F3 – Setup Menu
Gem-5 User’s Manual 135
are red the test has passed.
To verify that this has been done, the intended method to check the Alarm
Test results is via the ALARMTST.CSV file (see Alarm Test Data Log
for a listing of the contents of this file).
For a successful test each detector should show at least 1 in the
contaminated columns (it not strictly necessary that the sum zones show
contaminated). In addition, the Maximum Rate columns should show
similar net rates for each detector.
A spreadsheet program can be used to examine the ALARMTST.CSV file
and more details can be found in the associated RESULTS...._AT.TXT
file.
Alarm Test Mode
Two options avaliable:
“Disabled” disables the Alarm Test function
“Gamma(3)” monitors with Gamma detectors
Measurement Variance Ratio Limit Exceeded
Choices are “Ignore” and “Notify Background Change” (default). See F3 – Setup,
F11 – Instructions, F11 – Alarm Test – Background Change setting for notification
text. This will display “Background Change” variation on the Alarm Test screen
when enabled.
Maximum Retests Allowed (Verification Test only)
If Initial count is outside of allowed range it is recounted this many time before being
marked Failed.
Count Time Minimum and Maximum (Verification Test only)
This is automatically calculated. The Minimum and Maximum settings force count
time within this range.
The formula for calculating count time is derived as per:
Equation 2 Expected Count Rate
(2)
Where:
R
E
= Expected Count Rate (cps)
ε = Efficiency (in fractional form)
A
S
= Source Activity (Bq)
V = Visible Area of Source (in fraction form, nominally 1 or 100%)
The statistical error of the background corrected activity for the check source is set
equal to Allowed Range of the known source activity: