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| PRM-7000 / 8000 / 9000 Users Guide
Quicker response times are useful for locating objects and/or areas which are the source
of radiation levels that are above the normal background levels See Section “8.9 Low
AvWin” on page 18 for more information on the
Low AvWin
setting.
NOTE:
Because of the random nature of background and low-level radiation, it is
normal for the Current measurement to vary while observing the display. Also note
that the maximum value viewed on the Current display is averaged over the
Low
AvWin
setting of 5, 10 or 20 seconds. At low levels of less than 6.00 mR/hr, The
Maximum screen (discussed below) is the Maximum value measured and averaged
across one minute. It is normal that maximum values observed in the Current Mea-
surement display will likely differ from those recorded in the Maximum Measurement
display.
4.2
Average Measurement
This display indicates the Average dose rate level that has been measured since the de-
vice was turned on, or since the Average, Maximum, Minimum, Total and Elapsed Time
counters were reset.
This capability is very useful for determining the normal background radiation and
together with Maximum and Minimum Measurement displays (discussed below), for long
term monitoring of an area or an object.
The PRM Instrument is constantly counting all pulses from the Geiger tube and calculat-
ing the average by dividing the total count by the elapsed time and then compensating
through the calibration solver to accurately represent the average in the selected dose
rate units.
NOTE:
The Average, Maximum, Minimum and Total counters, as well as the Time/
Date of Maximum and Elapsed Time registers, are reset by any of the following:
1. The unit is powered on
2. A Hardware Reset is performed
3. The user resets the counters from the Utility menu
4. After the user performs a Timed Measurement
