Mirion Technologies GEM-5 - Page 245

F4 – Faults
Gem-5 User’s Manual 229
Table 15 Troubleshooting Guide
Fault Error Possible Causes Fix
Detector missing
Address code missing
or incorrect
• Detector dipswitch
(ID) setting
• Detector Board
failure
• Detector Interface
bus incomplete
• Terminator
missing
• Check detector board
dipswitch
• Replace Detector
Board
• Check/replace ribbon
cable
• (re-)insert
Terminator board
Not calibrated Calibration zero
Calibration
efficiency value <1%
in detector setup
Calibrate detector
Low count rate
<50 cps (default for
large. Gamma det.);
optimize for location on
F3 – Setup, F3 –
Detection Zones, F2 –
Settings (and F5 –
Group Settings), “Low
Background Rate” for
Gamma groups and
detectors.
• Detector Board
failure
• Detector or PMT
damaged
• Replace Detector
Board
• Replace
detector/PMT
• Decrease Low
Background Rate
limit (below 50cps
default)
Excessive count rate >15,000 cps in detector
• Scintillator light
seal failure
• PMT noisy
• Preamplifier noisy
• HV circuit noisy
• Discriminator set
too low
• Discriminator
failure
• Repair detector light
seal
• Replace PMT
• Replace Detector
Board
• Replace Detector
Board
• Adjust discriminator
level
• Replace Detector
Board
HV Out of Range
(DAC vs ADC)
2%Full Scale
• Detector Board
failure
• HV overload
• Replace Detector
Board
• Disconnect PMT HV
cable, if the fault
disappears, replace
PMT and/or HV
divider