero or the GRID voltage has reached -9V. If any time the GRID voltage reading goes beyond -1OV, run the corona probe out to reduce it. Fine tune the corona probe position and the up-charge so that the GRID voltage reads approximately -9V when the desired terminal voltage is reached.<br />
# Enable the OVER/UNDER VOLTAGE PROTECTION and set both the CONTROL GAIN and CPO GAIN to 5.<br />
# Readjust the corona probe if necessary to attain -9V; do not exceed this voltage on the GRID.<br />
# Set the 90◦ magnet to the appropriate field and put beam through the Tandem. If the TPS does not switch to the SLIT CONTROL MODE and lockup on a beam the GVM REFERENCE VOLTAGE knob can be adjusted slightly to scan for the<br />
# beam; only a slight adjustment should be necessary.<br />
# With beam on the slits, and the TPS in SLIT CONTROL MODE adjust the TERMINAL CHARGE POTENTIOMETER so that the Slit Balance meter reads zero, and retrim the corona probe position, if necessary, to get -9V on the GRID.<br />
# Adjust the GVM REFERENCE VOLTAGE knob so that the GVM/TV Balance meter indicates approximately zero.<br />
<br />
<br />
== If there is a spark ==<br />
<br />
The OVER/UNDER VOLTAGE PROTECTION interlock on the TERMINAL POTENTIAL STABILIZER panel will be tripped and the red LED should be lit. The CHARGE CONTROLLER POWER SUPPLIES are disabled by this protection circuit, however, the chains will continue to run.<br />
# Turn the CONTROL GAIN and CPO GAIN to zero<br />
# On the LOW ENERGY CHARGING CONTROLLER turn the TERMINAL CHARGE POTENTIOMETER back to zero.<br />
# Reset the TPS OVER/UNDER VOLTAGE PROTECTION interlock by depressing the momentary switch.<br />
# Turn up the TERMINAL CHARGE POTENTIOMETER until the previous terminal potential is reached; watch for signs of conditioning.<br />
# Check that the GRID voltage reads approximately -9V .<br />
# Set the CONTROL GAIN and CPO GAIN to 5.<br />
# Put beam through the Tandem Pelletron and adjust the TERMINAL CHARGE POTENTIOMETER to center the Slit Balance meter.<br />
# Enable the OVER/UNDER VOLTAGE PROTECTION circuit.<br />
<br />
== To TURN OFF the Tandem Pelletron ==<br />
# Disable the “TPS OVER/UNDER VOLTAGE PROTECTION” and turn the “CONTROL GAIN” and “CPO GAIN” to zero.<br />
# On the Charging Controller Turn the “TERMINAL CHARGE POTENTIOMETER” back to zero and turn off the CHARGING POWER SUPPLIES at the toggle switch. Depress the momentary switch for the chains to turn them off and then<br />
# turn the panel key switch to off.<br />
<br />
== To Change the Terminal Potential ==<br />
<br />
# Disable the TPS OVER/UNDER VOLTAGE PROTECTION and turn the CONTROL GAIN and CPO GAIN to zero.<br />
# If the terminal potential is to be decreased, reduce the CHARGE CONTROLLER TERMINAL CHARGE POTENTIOMETER until the TPS displays the TERMINAL VOLTAGE desired. Typically the terminal voltage will drop as the corona probe is run in requiring increases of chain current. Adjust the corona probe position and the TERMINAL CHARGE POTENTIOMETER to get approximately -9V on the GRID.<br />
# If the terminal potential is to be increased, run the corona probe out to the approximate position indicated in the table for the desired terminal potential.<br />
# While watching the corona probe GRID voltage, carefully increase the CHARGE CONTROLLER TERMINAL CHARGE POTENTIOMETER. Increase the TERMINAL CHARGE POTENTIOMETER until the TPS displays the TERMINAL VOLTAGE desired or the GRID voltage has reached -9V. If at any time the GRID voltage reading goes beyond -1OV, run the corona probe out to reduce it. Readjust the corona probe position and the TERMINAL CHARGE POTENTIOMETER so that the GRID voltage reads approximately -9V at the desired terminal voltage.<br />
# Adjust the GVM REFERENCE VOLTAGE knob so that the GVM/TV Balance Meter indicates zero.<br />
# Enable the TPS OVER/UNDER VOLTAGE PROTECTION and turn the CONTROL GAIN and CPO GAIN to five.<br />
# Readjust the corona probe if necessary to attain approximately -9V on the GRID; do not to exceed this voltage.<br />
# Set the 90◦ magnet to the appropriate field and put beam through the Tandem Pelletron.<br />
# If the TPS does not switch to the SLIT CONTROL MODE and lockup on a beam the GVM REFERENCE VOLTAGE knob can be adjusted slightly to scan for the beam; only a slight adjustment should be necessary.<br />
# With beam on the slits, and the TPS in SLIT CONTROL MODE adjust the TERMINAL CHARGE POTENTIOMETER so that the Slit Balance meter reads zero; retrim the corona probe position, if necessary, to get approximately -9V on<br />
# the GRID.<br />
# Adjust the GVM REFERENCE VOLTAGE knob so that the GVM/TV Balance meter indicates approximately zero while the TPS is in SLIT CONTROL MODE.<br />
<br />
== Extended Tandem Pelletron Shutdown ==<br />
<br />
If the current experiment has concluded and machine downtime is expected, the following list should be followed. Ensure a log sheet has been filled out that includes all the beamline devices (figure 4) settings, Faraday cup currents, Tandem parameters,...etc.<br />
<br />
# Return beam to the L.E. Faraday cup.<br />
# Turn the Terminal Potential Stabilizer Control and CPO Gain to zero, Disable the over/under voltage protection.<br />
# Turn the Terminal Charge Potentiometer on the Low Energy Charging Controller down to zero, CCW.<br />
# Turn both power supply switches to off on the Charging controllers.<br />
# Stop the charging chains by depressing the momentary chain switch to the off position for each Controller.<br />
# Turn off the Low Energy Charging Controller and the High Energy Charging Controllers by turning their key switches CW to the off position.<br />
## Turn down the supplies for these devices: <br />
## switching magnet, <br />
## 90◦ magnet<br />
## Target room quadrupoles and deflectors<br />
## accelerator quadrupoles and deflectors<br />
## L.E. beamline lens 2.<br />
# Close the hand valve before the Tandem 90◦ magnet.<br />
# Follow the source turn down instructions (Sec. ??).<br />
# Remove control power key if a tank opening is required.<br />
<br />
= Terminal Stripper Foil Changer = <br />
<br />
A change in terminal stripper foil is indicated by a decrease in beam transmission through the Tandem. To change the foil one of the two rocker switches on the foil changer panel in the Control Room should be depressed. The direction of movement, either forward (increment) or reverse (decrement) should be that which would bring a fresh foil into the beam path, consult the logbook for used foil information. Motion of the foil band will continue while a switch is pressed. When the direction of the foil change is reversed a considerable amount of backlash, inherent with magnetic couplings, will result in a longer period than for the initial foil change. Use the rocker switches to maximize beam transmission through the Tandem.<br />
<br />
The foil changer can be placed in an automatic change mode that allows the foil to be incremented or decremented to a preset number. On the foil changer panel is a thumb wheel numeric display that should be adjusted to indicate the desired foil number. A small toggle switch is located at the left corner of the display should be switched to the “ena.” (enable) mode. The preset push button should be depressed, the labeled LED below the display should light. Now depress the rocker switch that will allow the foil changer to either increment or decrement to the chosen value. Fine tuning of the foil will be required after the preset is reached. When finished with the preset function put the toggle switch back to the “dis.” (disable) position.<br />
<br />
The equipment employed in the changing of the foils consist of the control panel in the Control Room, a slosyn motor, a shaft encoder, control rod with coupling hardware to span the L.E. column and a magnetic coupling to transfer motion to the stripper foil band which resides in vacuum. Within the stripper foil housing are two bands of foils, 300 foils per band for a total complement of 600 foils. A description of the band changer can be found in Sec. 25. The foils are rotated into the beam path by the slosyn motor via a control rod spanning the L.E. column and terminating in the terminal. The 110 Vac slosyn motor is bidirectional and receives power from the Control Room via the L.E. bulkhead feedthrough BU 9, pins No. 5,6 and 7 (Increment, decrement and AC neutral respectively). The 3000 count shaft encoder is used for record keeping of the foil inventory. The encoder is coupled to the motor by a timing chain and a 10 to 1 reducing gear. The encoder signal is transmitted to a four digit counter LED display on the foil control panel via the L.E. bulkhead feedthrough BU 7, pins No. 4,5,6,7,8 and 9.<br />
<br />
= Terminal Foil Band Changer =<br />
<br />
The terminal band changer is actuated in the Control Room at the foil changer panel. A momentary three position switch is used along with a keyed enable switch in hopes of removing the uncertainty of knowing which band is in use and which band, if any, is exhausted. To adjust or change bands insert the key into the “Band Change Enable” slot and turn the key clockwise. The key is kept in the red box below the console.<br />
<br />
Ensure you are aware of what band is being used before making a change. Press and hold the appropriate toggle switch until beam on the HE cup drops off and then returns. Continue holding the switch and note the maximum beam current observed before the beam begins to fade again. Release the switch when the beam current begins to drop. Now fine tune the stripper foil by pressing the switch to move back towards the previous band position; release the switch when the previously observed maximum beam current returns to the HE cup. When satisfied with the band position, ensure the correct LED band indication is lit for the correct band by a short flip of the band changer switch. Turn the key counter clockwise to disable the band changer mechanism.<br />
<br />
This paragraph describes the details of the band changer mechanism. The Foil/Band changer electrical leads run out to the L.E. Tandem base plate and then internally via the bulk head feedthrough BU 9 on pins #2, 3 and 4. Inside the machine, behind the L.E. base plate aluminum cover, is the slosyn motor that drives the control rod whenever the enable key and momentary switch in the Control Room is closed. The control rod spans the length of the L.E. column and terminates in the terminal; the control rod is on the West side of the column and is above the accelerator tube. The control rod rotates a cam/microswitch assembly in the terminal that is capable of sensing the direction of rotation of the control rod. The microswitches energize a timer/relay once per revolution of the control rod (∼ 3 seconds) which in turn powers the motor that either lifts or lowers the end to the stripper foil housing for a preset interval. Movement of the stripper foils is achieved by a gimbaled pivot point on the housing allowing positioning of the foils at the beam end of the housing. The travel or pivot arc of the housing is limited by another set of microswitches that interrupts the band changer motor power when at the end of the adjustment range.<br />
<br />
<br />
= Letting the Accelerator Tubes Up to Dry Nitrogen =<br />
<br />
These instructions are specifically written for letting up the minimum beamline volume to gain access to the accelerator tubes and anything between the HE fast valve and the LE Gas Security Ball Valve – typically for a foil change. Puffs of gas or excessive gas flows must be avoided to protect the fragile stripper foils in the terminal of the Tandem. If access to additional beamline length is necessary, more pumps may need to be isolated and different valves closed.<br />
<br />
# In the Control Room turn down the lens and deflectors on the L.E. beam line.<br />
# Turn off the L.E. Buncher amplifier in the vault.<br />
# Turn power off to the L.E. and Cup 1 controllers before letting up the beam line to dry Nitrogen. Remove the lead from the L.E. cup that connects to the 300 V dc suppression battery.<br />
# Turn off the Low Energy and High Energy Penning gauge controllers.<br />
# Pump the beamline through the sputter source. Put the SNICS source in the Idle mode (consult Sec. 9 and place the exit, baffle and backing valves in the unprotected mode. Ensure the source exit valve and the others are open.<br />
# Close the Low Energy cryopump gate valve.<br />
# Close the Low Energy Gas Security Ball Valve. With the key kept under the console in the Control Room, switch the valves at the vault control panel to the unprotected position to prevent the High Energy Ball Valve from automatically closing when letting up the tubes. Additional information on the Ball Valves can be located in Sec. ??.<br />
# Close the H.E. fast valve to maintain a vacuum in the down stream beamline. Ensure the hand valve before the 90◦ magnet is open.<br />
# Close the High Energy cryopump valve.<br />
# Close the LINAC entrance valve to the North of the Tandem 90◦ magnet.<br />
# The valves and gauges necessary for letting up the tubes are at the H.E. end where the beamline exits the Tandem. A manifold with copper tubing is on the East side of the beam line. Slowly open the 1/4” ball valve exiting the manifold and in series with the 0-50 L/min Air flow gauge so that the tubes can be let up to Nitrogen. Ensure the needle valve at the Nitrogen flow gauge is closed. The compound gauge should indicate vacuum when the valve is opened.<br />
# Adjust the flow gauge needle valve so that the gauge at the inlet is at 29 in. of Hg and note the flow rate; it should be about 25 L/min. Periodically adjust the flow rate to maintain that which was previously noted. The gas will need to flow for ∼ 1 hour to fill the void.<br />
# When the tubes are at atmosphere or slightly above, close the flow gauge valve and, if necessary, slowly bleed off the excess pressure by slowly opening the pump out port 1 1/4” ball valve that is attached to the copper manifold.<br />
# Depending on the circumstances it may be preferable to allow a small flow of Nitrogen to reduce the quantity of air that will migrate into the tubes while they are open. Open the flow gauge slightly after the beamline vacuum seal is broken.<br />
<br />
