Clarion2

Image of Clarion2, photo by Tim.

Introduction

Clarion2 is the successor of Clarion (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. Please ask Raeed Nawaf for an updated model here: rn24b@fsu.edu

Clarion02 Geant With BGO

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.

Casual Tutorial For Getting a Pixie Crate Up and Running

This is meant to be a bit of a tutorial on how to get a Pixie16 crate running from a fresh flash of Ubuntu 18.

Prerequisites

Make sure that you have at an XIA crate with at least one Rev. F Pixie16 board. Rev. F boards can be recognized by the female headers on the face instead of the male. Rev. D boards have the male, there are several floating around Fox Lab.

Make sure that you have a matching pair of optical communication boards: one to go in the crate and one to go into the PC. These model numbers should match or be close. For example, I had to use a PCI-8331/8336 board in the PC and a PXI-8336 board in the crate. It will not work if there is a mismatch. Trust me.

Make sure you are running Ubuntu 18 with kernel 4.15. The drivers will work with this setup only.

Installation

The install here is a bit of a lie. In your home directory copy the entire ~/pxi/ folder from the Clarion02 DAQ PC. All following instructions are on the local PC.

Navigate to cd ~/pxi/PlxSdk/ Once here give the commands:

make clean make

This will build a bunch of stuff. Next, navigate to the Drivers folder: cd ~/pxi/PlxSdk/Drivers

I had the most luck with the "builddrivers.sh" script.

Start with the PCI drivers: ./builddrivers Svc

This will likely throw some errors. If it does find the Dispatch.c script is it complaining about, probably here: ~/pxi/PlxSdk/Driver/PlxSvc/

Edit the includes to look like this:

... I need to find the script so that I can copy the header.... Bad me

LeCroy HV Mainframe

The clovers and BGOs bias is supplied by two LeCroy 1458 HV Mainframes. These are controlled via a serial connection to the LN02 PC.

Clearing Panic Status

A panic status seems to happen with the loss of power. If the system is in a Panic state, the red LEDs on both sides of the "PANIC OFF" button will be on. To clear the Panic status:

1. Turn key to "Local"
2. Press the "HV Off" button. This should clear the status and make the red panic lights go out.
3. TURN THE KEY BACK TO REMOTE!!! This is important so we can control the system via the serial connection.

You will need to do this procedure for each mainframe.

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".

Changing Alert List

To change the alert list, edit ~/scripts/run-send-alarms.sh with the relevant emails.

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

Clover Inventory

Clover Position / Name	"Owner"	Most Recent Pump	Heat Applied at Pump?
A1	ORNL	?	?
B2	ORNL	?	?
C3	ORNL	?	?
D4	ORNL	?	?
E5	FSU	January 13, 2026	?
F6	Not Real	?	?
G7	FSU	January 13, 2026	?
H8	ORNL	?	?
I9	FSU	?	?
J10	FSU	?	?
K11	ORNL - Gone but not forgotten	?	?

Contact

• Mitch Allmond mailto:allmondjm@ornl.gov
• Tim Gray mailto:graytj@ornl.gov
• Vandan Tripathi mailto:vtripath@fsu.edu