PCM-2 Manual.pdf - Voss Associates

WF= Weight Factor
R new = The most-recently measured (real) background count rate,
measured in a single count time interval.
Beta Shield Factor
When the instrument is occupied, some detectors may be shielded from local
radiation sources which account for part of the observed background. The shield
factor is defined as background while occupied divided by background while
unoccupied. Note: Alpha channel shield factors are always equal to 1.
The following values are displayed, but may not be edited:
Alpha & Beta
Background
Alpha & Beta
Alarm Level
Alpha & Beta
Count Time
The current background count rates for this detector.
Net count rates (above background) at which this detector will alarm based on the
current background, RDA, RDA confidence level, sigma factor, etc.
The count times calculated for the alpha and beta channels of this detector given
the current RDA, RDA confidence level, sigma factor and background count
rates.
Hand Probe Parameters
If the hand probe option is installed, this screen may be used to set its high
voltage, alpha and beta thresholds and alpha and beta alarm setpoints. An alarm
setpoint may be entered for both the alpha and beta channels. This setpoint is
expressed in the count rate units selected for the PCM-2 (CPS or CPM). In
addition, a weighing factor and a background sigma factor may be entered for
both the alpha and beta channels. These parameters are used in a "smoothing"
algorithm which has been incorporated for the hand probe readings to allow the
user to control the reponse time and the step change for the hand probe readings.
HIGH VOLTAGE (VOLTS): 1550
Hand Probe Parameters
~ALpha Channel
Beta ChanneL
THRESHOLD (% MAX):
ALARM SETPOINT (NCPS)
45
61.6
THRESHOLD (% MAX):
ALARM SETPOINT (NCPS)
5
9.50
Measured VaLue
BACKGROUND (CPS): 0.032
Measured VaLue
BACKGROUND (CPS): 6.19
PCM2.MANI REV AI April 1995 5-13