= Pumping Down the Accelerator Tubes =<br />
<br />
After all the broken seals are remade the tubes are ready to be pumped out. An oil free vacuum pumping system must be employed when pumping down the tubes. Do not use an oil sealed mechanical pump as they can allow oil mist to back flow into the accelerator tubes. A Carbon Vane pump followed by a Sorption pump is sufficient. To protect the fragile foils, puffs of gas or excessive gas flows must be avoided so use care. Open valves slowly to begin the pumping.<br />
<br />
# The port for pumping down the tubes is in series with the 1 1/4” ball valve attached to the manifold at the HE beamline. Attach the pumping station to the end of the 1” copper pipe port and evacuate the pipe up to the closed 1 1/4” ball valve. Slowly begin opening this ball valve and stop as soon as either the pumping station vacuum gauge indicates a pressure rise or the vacuum pump audibly responds to a gas load. Slowly open the ball valve more as the vacuum continues to improve in the tubes. The valve should be completely open at ∼ 25 in. of Hg.<br />
# Experience has shown that the vacuum in the trapped volume of the closed L.E. ball valve will degrade during the period the valve is closed. When the tube/beamline vacuum is at 100 millitorr open the ball valve and allow the gas load to be pumped by the Sputter Source diffusion pump.<br />
# Switch the gas security ball valves at the vault control panel to the protected position with the key switch. Put the key back in the red box under the console in the Control Room.<br />
# After the tube vacuum has dropped to 50 millitorr close the 1 1/4” manifold ball valve and open the both cryopump gate valves. Remove the pumping station and return it to where it was found.<br />
# Turn on the Low Energy and High Energy Penning gauge controllers.<br />
# Turn the L.E. and Cup 1 controllers back on and reconnect the 300 V dc suppression battery coax cable to the L.E. cup.<br />
# Open the HE fast valve and close the hand valve before the 90◦ magnet.<br />
# Place the SNICS source exit, baffle and backing valves back in the protected mode and close the exit valve.<br />
<br />
= Venting the Tandem to Air = <br />
<br />
See [[SF6_Gas_Handling_System#Venting_the_Tandem_to_Air | Venting the Tandem to Air]]<br />
<br />
<br />
= Tandem Pressure Vessel Sulfur Hex Alarm Circuit Description =<br />
The alarm has been set to trip at 75 PSIG and is intended to safeguard the gas inventory while in the Tandem. Should a substantial (not just cold gas) change in the pressure be noted or if the panel alarm begins to annunciate immediately call a member of the staff. Not only is the SF6 inventory expensive ($70,000) but also is very heavy and will displace air which could possibly lead to asphyxiation. Do not linger in enclosed areas common to the gas leak. Sulfur Hexaflouride, SF6, is, however, nontoxic.<br />
<br />
The alarm can be muted at the front panel, but the visual LED will continue to flash as long as the pressure is below the set point value. For extended tank openings the power switch can be turned off.<br />
<br />
The pressure and temperature transducers are mounted to the flange on the southernmost top tank port. The circuit box adjacent to the flange should be turned on and plugged into a source of 110Vac. The transducers’ output is directed to the Control Room panel for display. Pressures below atmospheric are indicated by a negative sign with -14.8 psi being the lower limit of the transducers’ operating range.<br />
<br />
The tank pressure is also indicated by two Bourdon tube, mechanical pressure gauges and a Varian 501 Thermocouple gauge located at the H.E., West side of the pressure vessel. These gauges are independent of the alarm circuit. The error between the pressure indications in the Control Room with some of the others can be as high as 11%.<br />
<br />
===To reset the trip point to some other value, follow this procedure:===<br />
# At the back of the Pressure Vessel panel is a circuit board with a toggle switch position labeled calset; move the switch to that position. While observing the front panel pressure indication, adjust the cal potentiometer until the desired pressure at which to trip is displayed.<br />
# Also on the circuit board is a potentiometer labeled trip; adjust this potentiometer until alarm sounds and the front panel LED is flashing.<br />
# Place the toggle switch in “1.” back to the normal position. The panel pressure display should again indicate the current tank pressure.<br />
<br />
= Voltage-Conditioning the Tandem =<br />
<br />
After the machine has been opened for an extended period it is often noted that the machine will not return to the previously reached voltages and run stability. Letting up the accelerator tubes to atmospheric pressure for installation of new equipment, replacement of the stripper foil supply or other work also contributes to the degradation of the voltage holding capability of the machine. Preferably, the required terminal voltage for the experiment subsequent to a tank opening will be somewhat less than those reached previous to the opening. Regardless of the voltage requested, it should be assumed that some conditioning will take place and some care should be taken when first bringing up the terminal voltage. Also, the conditioning should be carried out until a voltage of at least 250KV over the experimenter’s requested voltage is attained. As the machine conditions, the required charging current to attain a specific voltage will typically decrease as corona sites on the column and other high voltage surfaces begin to dissipate allowing more current to flow through the resistance grading.<br />
<br />
The machine should be set up to condition by first withdrawing the corona probe to the tank wall. The H.E. faraday cup should be inserted and the beam current integrator set to measure picoamperes of cup current. The integrator upper limit alarm should be adjusted to mid scale so that meter excursions will sound the alarm. The Capacitiv Pick Off (CPO) trace should be displayed on an oscilloscope as well as recorded by the chart recorder. Since the machine is being conditioned the Terminal Potential Stabilizer (TPS) feedback is not necessary when charging the terminal so the Control and CPO Gains should be kept at zero. The TPS is, however, used for monitoring the Terminal Voltage and the chain charging trip feature it allows should be employed. By zeroing out the GVM error with the Terminal Reference Potentiometer, the increase in terminal potential for a fixed upcharge setting can be displayed as the “error” grows, but keep in mind the under/over protection circuit set point may be reached.<br />
<br />
Evidence of conditioning below 6MV is not common and voltage stability problems at this potential (sparking) are indicative of greater problems and a tank opening may be necessary. In general, any voltage instabilities associated with the terminal can be considered signs of conditioning; whether or not the voltage stability improves or persist, short of a mechanical/electrical failure, determines the length of the conditioning period and its success. At higher voltages the instabilities associated with conditioning become more evident. Since the capacitive energy residing in the charged terminal and column is strongly dependent on the voltage (CV2/2), more caution should be used when conditioning at higher voltages as the discharges become more destructive. When heavy conditioning begins to occur, maintain the current voltage until the conditioning events begin to subside. Voltage increases in steps of 200KV is suggested. If concern that damage is being done to the accelerator while attempting to condition (excessive sparking for example), please err on the side of caution and consult the staff.<br />
<br />
=== INDICATIONS OF CONDITIONING ===<br />
# Voltage instabilities indicated by the CPO either at the oscilloscope or the chart recorder.<br />
# Current indications by the beam current integrator.<br />
# Fluctuations of the terminal voltage indication by the TPS that are fast and greater than 20KV.<br />
# Sparking of the machine, may or may not be audible, but will usually trip the under/over protection circuit. There are in general three types of sparks. Tank and Column sparks both occur in the SF6 gas. The first is a discharge between the column and the tank wall and the other is along the column structure. Tube sparks occur within the evacuated space of the accelerator tubes and across tube electrode/insulators gaps.<br />
# Vacuum fluctuations at either the H.E. or L.E. end of the machine as indicated by the control room penning gauge meters.<br />
# Radiation emissions from the machine as indicated by the control room gamma/xray meter. Should these be in short bursts separated by even longer intervals and appear to be subsiding, then maintaining that voltage and waiting for improved stability is the suggested course of action. However, should the radiation persist at levels greater than 10 mREM/h and be steady, the machine should be turned off and the staff notified.<br />
<br />
= Power Failure Procedures =<br />
<br />
When the mains fail the emergency generator should start automatically. If the emergency lights come on, the generator is running correctly. The changeover breaker should switch automatically and restore power to all pump circuits. If this does not occur, the change over breaker, located on the West wall of the accelerator vault between the L.E. door and the sink, should be assisted with a 2-by-4. Note: In the emergency-power position, the central arm should be down.<br />
<br />
=== When emergency power is available at the pumping stations a number of things should be checked ===<br />
<br />
# Check that the recirculating pump, located just to the South of the L.E. door in the accelerator vault, is running. Restart if necessary. See [[Water Cooling System]].<br />
# Check that source pumping stations are operating normally. Restart pumps and reopen valves as necessary.<br />
# Check the turbo pump at the H.E. end, it may have tripped and be coasting down. It should be restarted.<br />
# Check [[Vacuum_Systems#Cryopump_Based_Stations|Cryopump]]. If the supply was only interrupted for a few seconds the compressors will restart automatically, but the input and output pressures will remain the same for approximately one minute; then the unit will switch and normal pressures will be reestablished. When this occurs the coldhead will restart and the vibration of this motion will be felt at the cold head. If the power is off long enough for the pump to start to warn and outgas, it will have to be started again. See the section 4 for cryopump head regeneration.<br />
# The pumps in the target room should be checked to ensure that they are running normally. Restart or close off as necessary.<br />
# When mains voltage is restored the changeover breaker will wait a short time, to ensure that the supply will probably remain on, and then will automatically change over and the emergency generator will shutdown. If the breaker hangs up it can be assisted up with the 2-by-4. When the mains supply has been restored to the pumping stations the previous checks should be repeated. When all vacuums are normal the beamline valves should be checked and reopened as necessary. Make sure that the vacuum is good on both sides before opening any valve.<br />
<br />
= Contact =<br />
* Lagy Baby mailto:lbaby@fsu.edu<br />
* Ingo Wiedenhoever mailto:iwiedenhoever@fsu.edu</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2012SF6 Gas Handling System2023-09-21T14:59:36Z<p>Iwiedenhoever: /* Shutoff Procedure */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas-handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem Vault pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
<br />
- Brian Schmidt, Senior Research Associate <br />
email bschmidt@fsu.edu, Tel. (850)644123 (work), (850) 4424338 (home) <br />
<br />
- Dr. Lagy T. Baby, Research Faculty III<br />
email lbaby@fsu.edu, Tel. (850)9800057 (cell)<br />
<br />
- Dr. I Wiedenhoever, Professor of Physics <br />
email iwiedenhoever@fsu.edu, Tel.(850)7285912 (cell)</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2011SF6 Gas Handling System2023-09-21T10:58:00Z<p>Iwiedenhoever: </p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas-handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
<br />
- Brian Schmidt, Senior Research Associate <br />
email bschmidt@fsu.edu, Tel. (850)644123 (work), (850) 4424338 (home) <br />
<br />
- Dr. Lagy T. Baby, Research Faculty III<br />
email lbaby@fsu.edu, Tel. (850)9800057 (cell)<br />
<br />
- Dr. I Wiedenhoever, Professor of Physics <br />
email iwiedenhoever@fsu.edu, Tel.(850)7285912 (cell)</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2010SF6 Gas Handling System2023-09-21T10:56:09Z<p>Iwiedenhoever: /* Contact */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
<br />
- Brian Schmidt, Senior Research Associate <br />
email bschmidt@fsu.edu, Tel. (850)644123 (work), (850) 4424338 (home) <br />
<br />
- Dr. Lagy T. Baby, Research Faculty III<br />
email lbaby@fsu.edu, Tel. (850)9800057 (cell)<br />
<br />
- Dr. I Wiedenhoever, Professor of Physics <br />
