Image of Clarion2, photo by Tim.

Introduction

Clarion2 ^[1] is the successor of Clarion ^[2] (CLover Array for Radioactive ION beam). It is a 4π gamma ray detectors array with 16 High-Purity Germanium (HPGe) clover detectors. Each HPGe detector is shied with a BGO (Bismuth Germanate [Bi4Ge3O12]) shield.

Each clover detector has 4 crystals, color-coded as Red, Blue, Green, and Black. Here is the angular map for all 16 clovers. Further details of the array can be found here or here.

Clarion2 angular map. The purple dot is the center of each clover.

Notice :

Solid work model needed

HPGe Clover Detector

The detectors are produced by EURISYS Measure, now CANBERRA, owned by MIRION Technologies [1]. An approximate 3.3 kg clover detector consists of 4 coaxial crystals (dimension 50 mm in diameter, 80 mm in length) [Mirion webpage].

Typical photon-peak efficiency curve

CLARION2 efficiency curve by Tim Gray. The data points are from experimental measurments.

The absolute photo-peak efficiency at 1332 keV is ~1.8%.

The equation for the absolute efficiency curve is

$\epsilon (e_{\gamma }{\text{[keV]}})=\epsilon _{0}\exp ^{\left(\left(A+Bx+Cx^{2}\right)^{-G}+\left(D+Ey+Fy^{2}\right)^{-G}\right)^{-1/G}},$

$x=\ln \left({\frac {e_{\gamma }}{100}}\right),y=\ln \left({\frac {e_{\gamma }}{1000}}\right)$

$\epsilon _{0}=0.0037679$

$A=13.6858$

$B=1.4055$

$C=0.000$

$D=3.8942$

$E=-2.4073$

$F=0.0629$

$G=0.5000$

GEANT4 simulation

The performance of a single clover detector was simulated using GEANT4. The source code can be downloaded from https://github.com/goluckyryan/HPGeClover.

GEANT4 simulation of 152Eu

A GEANT4 simulation for Clarion2 can be found at https://fsunuc.physics.fsu.edu/git/pderosa888/CLARION2_GEANT4.

Clarion2 GEANT4 model

Trinity

Front view of TRINITY, photo by Vandana.

Trinity is formed by GAGG (Gadolinium Aluminium Gallium Garnet) scintillator crystals. It is located in the target chamber of the Clarion2. The GAGG crystals are arranged in 5 rings, covering 7-54 degrees. Currently only two rings are implemented, which cover 14-24 and 34-44 degrees respectively.

A single GAGG detector

Neutron Shield

In 2022 April, a set of neutron shields surrounded Clarion2 for shielding slow neutrons.

Clarion2 private network

The Clarion2 uses its own private network. The network structure is illustrated as following:

Fox's Lab network --- clarion2(Mac, gateway) ---- 10 Gb switch
                                                      +--------- clarion2 DAQ
                                                      +--------- LN2 control, HV control

DAQ

The DAQ system is fully digitized with Pixie16 digitizer. The signals from the Clover and BGO are directly fed to the Pixie16 digitizers. The data processing library developed by Tim Gray can be found at https://github.com/belmakier/libpixie and https://github.com/belmakier/libClarionTrinity .

The Plx driver was modified from the Broadcom driver. The PixieSDK (legacy) was also modified.

Notice :

Detail of operation is needed.

LN2 cooling system

The liquid Nitrogen (LN2) filling system developed by Mitch Allmond (Oak Ridge) is hosted on the LN2-control computer under the account "ln@ln02".

ln@ln02 Directory

Several important directories for using the LN2 system are listed below.

/gln

/gln is the most important directory, it is where the control program is located and for most problems is where you will need to go

gln_ui

gln_ui is the user interface to issue commands to the fill program

gln_ui Commands

fill <det-list>: fill detectors <det-list> now
fill <det-list> after <number-of-minutes> (or <hours:minutes>): wait to fill detectors <det-list> by time <hours:minutes>
cool <det-list>: cool down detectors
ton <det-list>: turn on (enable fill for) detectors
tof <det-list>: turn off (disable fill for) detectors
con det#[.temp#]: turn on checking of detector temps
cof det#[.temp#]: turn off checking of detector temps
abort: abort and disable all fills

load [fig-file-name]: load configuration from fig-file-name (default = gln.fig)
exit-master: exit gln_master process

Warning :

This will stop the fill system

clr: clear all errors for entire system

Notice :

Proper usage is to clear individual detectors

clrd <det-list>: clear errors for specific detectors
clrs: clear all slot errors
clrm: clear all manifold errors
d: display status
dt: display times of all detectors & manifolds (formatted dates and times)
dts: display times of all detectors & manifolds (in seconds)
dc: display configuration (valve and ADC IDs, etc)
mon: enter monitor mode; type control-C to exit
quit: exit gln_ui process
hvln: useless command for backward compatibility
clear: clear screen
? or help: help text for commands

Low Level Commands

radc <#>: read ADC number <#>
opv <#> clv <#>: open and close valves

Warning :

Be careful with this

http://clarion02.physics.fsu.edu/~clarion02/index.html

List of Collaborators

From left: James Christie, Ram Yadav, Mitch Allmond, Tim Gray, photo taken by Vandana

The list may not be completed.

Name	Affiliation
Mitch Allmond	ORNL
Tim Gray	ORNL
Toby King	ORNL
Ingo Wiedenhoever	FSU
Sam Tabor	FSU
Vandana Tripathi	FSU
Lagy Baby	FSU
Soumik Bhattacharya	FSU
Caleb Benetti	FSU
Catur Wibisono	FSU
Samuel Ajayi	FSU
Ryan Tang	FSU
Ram Yadav	South Carolina State University
James Christie	UTK

Contact

References

↑ T. J. Gray et. al, NIM A 1041, 167392 (2022) https://doi.org/10.1016/j.nima.2022.167392
↑ C. J. Gross et. al, NIM A 450, 12 (2000) https://doi.org/10.1016/S0168-9002(00)00159-5

[1] T. J. Gray et. al, NIM A 1041, 167392 (2022) https://doi.org/10.1016/j.nima.2022.167392

[2] C. J. Gross et. al, NIM A 450, 12 (2000) https://doi.org/10.1016/S0168-9002(00)00159-5

[1]

[2]

Clarion2

Contents

Introduction