PCM-2 Manual.pdf - Voss Associates

ALPHA RDA UPPER LIMiT (DPS): 25,,0
BETA RDA UPPER LIMIT (DPS): 150
ALPHA SENSITIVITY: 0.050
BETA SENSITIVITY: 0.10
RDA CON FIDENCE: 95%
COUNT TIME (SEC): 1.00
SI G~1A FACTOR: 4.00
BACKGROUND SIGMA FACTOR: 4.00
ALPHA SUM ZONE ALARM (DPS): 23.3
BETA SUM ZONE ALARM (DPS): 117
ALPHA SUN CH ALARM (DPS): 83.3
BETA SUM CH ALARM (DPS): 500
~-calculated Values~~~~~~~~~===91
'/IA)( ALPHA CHANr~EL RDA (DPS): 2.56
MAX BETA CHANNEL RDA (DPS): 17.9
FALSE ALARM RATE (%): 0.19
~
Alpha & Beta
RDA Upper Limits
Alpha & Beta
Sensitivities
RDA Confidence
Count Time
Sigma Factor
Background
Sigma Factor
These are the maximum acceptable values for Reliably Detectable Activities. If
changes in background count rates raise the calculated RDA for any channel(s)
above these limits, a high background alarm is posted.
A ratio above and below the mean of background counts beyond which a single
detector's background is determined to be indicative of a detector failure. The
default value is 0.5 for the beta channels, meaning that a detector with more than
twice or less than half as many counts as the system average is considered
suspect. Note that because the size, location and orientation of a detector affects
its background counts, each detector has a Geometry Factor which is used to
compensate for these variables. The default alpha sensitivity factor is 0.10.
This is the probability of detecting contamination of the specified RDA. Possible
values are 50 %, 75 %, 90 %, 95 %, 99 % and 99.9 %. Refer to the manual section
on statistical algorithms for a detailed discussion of this parameter.
The time (in seconds) for which all channels of the PCM-2 will count.
A multiplier of the background count rate standard deviation which influences the
false alarm rate. Refer to Appendix A on statistical algorithms.
If a background update count differs from the stored average background rate by
this many standard deviations, the new rate will inunediately replace the old. If
the detector(s) on which this occurs alarmed on the last measurement, they are
assumed to be contaminated.
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rCM2.MAN/ nev A/AIJI iI 1995