email iwiedenhoever@fsu.edu, Tel.(850)7285912 (cell)</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2009SF6 Gas Handling System2023-09-21T10:55:56Z<p>Iwiedenhoever: /* Contact */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
<br />
- Brian Schmidt, Senior Research Associate <br />
email bschmidt@fsu.edu, Tel. (850)644123 (work), (850) 4424338 (home) <br />
- Dr. Lagy T. Baby, Research Faculty III<br />
email lbaby@fsu.edu, Tel. (850)9800057 (cell)<br />
- Dr. I Wiedenhoever, Professor of Physics <br />
email iwiedenhoever@fsu.edu, Tel.(850)7285912 (cell)</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2008SF6 Gas Handling System2023-09-21T10:54:39Z<p>Iwiedenhoever: </p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2007SF6 Gas Handling System2023-09-21T10:53:53Z<p>Iwiedenhoever: </p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
All procedures around the Tandem accelerator gas handling system will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
= Worthington Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oil-less compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be set to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
These procedures will only be performed by qualified personnel: <br />
B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever. <br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2006SF6 Gas Handling System2023-09-21T10:17:00Z<p>Iwiedenhoever: /* Shutoff Procedure */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# In the Tandem Vault pit, close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2005SF6 Gas Handling System2023-09-21T10:15:21Z<p>Iwiedenhoever: /* Vacuum Pump Boosting for the Compressor */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# '''Entry into the Tandem pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder.''' <br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2004SF6 Gas Handling System2023-09-21T10:13:28Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
# Entry into the pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder. <br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the door ports are open, indicating that atmospheric pressure is reached, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank completely. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours before entering the tank. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2003SF6 Gas Handling System2023-09-21T10:10:55Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
# Entry into the pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder. <br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem door ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2002SF6 Gas Handling System2023-09-20T21:53:46Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
# Entry into the pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder. <br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the LE and HE tank doors on the front side of the tank. <br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2001SF6 Gas Handling System2023-09-20T21:45:34Z<p>Iwiedenhoever: /* Vacuum Pump Boosting for the Compressor */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
# Entry into the pit requires strict adherence to procedures for entry into controlled confined space. Fill out an Confined Space Entry Permit form available in the Tandem control room binder. <br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the two tank doors on the front.<br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=2000SF6 Gas Handling System2023-09-20T21:41:45Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the two tank doors on the front.<br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to "Confined Space" procedures, fill out a confined space entry permit available in the corresponding control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=1999SF6 Gas Handling System2023-09-20T21:37:02Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the two tank doors on the front.<br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to the "Confined Space" procedure specified in the corresponding <br />
Control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=1997SF6 Gas Handling System2023-09-20T20:17:20Z<p>Iwiedenhoever: </p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEEDS PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the two tank doors on the front.<br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to the "Enclosed Space" procedure specified in the corresponding <br />
Control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=SF6_Gas_Handling_System&diff=1996SF6 Gas Handling System2023-09-20T19:19:28Z<p>Iwiedenhoever: /* Venting the Tandem to Air */</p>
<hr />
<div>[[File:DiagramOfGasHandlingSystem.png|600px|thumb|right|Diagram of Gas-Handling System]]<br />
<br />
<span style="color:red">'''NEED PROOF READING</span><br />
<br />
= Worthington Compressor =<br />
<br />
The Worthington compressor was installed in the early ’70s. It is a two stage oiless compressor with teflon piston rings and metallic reed valve assemblies. In 1995 the Dresser Rand was the current spare parts supplier (tel.1-800-634-5565). The compressor model no. is 12 1/2 X 5 X 13 HB B-2 and the serial no. is L89186. The compressor is driven by a 125 HP 3-phase motor coupled by belt and pulley. The internal connecting rod and crank do require lubrication and the recommended lubricant is ISO-VG-150; AGMA Grade 4.<br />
<br />
The compressor is cooled with well water which is circulated through the water jacket surrounding the compressor cylinders and the heat exchanger. If the well water supply should fail the supply automatically changes over to the city water supply. The discharge from the compressor is sent to the dump well unless a valve change is made to route the water to the storm drain. The two labeled valves in the Gas Handling Room near the compressor need to be changed to allow the rerouting. After conditions return to normal and the well supply becomes available again, changes should be made to reroute the well water from dumping down the storm drain; the aforementioned valves will need to be put back in the original state. The switch from city water to well water supply is again automatic.<br />
<br />
= Emergency Valve Closures =<br />
<br />
If during a gas transfer the compressor should stop, a seal fail or some type of major leak of SF6start, it is important to safeguard the gas inventory. Also, at any time should a SF6 loss due to a failure on the Tandem pressure vessel or the storage tank and any of the directly attached valves occur a transfer of the SF6 inventory is suggested immediately. This, however, should not take precedent over safety as large quantities of SF6 can displace life sustaining air. Depending on where one is in the gas transfer the compressor may or may not be running; the response depends on whether the compressor is running.<br />
<br />
Below are the responses to three sets of circumstances that may confront the operator; some valves may or may not already be closed. The valves affected in the Gas Handling Rm. are shaded red in the preceding room layout (figure 5). After the crisis has passed and the transfer piping schematic (figure 11) is consulted a more sensible arrangement of valves may be preferred.<br />
<br />
== Compressor is Off: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| LE Tank Valve || Tandem Vault<br />
|-<br />
| HE Tank Valve || Tandem Vault<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
== Compressor Has Failed During Gas Transfer: No Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 40 || Gas Handling Rm., south wall<br />
|- <br />
| Valve 41 || Gas Handling Rm., south wall<br />
|}<br />
<br />
== Compressor Is On: Large Leak Detected ==<br />
<br />
{|class="wikitable"<br />
|'''Valve (close in order)'''||'''Location'''<br />
|-<br />
| Valves 5 & 6 || Gas handling room, orange piping, on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| Valve 20 || Gas handling room, yellow piping, exiting the surge tank<br />
|-<br />
| Turn the compressor off at the control panel || <br />
|-<br />
| Valve 2 || Gas handling room, orange piping on the W. floor between the back pressure regulator and compressor<br />
|-<br />
| LE Tank Valve || Tandem Vault, south end<br />
|-<br />
| Pump Pit Pneumatic Valve || Tandem Vault pump pit<br />
|-<br />
| HE Tank Valve || Tandem Vault, north end<br />
|-<br />
| Valve 45 || Outside atop the bottom white storage tank<br />
|}<br />
<br />
= Equalizing the SF6 Gas to the Outside Storage Vessel =<br />
[[File:EqualizingSF6toStorage.jpg|500px|thumb|right]]<br />
<br />
Time: ∼ 25 minutes. Change in Pressure: 80 to 50 lbs/in2.<br />
<br />
Ensure these valves are closed before beginning the gas transfer. Refer to the locator map (figure 5) for their approximate location: 38, 39, 43, 47, 35, 36, 4, 6, 13, 46, 40<br />
<br />
# In the Control Room, turn off the power to the Terminal Potential Stabilizer panel and withdraw the Corona Probe.<br />
# In the Tandem Vault, open the H.E. Tandem gas valve at the bottom of the North end of the tank. Ensure the tank lights are turned off.<br />
# Open the L.E. Tandem gas ball valve at the bottom of the tank South end.<br />
# Open valve 41, located at the south wall of the gas handling room, to allow the gas to equalize into the Storage Vessel.<br />
# Open valve 29 to collect the gas left in the piping from last gas transfer. The valve will probably be open already. If gas is not heard flowing it may be that valve 3, on the East side of the Tandem is closed, open it.<br />
# In the Control Room, remove the control power key and place it on top of the electronic rack.<br />
# Switch the Gas Pressure Alarm panel to the mute mode.<br />
# When gas is no longer heard flowing through the piping, go to the next step.<br />
<br />
<br />
= Compressing the SF6 to the Storage Vessel =<br />
<br />
[[File:CompressingSF6toStrage.png|500px|thumb|right]]<br />
<br />
Time: ∼ 90 minutes. Change in Pressure: 50 lbs/in2 to 23” Hg.<br />
<br />
# Close the two brass Hygrometer shutoff valves. One is behind the green panel at the H.E. beamline support and the other is on the H.E. Tandem end plate.<br />
# Close valve 41, south wall of Gas Handling Room, to route the gas from the Tandem through the compressor to the Storage Vessel.<br />
# Open valve 40 to allow the gas from the compressor to fill the Storage Vessel.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly, the back pressure regulator should ensure the input pressure to the compressor does not go positive. Should a failure occur and the input pressure become positive the compressor will shut down.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure ( < 3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressor throughput. Don’t allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by slightly<br />
# opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the Tandem’s pressure gauge at the H.E. end registers 23” Hg (approximately -10.8 psig on the Control Room SF6 parameter panel display). The ball valve to the right of the gauge may need to be opened. Proceed to the next section.<br />
<br />
= Vacuum Pump Boosting for the Compressor =<br />
<br />
# At the H.E. end of the Tandem, connect the Varian 501 gauge controller to the thermocouple. Next to the controller, reset the Rootes Blower run time meter to zero.<br />
# Close the H.E. Tandem gas valve.<br />
# In the Gas Handling Room (figure 5), close valves 4, 5 and 6.<br />
# Open valve 20 slightly and ensure the surge tank pressure begins to drop. The input to the compressor must remain less than atmospheric or the compressor will shut down.<br />
# The procedure for starting the vacuum pumps follows; they are located below the Tandem in the pit.<br />
## Ensure valve X2, a 1/2” ball valve between the Rootes blower and the Kinney, is closed.<br />
## Open valve X1, located on the pit wall in the Southwest corner, to vent the stagnant air left in the piping and Rootes Blower.<br />
## Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter. Allow the mechanical pump to run for 30 seconds then continue to the next step.<br />
## There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the bottom position, manual mode; the Rootes will come on. Allow it to run for 30 seconds and then slide the three position switch to the top, SF6 automatic mode. The Rootes will come on when the Varian 501 controller set point one is reached.<br />
## Wait for the blower shaft to slow and then close valve X1.<br />
## Open V10 which directs the discharge of the vacuum pumps to the compressor input.<br />
# Open the Tandem’s pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# In the Gas Handling Room, open valve 20 the rest of the way, yet maintain a pressure below 8” Hg at the 5 micron filter.<br />
# When the Tandem pressure reaches 4.6 torr, the set point, the thermocouple controller will automatically activate the Rootes blower. If the Tandem pressure is too high the Rootes will trip its circuit breaker and must be reset behind the control panel.<br />
# At ∼ 200 microns begin the shutoff procedure. The Control Room SF6 parameter panel display range of sensitivity will end at approximately -14.2 psig.<br />
<br />
<br />
= Shutoff Procedure =<br />
<br />
# Close the Tandem pneumatic valve in the vault pit. Use both the toggle switch and the key.<br />
# Turn off the Rootes Blower wall light switch and slide the 3-position switch to the manual mode, the bottom position. Allow the blower to slow.<br />
# Close V10 which isolates the input to the compressor.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# In the Gas Handling Room (figure 5), close V20 yellow piping.<br />
# Quickly close V2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# Close V40, south wall in the Gas Handling Room.<br />
# Disconnect the thermocouple controller from the gauge head at H.E. end of the Tandem.<br />
<br />
