Thermo Scientific SAM12, Manual

Page: 103 / 176

Issue: 1.0 Operating Instructions
Thermo Fisher Scientific SAM12 User Manual 5-63
Amplifier “dead-time”, a High Background fault condition will
also be enforced. Monitoring of articles cannot be performed
unless one or more of the following occurs:
1. The background activity drops sufficiently for the
current alarm level to be detected, or,
2. The Health Physicist modifies one or more of the
following parameters:
•
Increases the maximum monitoring time - see
Params 2 (page 5-10) .
•
Relaxes the Probability of Detection - see Params 2
(page 5-10) .
•
Relaxes the Probability of False Alarm - see Params
2 (page 5-10) .
•
Raises the Normal Alarm level - see Alarms (page
5-12) .
Minimum Detectable Activity (MDA) and High Background
Criterion (page 6-7)
describes how the SAM12 decides if a
high background condition exists.
The "Out Of Service –
Temporary Error has Occurred"
if Low Background conditions
exist.
“Out of Service – Low Background Counts Top Detector”
message is displayed when the count rate in the gross counts
window over the 10 second background check period on any
single detector falls below the threshold. It will remain in this
state until the background count rate once again exceeds the
threshold on all detectors.
Notes regarding Low
Background