= Venting the Tandem to Air =<br />
<br />
Time: ∼ 30 minutes + 2 hours. Change in Pressure: 150 millitorr to 1 atmosphere.<br />
<br />
# Turn the Tandem ports to the open position. The vacuum will keep the ports sealed shut.<br />
# Partially open valve 43, red piping in gas handling room (figure 5). As the flow is heard slowing, open valve 43 more. Continue until completely open.<br />
# After the ports are open, close valve 43.<br />
# Open the two tank doors on the front.<br />
# Place the fan in the Tandem L.E. port and turn on so that air is pulled out through the L.E. port.<br />
# Leave the air circulation on for at least two hours. <br />
# Assess the air quality with a portable air quality monitor<br />
# Turn on tank lights. The Tandem is ready for floor boards and/or working inside.<br />
# Access to the Tandem tank requires strict adherence to the "Enclosed Space" procedure specified in the corresponding <br />
Control room binder.<br />
<br />
= Removing Air from the Tandem =<br />
<br />
Time: ∼ 14 hours (overnight). Change in Pressure: 1 atmosphere to 25 millitorr.<br />
<br />
# Remove all items brought into the Tandem, wipe the terminal off with alcohol and paper towels, remove the floor boards and sweep the bottom of the tank clean. Ensure no debris is left on the Tandem pneumatic valve flapper surface inside the tank; use the ShopVac vacuum cleaner. Turn the Tandem tank lights off.<br />
# Shut the Tandem port doors and turn them partially closed. It will be difficult to completely close them until a vacuum is established. Make an attempt to close them at 14” Hg; typically, the lower the vacuum reached the easier it is to turn close the port doors.<br />
# Ensure that valves 2 and 43 in the Gas Handling Room and 10 and 11 in the Tandem pump pit are closed (See figure 5).<br />
# Ensure that valve X2, a 1/2” ball valve between the Rootes blower and the Kinney pump, is closed.<br />
# Open valve X1 to allow pumped air to exit the building.<br />
# Start the mechanical pump by depressing the push button located on the panel to the left of the pumps. Hold the button down for at least 3 seconds to ensure the cooling water flow switch latches the pump run contacter.<br />
# There are two switches associated with the Rootes Blower. The upper most switch of the two is a wall type light switch that allows power to the second switch that is a three position switch. The wall light switch must be flipped up to enable the Rootes to come on. Slide the three position switch to the middle position, air automatic mode. The Rootes will come on when the Varian 501 controller set point two is reached.<br />
# Open the Tandem pneumatic valve by turning the key at the control panel and flipping the switch located near the valve on the flexible wire conduit.<br />
# Connect the Thermocouple controller to the gauge head at the H.E. end of the Tandem.<br />
# Allow the Tandem to be pumped on over night to remove absorbed gases and water vapor.<br />
# In the morning the Tandem vacuum should be at ∼ 25 millitorr. Close the pneumatic valve with the key and toggle switch. Turn off the Rootes Blower wall light switch and return the three position switch to the manual mode, slide to the<br />
# bottom position. Allow the blower to slow.<br />
# Close X1 which allows the pumps to exhaust outside the building.<br />
# Open the l/2” yellow ball valve labeled X2 between the Rootes blower and the Kinney pump.<br />
# Turn off the mechanical pump by depressing the stop button.<br />
# Close valve X2 when air no longer flows.<br />
# Check and top off if necessary the Rootes blower and Kinney pump oil.<br />
<br />
= Equalizing SF6 into the Tandem =<br />
<br />
Time: ∼ 60 min. Change in Pressure: 25 millitorr to 50 lbs/in2.<br />
<br />
# Close the ball valve before the +30 psi -30” Hg gauge at the H.E. end of the Tandem.<br />
# Disconnect the Thermocouple controller lead from the gauge head.<br />
# Ensure valve 41, in the Gas Handling Room (figure 5) behind the yellow paint cabinet, is closed.<br />
# Open valve 39, red piping to the left of the grey drier/desiccant tanks.<br />
# Open valve 40 (next to 41) partially, especially on cold mornings to prevent thermal shock to the accelerator column. As the flow rate is heard slowing, rotate the ball valve open more.<br />
<br />
= Compressing SF6 into the Tandem =<br />
<br />
[[File:CompressingSF6fromStorage.jpg|500px|thumb|right]]<br />
<br />
∼ 4 hours, 50 to 90 lbs/in2.<br />
<br />
# Close valve 40, south wall of Gas Handling Room (figure 5).<br />
# Open valve 41 to route the gas from the Storage Vessel though the compressor to the Tandem.<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when first starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valve 4 and then 5 slowly to ensure the input pressure to the compressor does not go positive; this will result in the shut down of the compressor.<br />
# SF6 is fed back into a shaft isolation chamber to prevent air creeping along the shaft into the gas inventory. A pressure gauge located on the compressor, West of the No.2 filter, should indicate a slightly positive pressure (<3 lbs/in2). Ensure this is the case.<br />
# After ∼ 30 minutes the back pressure regulator can be bypassed to increase the compressors throughput capacity. Do not allow the input to the compressor at the 5 micron filter to rise above 8” Hg or the heat exchanger between the two pumping stages to go over 45 lbs/in2 (top gauge on compressor). The bypass is allowed by<br />
# slightly opening valve 6 in steps to maintain the 8” Hg input pressure; eventually the valve will be completely opened.<br />
# Run the compressor until the input pressure at the 5 micron filter registers ∼ 27” Hg<br />
# Close valve 41.<br />
# Close valves 4, 5 and 6.<br />
# Stop the compressor and quickly close valve 2. Ensure the breaker is turned off after the valve is closed.<br />
# Close valve 39.<br />
# Close the L.E. Tandem gas valve.<br />
# Open the two brass Hygrometer shutoff valves. One is attached to the back of the green panel at the beamline support and the other to the H.E. Tandem end plate.<br />
# Turn the Gas Pressure Alarm panel back to “aural” in the Control Room. The gas transfer is complete.<br />
<br />
= Adding SF6 to the Inventory from Cylinder =<br />
<br />
SF6 is usually delivered in cylinders that come in two sizes: A and B. The cylinders are filled with liquid and their pressure will be the SF6 vapor pressure for the cylinder temperature. Due to the latent heat of vaporization, it will be necessary to add heat to the cylinder as the liquid changes to the gaseous phase and fills the Tandem. A typical pressure encountered would be ∼ 270 lbs/in2. At this vapor pressure the majority of the cylinder contents can be added directly to the tandem. When all the liquid has evaporated and the cylinder pressure matches the Tandem’s additional effort is necessary to empty the remaining cylinder contents. The last bit of gas can be sent to storage for recovery at the next gas transfer or the SF6 compressor can be used to add directly to the Tandem inventory.\<br />
<br />
= Adding SF6 directly to the Tandem From Cylinders =<br />
<br />
# Remove the cylinder caps and the plastic thread protector that often accompanies the valve. Attach the SF6 cylinders to the flexible lines at the fill manifold in the Gas Handling Room (figure 5); the cylinder threads are left handed. Attach the cylinder heaters to the bottom of the cylinders. If plastic mesh surrounds the bottle, roll it back on itself to ensure it does not melt.<br />
# Open the cylinder and fill line valves. Open the valve isolating the pressure gauge at the end of the fill manifold.<br />
# Close valve 45 located outside on top of the storage tank. Inside the Gas Handling Room ensure they’re closed or close valves 13, 2, 43, 47, 4 and 6. In the Tandem Vault ensure valve 3, on the East side of the Tandem, is closed.<br />
# In the Tandem Vault open the L.E. valve. In the gas handling room open valves 41, 40, 39, 29 and 46. The cylinders should now be emptying and will begin cooling down.<br />
# Turn on the heaters at the breaker panel around the corner from the fill station and leave them on until the cylinders either feel warm approximately 12” up from the heaters or SF6 no longer flows from the cylinders.<br />
# When the cylinders’ pressure has equalized with the tandem pressure, close valve 40. Continue to the next step to remove the remaining SF6.<br />
<br />
<br />
= Removing the SF6 remaining in the cylinders at Tandem pressure =<br />
<br />
These two procedures assume the valves are still in the state they were left in when adding the cylinder SF6 to the Tandem. Part A describes the procedure for transferring the residual cylinder gas with the compressor to the Tandem. Part B describes the procedure for transferring the residual cylinder gas to storage for addition to the gas inventory at the next gas transfer.<br />
<br />
=== Part A, to the Tandem: ===<br />
# Turn on the compressor breaker switch at south-east wall in the Gas Handling Room (figure 5) and ensure cooling water flows through the compressor at the flow gauges located at the north end of the compressor.<br />
# Quickly open valve 2, orange piping on the floor by the back pressure regulator, as soon as the compressor is started. Press the start button on the breaker panel; the compressor will make quite a bit of noise when just starting. The compressor will not start with a positive input pressure. The input pressure to the compressor is indicated by the pressure gauge at the No.2 five micron filter, painted orange and West of the yellow surge tank.<br />
# Open valves 4 and 5 while keeping the heat exchanger below 50 lb/in2. Valve 6, the regulator bypass, can be utilized yet keep the input to the compressor below atmospheric.<br />
# Pump on the cylinders until the compressor is at 28” Hg. Often there is a check valve installed on the cylinders that prevent a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied.<br />
# Quickly close valve 2 orange piping, after the compressor is turned off by depressing the push button. Turn the breaker to off after the valve is closed.<br />
# In the Tandem Vault close the L.E. valve and open valve 3. In the Gas Handling Room close valves 4,5, 6, 41, 39, 46, fill line valves, cylinder valves and gauge valve.<br />
# Open valve 45 on top of the outside storage tank.<br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders.<br />
<br />
=== Part B, To storage:===<br />
# In the Tandem Vault close the L.E. valve. In the gas handling room close valves 41 and 39.<br />
# Open valve 45 on top of the storage tank outside.<br />
# Back in the Gas Handling Room, open valve 41 to allow the SF6 to flow to the storage tank. Often there is a check valve installed on the cylinders that prevents a vacuum being drawn which may cause contamination of the cylinder, close valve 46 to check the cylinder pressure. Ensure the cylinders are left with little pressure by cycling valve 46 until satisfied with the cylinder residual.<br />
# After the cylinders are emptied close the individual cylinder and manifold valves. Close valve 41.<br />
# In the Tandem Vault open valve 3. <br />
# Return the empty cylinders to outside storage for return. Use the chains provided on the West side of the Gas Handling Room loading dock to secure the cylinders. A call to the supplier of the SF6 will hasten the cylinder collection.<br />
<br />
= SF6 Gas Drying =<br />
<br />
The three major components of the gas drying system are the blower, desiccant tanks and hygrometer. SF6 from the accelerator is removed at the L.E. valve passed through the dryer circuit and then returned through the H.E. valve via the blower. The desiccant beds will remove water from the gas as it is continuously cycled until a sufficiently low dew point or water vapor content is reached, ∼ 10 ppm. The desiccant in the tanks does, however, adsorb a finite amount of water and will require reactivating when it has become saturated. The desiccant is reactivated by passing hot air through the tank evaporating the water that was removed from the SF6.<br />
<br />
=== Reactivating the Gas Dryer ===<br />
# Ensure valves 35, 37 and 47 are closed.<br />
# Inspect the pressure gauges atop the silver/grey desiccant tanks. If they are pressurized slowly open valve X-3 to release the pressure.<br />
# After the tank pressure is released, open valve X-4 and turn on the power at the red electronics box to the north of the desiccant tanks. A blower should come on along with the heater elements; the red light atop the electronics box should be illuminated.<br />
# Allow the reactivation cycle to continue; it will automatically shut off when the desiccant tank temperature reaches the thermostat set point, ∼ 3 hours.<br />
# Close the two valves X -3 and -4, and turn off the switch at the electronics box. Allow the desiccant tanks to cool to room temperature before attempting to dry the SF6.<br />
<br />
=== Recirculating the Gas ===<br />
This procedure assumes the Tandem has been secured in the normal fashion after being gassed-up and the dryer has been reactivated.<br />
<br />
# Ensure valves 35 (blue piping Gas Handling Room, figure 5), 29 (red piping Gas Handling Room), 3 (orange piping east side of Tandem), X-3 and X-4 (gray piping gas handling room) are CLOSED.<br />
# Open valves 36, 37, 47 (blue piping gas handling room), the L.E. Tandem valve and H.E. Tandem valve.<br />
# The power switch for the blower used to recirculate the SF6 through the desiccant tanks is located at the fuse box to the left of the entrance to the Tandem Vault<br />
# L.E. end labeled Recirculator. Three push buttons are located at the bottom of box, also, a grey extension cord should be hanging from the bottom, plug the cord into one of the outlets immediately to the right. Depress the start button to turn on the blower in the blue tank in the north east corner of the Gas Handling Room.<br />
# Allow the gas to recirculate through the dryer circuit until the hygrometer indicates a dew point or water vapor concentration that is acceptable (below -50◦F)<br />
# Turn off the blower and close valves 36, 37, 47, the L.E. Tandem valve and H.E. Tandem valve.<br />
# Ensure that valves 3 and 29 are left open.<br />
<br />
<br />
= SF6 Leak Checking Gun =<br />
<br />
When ever a SF6 leak is suspected, or when making routine checks after gas transfers the SF6 leak detector or leak checking gun can be used to localize small, inaudible leaks as small as 0.2 cc/sec. Normally the gun is kept in the gray Tandem Cabinet in the NW corner of the control room. Detailed instructions concerning the gun are included in the black carrying case. A general description for setting the detector up follow and are included in the carrying case.<br />
<br />
# Ensure there is at least 150 lbs. of argon pressure in the cylinder. Open the cylinder valve to check this.<br />
# On the gun, turn the selector switch to the check volts position and squeeze the guns trigger; the meter should indicate between 60-80 divisions unless the batteries need replacing.<br />
# The Detector will require a purge period of five minutes or so. Press the check detector button while simultaneously squeezing the trigger; the meter should indicate 0 before the purge and 40 or more divisions afterwards. It does not some maintenance of the gun is in order.<br />
# Turn the selector switch to the appropriate sensitivity and adjust the zero. Normally I adjust it to zero while at the highest sensitivity in the Control Room. The zero setting will be altered some as the detector cell cleans up.<br />
# Check the pressure vessel for leaks by bringing the gun barrel or tip into close proximity to areas suspected of leaking SF6.<br />
# Ensure the cylinder is turned off before putting the leak checking gun in the carrying case and back into the gray cabinet.<br />
<br />
= Contact =<br />
* <span style="color:red">who should be contacted? </span></div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=1995Radiation Safety2023-09-20T19:09:45Z<p>Iwiedenhoever: /* Accelerated Ion Beam */</p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas. The operator in charge has to verify that no person remains in the area before the doors are closed and the door interlock <br />
alarms in the control room are activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below 2.5 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, all persons have to leave the affected areas and the operator in charge has to verify that no person remains in the areas before the doors are closed and the door interlock alarm in the control room is activated. The same rules as in 3.a apply in the case of access doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.5 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed, the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.5 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the beacon will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.5 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any month. This dose corresponds to spending 25 minutes, everyday, in a radiation field of 2.5 mREM/h.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=1994Radiation Safety2023-09-20T19:06:35Z<p>Iwiedenhoever: /* General Procedures and Access to Accelerator Areas */</p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas. The operator in charge has to verify that no person remains in the area before the doors are closed and the door interlock <br />
alarms in the control room are activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below 2.5 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, all persons have to leave the affected areas and the operator in charge has to verify that no person remains in the areas before the doors are closed and the door interlock alarm in the control room is activated. The same rules as in 3.a apply in the case of access doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.5 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed, the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.5 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the sign will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.5 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any month. This dose corresponds to spending 25 minutes, everyday, in a radiation field of 2.5 mREM/h.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=1993Radiation Safety2023-09-20T19:03:06Z<p>Iwiedenhoever: /* General Procedures and Access to Accelerator Areas */</p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas. The operator in charge has to verify that no person remains in the area before the doors have to be closed and the door interlock <br />
alarms in the Control room have to be activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below 2.5 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, all persons have to leave the affected areas and the operator in charge has to verify that no person remains in the areas, the doors to the areas will be closed and the door interlock alarm in the control room will be activated. The same rules as in 3.a apply in the case of doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.5 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed and the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.5 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the sign will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.5 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any month. This dose corresponds to spending 25 minutes, everyday, in a radiation field of 2.5 mREM/h.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=1990Radiation Safety2023-09-19T19:26:47Z<p>Iwiedenhoever: </p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. <br />
Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas, the doors have to be closed and the door interlock <br />
alarms in the Control room have to be activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the <br />
LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, <br />
the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below <br />
2.5 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, the doors to the areas will be closed and the door <br />
interlock alarm in the control room will be activated. The same rules as in 3.a apply in the case of doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2.5 mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed and the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the intent to inject beam into a new area through the laboratory intercom before injecting it. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.5 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the sign will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.5 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any month. This dose corresponds to spending 25 minutes, everyday, in a radiation field of 2.5 mREM/h.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Radiation_Safety&diff=1989Radiation Safety2023-09-19T19:23:40Z<p>Iwiedenhoever: </p>
<hr />
<div>== General Procedures and Access to Accelerator Areas ==<br />
Considerations of safety to personnel and minimization of risk to the accelerator have led to the following procedures, <br />
which will be adhered to at all times: <br />
<br />
1. When the accelerator is operating there will be a qualified operator and a second person in the Control Room, Computer Room Accelerator Room or <br />
Target Room at all times. The only exception is for a short period (not exceeding 20 minutes) when one of the two will be away from the accelerator area. <br />
During this period the remaining person will stay in the Control Room. There will be a person experienced in the "start up" and "shut down" of the source <br />
on duty at all times. <br />
<br />
2. Radiation dosimeters have to be worn every time a person enters the Tandem Hall, Linac Hall or Target Rooms, whether beam is present or not.<br />
<br />
3.a. For beams with Z<4 (H,He,Li): Access to the Tandem Hall, the Linac Hall or/and the Target Rooms is not allowed while a beam with Z<4 is present in the area. <br />
Before a beam with Z<4 is allowed into an area, all persons have to leave the respective areas, the doors have to be closed and the door interlock <br />
alarms in the Control room have to be activated. If a door is opened while the beam is present, the interlock system will automatically interrupt the beam at the <br />
LE end of the Tandem. The operator in charge will investigate the reason the doors were opened. Only after verifying that nobody is present in the protected area, <br />
the operator will close the affected door and re-activate the beam. <br />
<br />
3.b. For beams with Z>=4: Access to the Tandem Hall, the Linac Hall and/or the Target rooms is only allowed while the Gamma and Neutron dose rates in the area are below <br />
2.5 mrem/h. Before access is granted to a given area, the radiation levels will be verified at the installed area radiation monitors and with portable gamma and neutron radiation monitors, <br />
which are placed near the location where a person works. If radiation levels are above these limits, access to the areas is prohibited, the doors to the areas will be closed and the door <br />
interlock alarm in the control room will be activated. The same rules as in 3.a apply in the case of doors being opened. <br />
<br />
4. In all cases, the Tandem HE shield door should be closed if a beam is being accelerated, independent of the radiation levels. <br />
<br />
5. If the Tandem is being conditioned and/or levels of X-rays above 2mRem/h are observed on the Tandem Area x-ray monitor, the Tandem shield door has to be closed and the LE Shield door has to be locked and the door alarm has to be activated in the control room.<br />
<br />
6. Any time a beam delivery is initiated into the Tandem, the Linac Hall or the Target rooms, the operator will announce the presence of beam to that area through the laboratory intercom. <br />
<br />
More detailed procedures addressing specific areas of the laboratory are listed below.<br />
<br />
== Sources of Radiation around the Tandem == <br />
<br />
In the Tandem area the sources of radiation are the Tandem itself, the accelerated ion beam, activated material and the ion sources. In the target room there is the ion beam and the possibility of activated material.<br />
=== Ion Sources ===<br />
The high voltages involved with ion sources result in some x-rays during operation. For example, 2 mREM/h is typically measured near the injection magnet when the sputter source is operating at 120 kV (However, as with all high voltage equipment, a greater hazard by far is the possibility of electrocution).<br />
<br />
=== Tandem ===<br />
The terminal and acceleration tubes near the terminal can be a strong source of x-rays, depending on the operating conditions (terminal voltage, beam current, etc.). Radiation levels at the tank wall near the terminal of 100 mREM/h are not uncommon.<br />
During Conditioning and whenever the radiation doses exceed 2.5 mRem/h, the Tandem access doors have to be closed and secured through the interlock alarm panel in the control room.<br />
<br />
=== Accelerated Ion Beam ===<br />
The main factors on which the level of radiation resulting from the accelerated ion beam depend have been mentioned above. As regards to the Tandem, little nuclear radiation (as opposed to x-rays) is to be expected at the Low Energy end – except for proton, deuteron and 3He, 4He beams. Significant levels of γ-rays and neutrons are to be generally expected at the High Energy end of the Tandem. And at various places along the beam path into the target room and to the experimenters target. Again, in general, higher currents, higher energies and lighter projectiles all tend to produce more radiation. Usually the strongest sources will be the entrance and exit slits of the 90◦ magnet.<br />
<br />
'''Procedures'''<br />
# Do not use the route past the H.E. end of the Tandem to access the Linac hall when there is a beam from the Tandem. If beam is being run in the Linac area, use the route through the target room 1. If beam is being run in the Target room 1, enter and exit the Linac through the door in the hallway.<br />
# If radiation at the entrance to the H.E. end of the Tandem exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
# If radiation at the entrance to the Target Room 1 area exceeds 2.5 mREM/h, the radiation door will be closed to prevent access.<br />
<br />
== Sources of Ionizing Radiation In the Linac ==<br />
<br />
There are three distinct sources of radiation in the Linac area: the resonators, the accelerated ion beam, and any material (slits, etc.) which has been activated by bombardment with the ion beam.<br />
<br />
=== Resonators ===<br />
The superconducting resonators, which make up the Linac, produce x-rays when operating. The production of x-rays increases sharply with the R.F. field level at which the resonators are operating. For example, with a portable Geiger counter placed against the cryostat wall, the radiation from resonators running at 2 MV/m or less was found to be barely detectable (<0.04 mREM/h), while a resonator running at 2.25 MV/m gave 7 mREM/h measured against the cryostat wall. <br />
<br />
In the “shadow” of the blue radiation shields, x-ray radiation is currently barely detectable. However, this is not the case during resonator conditioning, nor will it be the case as operating field levels of 3 MV/m are approached.<br />
<br />
'''Procedure''': A series of Geiger counters have been placed under the cryostats to detect x-rays from the resonators. When the resonators are excited and emitting x-rays, these Geiger counters cause red lights mounted on top of the cryostats to illuminate.<br />
# Whenever these lights are on, the walkway beside the cryostats, the tunnel under the cryostats and the tops and ends of the cryostats are out of bounds. Anyone needing to work in these areas with the resonators excited should use a Geiger counter to monitor the radiation level first.<br />
# Whenever working in the shadow of the radiation shield, but near a resonator operating at “high field”, or being conditioned, use a Geiger counter to monitor the radiation level. If in doubt, use a Geiger counter.<br />
<br />
=== Sources of radiation due to the accelerated ion beam or activated parts are the same as those described for the experimental areas ===<br />
<br />
== Sources of Radiation in the Experimental Areas ==<br />
=== Accelerated Ion Beam ===<br />
One source of radiation is the accelerated ion beam, or rather, the nuclear reactions produced when the beam strikes various objects. The effective sources are therefore the various slits, apertures, beam stops, magnets boxes along the path of the beam, and finally the experimenters target chamber. Because large fractions of the ion beam are usually rejected at the entrance and exit slits of the 90◦ magnet, these are usually the strongest sources. The intensity of radiation from a small source (such as a set of slits) fall off with distance according to the “inverse square law” – often the radiation level measured against a set of slits may be quite high, but is negligible a few feet away.<br />
<br />
This beam-induced radiation consists mainly of fast neutrons and gamma-rays, and is properly detected with a neutron monitor and Geiger-counter respectively. Although often the radiation will be emitted roughly equally in all directions from the object being bombarded, in some cases the neutron radiation will be much stronger in the directions close to that of the ion beam, that is the neutrons are “forward peaked”. In general, because of their greater penetrating power, and because of their greater biological effectiveness, neutrons pose the greater hazard.<br />
<br />
The amount of radiation produced depends on the type of beam, the beam energy, the beam current and on the material being bombarded, and so obviously varies greatly from experiment to experiment. In general, however, one can expect the radiation to increases as the beam energy increases and as the mass of the ion decreases. For example, the first Linac run used a ∼20 nA 29Si beam at 95 MeV. Except near slits, the beam induced radiation was undetectable using the Geiger counter and neutron monitor. By contrast, a high-current 6Li or proton beam could produce levels of around 100 mREM/h.<br />
<br />
'''Procedures''': A beacon on the switching magnets in either Target-room 1 or Target-room 2 will flash whenever there is an ion beam in the experimental hall (the sign will come on when BS-1 or BS-2, respectively are open).<br />
# When a beam is being run in the Linac area, the doors to the hallway will be locked from the inside, independent of the radiation levels. All access will be through the control room and target room 1 and is to be controlled by the accelerator operator. <br />
# Once an experiment is running, a radiation survey will be carried out. If the radiation exceeds 2.5 mREM/h, access to the experimental area is prohibited, the access doors to the Tandem, Target Room 1 and the Linac Hall/Target Room 2 will be closed and the door interlock will be activated while the beam is delivered.<br />
<br />
=== Activated Material ===<br />
The third source of radiation is the radioactivity induced in material (slits, targets, etc.) that has been bombarded by an ion beam for a period of time. The radiation, mainly γ-rays and β-rays, can be detected with a Geiger counter. The amount of activity depends on the type, energy and currents of the bombarding beams, on the material being bombarded, and the length of time for which it was bombarded, and the length of time elapsed since bombardment.<br />
<br />
'''Procedure''': Use a Geiger counter before working on, or handling any device that has been bombarded by an accelerated ion beam. Be especially careful to contain any loose radioactive material. For proper disposal, contact Radiation Safety.<br />
<br />
== Source of Ionizing radiation from RESOLUT ==<br />
The operation of the RESOLUT radioactive-beam facility creates a combination of radiation sources, which are also present in other experiments and beam lines. Since it operates at higher beam intensity than most experiments, heightened precautions are advised. Radiation sources include X-rays from the superconducting resonator. Neutron and Gamma-radiation from the area of the production target, Neutron and Gamma-radiation from the area near the focal plane, where the primary beam is separated from the secondary beam products. Beam line parts may be activated during extended operation.<br />
<br />
== Radiation Doses and Dosimetry ==<br />
Radiation Dose: The statutory limit for “radiation workers” – anyone with a film badge, over 18, and not pregnant, is a dose of 1.25 REM per quarter. This is the dose you would receive if while you were at work, you were continuously exposed to a radiation level of 2.5 milliREM per hour throughout the 500 working hours of the quarter:<br />
<br />
2.5 mREM/h * 500 h = 1.25 REM<br />
<br />
However, there is no reason for anyone in the Tandem-Linac lab to receive even a small fraction of this dose. In fact, except under exceptional circumstances no one should need to receive a dose above the detection threshold of the film badge, namely 20 mRem (the rough equivalent of a chest x-ray) in any month. This dose corresponds to spending 25 minutes, everyday, in a radiation field of 2.5 mREM/h.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1988Ion Sources2023-09-19T19:17:20Z<p>Iwiedenhoever: </p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# Turn on the pre-accelerator high-Voltage supply <br />
# In the control room increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power supply cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rods extending out of the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Pre-accelerator high-Voltage supply". <br />
# '''Lockout the power plug using a lockout device available in the control room cabinet''', following the instructions for "SNICS Ion source lockout". and filling an entry in the lockout log book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the lockout-tagout book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator high-Voltage supply power cord and plug it in, noting the "unlocked" state in the "lockout tagout" log book located in the control room. <br />
# Turn the pre-accelerator high-Voltage supply on and push the green "High Voltage" button. <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lockout the power plug labeled "Pre-accelerator high-Voltage" using a lockout device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lockout tagout logbook. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''lockout devices''', and attach a '''tag''' to them. <br />
# Write a corresponding entry in the lockout tagout log book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# '''Remove the lockout device''' on the "Gap lens" power supplies and plug it into power outlets marked "Vacuum interlocked". <br />
# Remove the lockout tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the control-rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV with the control-rod from outside the cage. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages with their respective control-rods. <br />
# '''Remove the lockout device''' on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1987Ion Sources2023-09-19T19:10:36Z<p>Iwiedenhoever: </p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# Turn on the pre-accelerator high-Voltage supply <br />
# In the control room increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power supply cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rods extending out of the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Pre-accelerator high-Voltage supply". <br />
# '''Lockout the power plug using a lockout device available in the control room cabinet''', following the instructions for "SNICS Ion source lockout". and filling an entry in the lockout log book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the lockout-tagout book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator high-Voltage supply power cord and plug it in, noting the "unlocked" state in the "lockout tagout" log book located in the control room. <br />
# Turn the pre-accelerator high-Voltage supply on and push the green "High Voltage" button. <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lockout the power plug labeled "Pre-accelerator high-Voltage" using a lockout device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lockout tagout logbook. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''lockout devices''', and attach a '''tag''' to them. <br />
# Write a corresponding entry in the lockout tagout log book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# Remove the lockout devices on the "Gap lens" and "Probe" power supplies and plug them into power outlets marked "Vacuum interlocked". <br />
# Remove the lockout tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages.<br />
# Remove the lockout device on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1986Ion Sources2023-09-19T19:04:39Z<p>Iwiedenhoever: </p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# Turn on the pre-accelerator high-Voltage supply <br />
# In the control room increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rod extending from the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Pre-accelerator high-Voltage supply". <br />
# '''Lock-out the power plug using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out". and filling an entry in the lock-out-tag-out book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the log-out-tag-out book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator high-Voltage supply power cord and plug it in, noting the "unlocked" state in the "log-out Tag-out" log located in the control room. <br />
# Turn the pre-accelerator high-Voltage supply on and push the green "High Voltage" button. <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lock-out the power plug labeled "Pre-accelerator high-Voltage" using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lock-out-tag-out book. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''Lock-out devices''', and attach a '''Tag''' to them. <br />
# Write a corresponding entry in the lock-out-tag-out book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# Remove the Lock-out devices on the "Gap lens" and "Probe" power supplies and plug them into power outlets marked "Vacuum interlocked". <br />
# Remove the Lock-out tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages.<br />
# Remove the Lock-out device on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1985Ion Sources2023-09-19T19:02:54Z<p>Iwiedenhoever: </p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# Turn on the pre-accelerator high-Voltage supply <br />
# In the control room increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rod extending from the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Preaccelerator Power Supply". <br />
# '''Lock-out the power plug using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out". and filling an entry in the lock-out-tag-out book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the log-out-tag-out book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator power supply module power cord and plug it in, noting the "unlocked" state in the "log-out Tag-out" log located in the control room. <br />
# Turn the pre-accelerator power supply on and push the green "High Voltage button". <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lock-out the power plug labeled "Pre-accelerator high-Voltage" using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lock-out-tag-out book. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''Lock-out devices''', and attach a '''Tag''' to them. <br />
# Write a corresponding entry in the lock-out-tag-out book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# Remove the Lock-out devices on the "Gap lens" and "Probe" power supplies and plug them into power outlets marked "Vacuum interlocked". <br />
# Remove the Lock-out tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages.<br />
# Remove the Lock-out device on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1984Ion Sources2023-09-19T19:00:41Z<p>Iwiedenhoever: </p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from one state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the pre-accelerator high voltage supply to zero Volts. <br />
# In the Tandem vault, close the source exit valve and switch the pre-accelerator high-Voltage supply off.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# In the control room, turn on the pre-accelerator power supply and increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rod extending from the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Pre-accelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the pre-accelerator power supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Preaccelerator Power Supply". <br />
# '''Lock-out the power plug using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out". and filling an entry in the lock-out-tag-out book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the log-out-tag-out book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and pre-accelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator power supply module power cord and plug it in, noting the "unlocked" state in the "log-out Tag-out" log located in the control room. <br />
# Turn the pre-accelerator power supply on and push the green "High Voltage button". <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the pre-accelerator high-Voltage supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lock-out the power plug labeled "Pre-accelerator high-Voltage" using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lock-out-tag-out book. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''Lock-out devices''', and attach a '''Tag''' to them. <br />
# Write a corresponding entry in the lock-out-tag-out book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# Remove the Lock-out devices on the "Gap lens" and "Probe" power supplies and plug them into power outlets marked "Vacuum interlocked". <br />
# Remove the Lock-out tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages.<br />
# Remove the Lock-out device on the pre-accelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the pre-accelerator HV supply on and raise the pre-accelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoeverhttps://fsunuc.physics.fsu.edu/wiki/index.php?title=Ion_Sources&diff=1983Ion Sources2023-09-19T16:17:59Z<p>Iwiedenhoever: /* Sputter Source */</p>
<hr />
<div>= General =<br />
'''WARNING - The ion sources of the accelerator laboratory will be at extremely high voltages during operation, up to 120000 V. <br />
<br />
Touching this equipment causes life-threatening electrical shocks''' <br />
<br />
All parts of the equipment at high Voltage are enclosed by grounded metal cages for the protection of laboratory users. <br />
<br />
Three cages are present: 1) The cage surrounding the SNICS ion source body <br />
2) the SNICS power supply cage 3) The cage surrounding the helium ion source and the new tritium ion source. <br />
<br />
'''Under no circumstance is personnel allowed to reach into the cage or use tools to attempt manipulating equipment inside the cages. Danger to your LIFE !'''<br />
<br />
Any components that require user adjustment during operation are controlled through permanently installed isolating plastic rods, which can be adjusted <br />
from outside the cage. <br />
<br />
Only qualified personnel B. Schmidt, Dr. L.Baby or Dr. I. Wiedenhoever are allowed to secure the High-voltage ion source areas using the <br />
Lockout procedures described below.<br />
<br />
Always follow the operating procedures described below.<br />
<br />
= Sputter Source =<br />
[[File:SNIC operation.png|300px|thumb|right|Sputter source Operation schematic]]<br />
[[File:SNICS ionSourceVolatge.png|300px|thumb|Sputter source Volatge Schematic]]<br />
<br />
The Sputter Source is used for most beams at the FSU accelerator. It is also identified by its brand name "SNICS".<br />
<br />
== Theory of Operation ==<br />
The '''S'''ource of '''N'''egative '''I'''ons by '''C'''esium '''S'''puttering (SNICS) produces a negative ion beam. A reservoir of cesium metal is heated so that cesium vapor is formed. This cesium vapor comes from the cesium oven into an enclosed area between the cooled cathode and the heated ionizing surface. Some cesium condenses onto the cool surface of the cathode and some of the cesium is ionized by the hot surface. The positively charged ionized cesium accelerates towards the cathode, sputtering material from the cathode at impact. Some materials will preferentially sputter neutral or positive particles which pick up electrons as they pass through the condensed cesium layer on the surface of the cathode, producing the negatively charged beam.<br />
<br />
== Ion source operation states ==<br />
The ion source and pre-accelerator can be in put into different states, depending on the phases of operation. The following procedures will make reference to transitions from on state to another. A) "Secured, Cold" state: All power sources are removed and locked-out. B) "Cold Idle" state: All power sources are turned off, but can be re-applied, the source and power supply cages stay closed. C) "Warm Idle" state: The power sources to the source remain on, but the "ionizer current" is turned down to preserve the source material fur further use. D) "Beam" state: producing ion beam to be injected into the tandem accelerator. <br />
<br />
'''The source needs to be in the "Secured, Cold" state before any access to the ion source cage or the power supply cage is made.''' <br />
<br />
Only qualified personnel Brian Schmidt, Dr. Lagy Baby and Dr. I. Wiedenhoever place the ion source into "Secured, Cold" state or to return it to beam operation from this state.<br />
<br />
== Temporary Turn Down: Bringing the source from "Operation" to "Warm Idle" state ==<br />
Qualified Personnel: All trained accelerator operators <br />
<br />
When a break or interruption in the experiment occurs and the negative ion source will not be required for four or more hours, it is desirable to turn down the source to prolong its operational life time.<br />
# In the control room, turn the preaccelerator high voltage supply to zero Volts and switch the power supply off. <br />
# In the Tandem vault, close the source exit valve.<br />
# Reduce the Cesium Boiler Heater to 35 on the variac scale by turning the control rod located at the high voltage cage.<br />
# Reduce the ionizer heater current by turning the control rod attached to the ionizer power supply located at the SNICS power supply cage. Reduce the current in four-Ampere steps separated by two minute intervals to fifteen Amperes. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Warm Idle" mode.<br />
<br />
== Bringing the source up from "Warm Idle" to "Beam" state==<br />
Qualified Personnel: All trained accelerator operators<br />
# Insert the LE Faraday cup and select the LE cup current on the beam integrator. <br />
# In the Tandem Vault, open the source exit valve after verifying the source vacuum status.<br />
# Verify that the source cage is closed and that the source is ready to start beam production <br />
# In the control room, turn on the preaccelerator power supply and increase the Voltage to the value required for the beam, which is typically 120 kV. <br />
# Increase the Ionizer heater current in four-Ampere steps, separated by two-minute intervals while observing the beam current measured on the LE CUP <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was reactivated and make not of the beam currents.<br />
<br />
== Turning the Source Down from "Warm Idle" to "Cold Idle" state ==<br />
Qualified Personnel: All trained accelerator operators<br />
<br />
When the use of the negative ion source is no longer required by the experiment, it is desirable to leave the source in a state to prolong the source life time. <br />
# Apply all steps listed for the Temporary Turn-Down above. <br />
# In the control room, turn the source deflectors down and off.<br />
# Turn the inflector magnet supply completely down.<br />
# At the SNICS power cage, turn the Lens, Extractor and Cathode H.V. supplies to zero with the control rod extending from the H.V. cage.<br />
# Reduce the einzel lens voltage to zero by depressing the labeled rocker switch at the H.V. cage control panel. <br />
# Note in the Tandem Log Book, located in the Control Room, the time the source was turned down to the "Cold Idle" mode.<br />
<br />
== Bringing the Preaccelerator and SNICS Source to "Secured, Cold" state. ==<br />
This procedure will only be performed by Brian Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# Reaching this state is required '''before any access''' to the SNICS Source cage or the SNICS Power Supply cage, for service or repair. <br />
# Bring the source to "Cold Idle" Mode, following the steps described above.<br />
# In the Tandem vault, switch off the preaccelerator power supply, which is located in a rack below the RF Buncher assembly and unplug the power cord labeled "Preaccelerator Power Supply". <br />
# '''Lock-out the power plug using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out". and filling an entry in the lock-out-tag-out book. <br />
# In the SNICS source power cage, verify that the Extraction, Cathode and Lens High-Voltage supplies read "zero" Volts. <br />
# Turn the key switch at the panel to turn off the isolation transformer providing platform power to the H.V. cage. '''Remove the key from the control panel''' and place it in the lock box next to the panel. '''Lock the box''' and '''apply a tagout form'''. Make an entry into the log-out-tag-out book. <br />
# Open the cage door in front of the SNICS source. <br />
# A shorting rod is provided, which is attached by cable to the cage door. Hold the shorting rod by its insulated handle, with the tip of the rod touch the source on each side of the endmost ceramic insulator. Repeat touching the parts of the source multiple times, verify that no sparking to the tip occurs, establishing that all parts are at ground potential. <br />
# Hang the shorting rod on the source body, between the air lock VAT valve and the HPS vacuum fitting clamp.<br />
# The source and preaccelerator are now in "Secured Cold" state, Access to the external source body and the power supply enclosure is now possible.<br />
<br />
== Bringing the source up from "Cold Secured" state to "Beam" state ==<br />
These instructions assume the correct cathode is installed and the Ion source vacuum is correct and sufficient to connect to the accelerator<br />
<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
# At the Ion source: Remove the grounding rod from the Ion source and hang it from the cage door in front of the SNICS source<br />
# Close the cage doors in front of the SNICS source.<br />
# Verify that the power supply cage is closed. <br />
# ''' Unlock the lock-box''' next to the Power supply panel. Obtain the panel-key, insert it into the Power supply front panel and turn it to "on". <br />
# If no source-operation parameters have been recorded or cannot be found set the SNICS Cathode and Extractor supplies to 7.5 KV.<br />
# Open the source exit valve <br />
# '''Remove the lock''' on the pre-accelerator power supply module power cord and plug it in, noting the "unlocked" state in the "log-out Tag-out" log located in the control room. <br />
# Turn the pre-accelerator power supply on and push the green "High Voltage button". <br />
# In the Control room: Turn on the pre-accelerator panel and raise the pre-accelerator to the desired Voltage, typically 120 kV. <br />
# Insert the L.E. faraday cup and depress the corresponding push button on the integrator panel. Select the most sensitive scale on the integrator initially and then adjust the scale if and when the beam current pegs the meter.<br />
# Turn the ion source deflectors to zero.<br />
# Adjust the inflector magnet supply to indicate the predicted setting for the negative ion that is to be injected into the Tandem. A table is provided on the inflector control panel.<br />
# If the beam has been run before and the source parameters are known, adjust the SNICS Cathode and Extractor supplies to those values at the High Voltage Cage out in the Tandem Vault. If the Ionizer heater is to be adjusted, do it in 4 ampere steps separated by 4 minutes intervals.<br />
# Beam should now be present on the L.E. cup; if not, adjust the inflector magnet slightly and attempt to find and maximize beam current. The inflector magnet should not be more than 0.15 units off of the predicted setting.<br />
# An iterative approach is used to maximize beam on the L.E. cup. After the magnet is fine tuned, adjust the SNICS Cathode and Extractor supplies in the Tandem Vault to maximize beam current. When satisfied, again adjust the inflector magnet in the Control Room and then the source H.V. supplies again. After this second round of tuning use the source deflectors in the Control Room to increase beam current on the L.E. cup. More rounds of adjustments should be attempted; however, maximum beam transmission through the Tandem does not occur at the same settings as those for maximum L.E. faraday cup beam current. Mostly the source deflectors and the inflector magnet require slight readjustment when tuning through the Tandem.<br />
# Assuming all the focusing and deflector elements are maximized for beam current, one can only adjust the Ionizer heater and the boiler temperature to attain more beam form the source. First, increase the Ionizer one ampere steps until the desired current is reached. The beam is ready for injection.<br />
Should one not have success with tuning the desired beam, reducing the ion source deflectors to 50% of the optimum for a couple of iterations of source voltages and inflector magnet adjustments might be a useful approach. Ultimately, the deflectors should be adjusted to give the maximum beam on target.<br />
<br />
== Cathode Change Instructions ==<br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever<br />
<br />
Bring the source to the "Cold Secured" State, locking out the High-Voltage potentials and power to the source. <br />
<br />
# At the source vacuum control panel are two toggle switches that must be placed in the “unprot” position; this is to prevent the isolation transformer from shutting off supplies due to a vacuum excursion in the source. Note the current vacuum indication at the backing line thermocouple controller on the source vacuum panel. Depress the red push button next to the baffle switch while making the change.<br />
# Open the source H.V. cage. <br />
# Hang the shorting rod between the air lock VAT valve and the HPS vacuum fitting clamp. <br />
# Remove the H.V. cathode lead from the stop clamp (aluminum bar) attached to the cathode stainless steel coolant tube.<br />
# Ensure the compression fitting sealing the cathode assembly is only finger tight and then withdraw the assembly slowly and carefully. At 5 3/4” of travel a scribed line on the stainless steel tubing will emerge from the compression fitting. At 1/4” later a second scribed line will emerge indicating that clearance has been afforded the VAT air lock valve and it can be closed. To close the valve rotate the black handle clockwise (up and to the right) until it comes to a stop.<br />
# The green knob on the Nupro valve can now be opened to let the cathode air lock region up to atmospheric pressure.<br />
# Use one hand to withdraw the probe assembly (cooling lines still attached) until it is free from the source. With a glove on the other hand remove (unscrew) the old cathode and replace it with the new one.<br />
# Install the cathode assembly back into the compression fitting; loosen the fitting if necessary to get the probe started and then tighten it finger tight again. Slide the assembly in until the first scribed line is even with the compression fitting.<br />
# A nylon roughing line with a stainless steel tube fitted to its end should be at the source bottom cage grating, ensure its free of debris and insert it into the Nupro valves compression fitting. Snug the fitting on the tube and ensure the valve is still open.<br />
# At the source vacuum control panel, shut the backing valve by putting its toggle switch in the manual close position.<br />
# On the backing line of the source diffusion pump is a right-angle, 1/4” brass valve with a black toggle handle, open this valve to allow the cathode air lock region to be pumped out with the roughing pump. The vacuum can be monitored at the backing line thermocouple controller on the source vacuum panel. When the vacuum has reached the reading previously noted (about 10 microns) close the green handled Nupro valve and then the brass valve on the backing line.<br />
# Vacuum permitting, open the backing line valve with the toggle switch at the source vacuum control panel and place the two toggle switches in step 4 back to the “prot” position. Depress the red push button next to the baffle switch while making the change.<br />
# Remove the nylon roughing line from the Nupro valve and place it back at the bottom cage grating.<br />
# While watching the sputter source penning gauge, open the VAT air lock valve by rotating the black handle counter clockwise (up and to the left) until it comes to a stop. A temporary degradation of the vacuum should be indicated by the penning gauge. If the vacuum does not show signs of recovering in 10 seconds close the air lock valve and determine the source of the gas load. Outgassing of the cathode is not uncommon and is indicated by a vacuum that quickly recovers but not to the level previous to the air lock valve being opened. The vacuum will slowly improve and attain the expected base vacuum of about 1 x 10−7 torr.)<br />
# Carefully slide the cathode assembly into the source until the aluminum stop clamp on the assembly is flush with the compression fitting. There may be an premature stop encountered before the stop clamp is flush with the compression fitting, if so, slightly wiggle the cathode assembly until it is free to be fully installed. Ensure the compression fitting is snug when the installation is complete.<br />
# Reconnect the clear lead for the cathode H.V. supply back to the stop clamp.<br />
<br />
# The cathode change is now completed. <br />
# Bring the source back to operation after the source vacuum has recovered to ∼1 x 10−6 torr. The inflector magnet and source supplies can now be tuned for the desired ion and beam current on the L.E. cup.<br />
<br />
== Description of Typical Cathode Behavior ==<br />
Most often the material packed into the SNICS cathodes is either a solid or powder. In general, new, unused cathodes are often found to require more time to reach the output level of cathodes that have seen previous use. The nature of the material and how it was stored, particularly if it is a hygroscopic or deliquescent, is of paramount importance to provide reliable negative ion output. Most powdered cathodes are pressed here in the lab and are inherently ''gassy'' due to voids in the pressed material. The solid material cathodes are the preferred cathode whenever possible. To reduce ''damage'' to the cathodes while they are not in use, it is imperative that the cathodes be wrapped tightly in aluminum foil and placed in a tightly capped bottle that has been back filled with argon.<br />
<br />
Solid cathodes when initially inserted into the source, will out-gas in a very short period of time. Beam from the ion source can typically be had in sufficient quantity in a few minutes.<br />
<br />
Powder cathodes work best when they are pressed with dry powder and stored in a dry environment. These cathodes will take longer to outgas than their solid counterparts and the ion source extractor and cathode voltages will often suffer stability problems. Previously used cathodes, especially depending on the nature of the material, can sometimes take up to half a day to behave in a stable fashion and produce the desired beam current.<br />
<br />
== Outgassing a New Ionizer ==<br />
<span style="color:#FF0000">'''DO NOT RUN THE IONIZER OVER 290 WATTS'''</span><br />
This procedure will only be performed by the qualified personnel B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever <br />
<br />
# Since the source has just been rebuilt it will need to be pumped on for at least three hours. After this time the vacuum should be in the low 10−6 torr range if there is no leak. Note in the logbook the source vacuum indication previous to outgassing the ionizer filament. If the vacuum has not reached this level in five hours a leak may be present and it will have to be corrected prior to heating the ion source filament.<br />
# The ionizer is typically left with a small current flowing through the ionizer after the rebuild just to ensure continuity. Assuming the vacuum has recovered, increase the ionizer current in three ampere steps every thirty minutes. If the vacuum has degraded to over 5 x 10−6 torr due to a previous current increase, hold off on subsequent increases. When the vacuum has returned to 5 x 10−6 torr or less begin the three ampere increases again.<br />
# When the Ionizer filament power is up to 290 watts for 30 minutes and the vacuum has improved to better than 5 x 10−6, begin looking for beam on the L.E. cup. Go to Sec. 7 for instructions for tuning beam out of the source. Instabilities in the Cathode and Extractor high voltage elements will cause the beam current to be erratic and can be an indication of poor vacuum in the ionizer region. The voltage instability also appears on the high voltage supply meter indications in the source high voltage cage. Patience or a reduction in the filament power level, if beam current requirements allow, should correct this problem. Regardless, reduce the ionizer temperature if possible to prolong its operational lifetime.<br />
<br />
= RF Ion Source =<br />
[[File:RFSourceOperation.png|400px|thumb|right|RF Source Operation Schematic]]<br />
<br />
== Theory of Operation ==<br />
The RF Ion source is almost exclusively used to produce negatively-charged helium beam. <br />
Helium is admitted into a quartz tube at a few millitorr, where it is ionized to He+ in an RF discharge. The ions are extracted through a tantalum exit canal by applying a 6 kV positive bias to the probe at the other end of the tube. Most of the probe-bias potential is dropped across a small region near the exit canal and the field lines have the effect of focusing and accelerating the ions through the canal. The ions emerge with an energy close to the probe potential. A large coil around the quartz tube produces a magnetic field which improves the coupling of RF power into the discharge. The He+ ion beam from the exit canal then passes through the Rubidium vapor charge-exchange cell. About 1% of the He+ entering the REC should get converted to He− in the 1s2s2p 4P5 2 metastable state. The negative ion lifetime of approximately 0.5ms is sufficient to reach the Tandem terminal stripper foil. The He- ions are then focused by passing through a gap lens with a potential difference of 7kv. The emerging beam is injected into a pre-accelerator tube.<br />
<br />
== Ion source operation states ==<br />
The Helium ion-source has three operation states: "A) Cold, secured": All power sources are removed from the source and locked-out. This state is required for repair or service inside the source body. "B) Warm, secured": All high-voltage potentials are removed from the source, but the RF-power remains active, providing plasma-activation. "C) Beam": All power sources are applied and beam is delivered. <br />
<br />
== Bring the source from "Beam" to "Cold Secured State" or "Warm Secured State" ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
# In the Tandem vault, switch off the preaccelerator power supply, which is located in a rack below the RF Buncher assembly and unplug the power cord. <br />
# '''Lock-out the power plug labeled "Preaccelerator Power" using a lock-out device available in the control room cabinet''', following the instructions for "Ion source lock-out" and filling an entry in the lock-out-tag-out book. <br />
# At the back-end on the outside of the source cage, turn the "Gap Lens" power supply to "zero" and the "Probe Power Supply" to zero. <br />
# Open the back-cage door. A grounding-hook connected to a grounded cable is provided. <br />
# Touch the top platform, the aluminum plate below the "Probe Power Supply", then touch the lower platform below the isolator posts to '''discharge the electrostatic energy'''.<br />
# Repeat touching these two platforms with the grounding hook several times to '''verify''' that no sparks occur when touching the platforms. <br />
# Hang the hook on the corner of the upper platform. <br />
# Switch off the "Gap Lens" and "Probe" Power Supplies.<br />
# Unplug the power "Gap Lens" and "Probe" Power Supplies and secure the with '''Lock-out devices''', and attach a '''Tag''' to them. <br />
# Write a corresponding entry in the lock-out-tag-out book. <br />
# If the source is to be brought into the "Cold Secured State", remove the RF power.<br />
<br />
== Bringing the Helium Source from "Cold, Secured" to the "Beam" state ==<br />
This procedure will only be performed by B. Schmidt, Dr. L. Baby or Dr. I. Wiedenhoever.<br />
<br />
[[File:RFSourceEinzelLensSchematic.png|500px|thumb|right|RF-Source Einzel Lens Schematic]]<br />
# Remove the Lock-out devices on the "Gap lens" and "Probe" power supplies and plug them into power outlets marked "Vacuum interlocked". <br />
# Remove the Lock-out tag and return it to the Control room, closing the entry in the log book. <br />
# Set the "Gap Lens" HV supply to positive polarity, leaving it switched off for now. <br />
# Insert the cup and switch it to "positive polarity" <br />
# Turn on the "Probe" power supply, leaving it turned to zero for now. <br />
# Turn on the RF supply power and set the probe magnet to 3-3.5 Amps. <br />
# Open the valve on the helium bottle. Open the helium leak valve until the discharge starts. Close it until the discharge is no longer pink and has become blue. The Penning gauge should only read a few 10−6 torr.<br />
# Remove the grounding-hook from the top platform and secure it at the cage wall, leaving the grounding-hook on the lower platform in place. <br />
# Close the cage doors and turn the Gap Lens supply "on" with the rod from the outside of the cage, raise the Voltage to ~5 kV. <br />
# Using the isolation rod from outside the cage, turn the "Probe" high voltage and set to +5 kV.<br />
# Optimize the positive beam current by varying the gas pressure and the probe magnet settings. <br />
# Once the beam is found to be sufficient (several micro-Amps), turn the Gap-Lens Power supply to zero. <br />
# Open the cage doors and place the grounding hook on the top platform, to verify that electrostatic energy is discharged. <br />
# Set the Oven Heater to ~48 Volts. The Chamber Temperature should rise, approaching ~55 Degrees C after ~20 minutes.<br />
# Switch the Gap-Lens power supply to negative polarity. <br />
# Switch the cup current polarity to "negative". <br />
# Close the cage doors and switch the Gap Lens supply "on" with the rod from the outside of the cage. <br />
# Raise the Gap-lens voltage to -5 kV. <br />
# There should be a negative current reading on the cup. Optimize the beam using helium pressure, probe magnet and probe voltages.<br />
# Remove the Lock-out device on the preaccelerator high-voltage supply power plug remove the corresponding tag and return it to the Control room, closing the entry in the log book. <br />
# Turn the preaccelerator HV supply on and raise the preaccelerator voltage to 80kV.<br />
# Optimize the beam current in the accelerator LE cup using the 3-degree magnet current and the Ion source.<br />
<br />
== RF Discharge Contaminants ==<br />
<br />
Oxygen and other species form negative ions with efficiencies much higher than helium. The admitted helium and desorbed gases from the RF source bottle and boron nitride exit canal insulator can be sources of contaminant beams. For optimum performance it is essential that the RF source bottle assembly be leak tight, that the helium used be greater than 99.99% pure, and that all He tubing and fittings be clean. In addition, it is also important to operate the RF discharge with the helium flowing for 1 or more days prior to the accelerator beam time to allow some of the contaminants to dissipate.</div>Iwiedenhoever