Ludlum Measurements 25024424, Manual

Page: 31 / 91

5.7. COUNT MODE 27
Figure 5.4: MAX mode display.
5.7 COUNT Mode
The purpose of COUNT mode is to count for a predetermined amount of time, and to show
the results on the display. Note that the predetermined count time can be from 1 second to
3600 seconds, or can be set to zero to enable continuous counting until stopped by the user.
The instrument is equipped with seven unique count times (one user defined time, 0 [con-
tinuous count], 6 seconds, 30 seconds, 60 seconds, 2 minutes, 5 minutes, and 10 minutes)
that are selectable in COUNT mode by performing a long press (press and hold for approxi-
mately 0.5 seconds) of the MODE button.
Count mode operation is very flexible, depending on the units chosen. A common choice is
for the count mode to perform a scaler count for a specified time, with a resulting answer in
counts (equaling detected radiation events). If the count units chosen are cpm or cps, then
the resulting answer is an averaged count rate over the time interval.
Other choices are to have count mode units of R/h, Sv/h or rem/h, in which case the COUNT
mode results in a averaged exposure or dose rate. But if count mode units of R, Sv, or rem are
chosen, the result is shown in accumulated exposure or accumulated dose over the chosen
count time.
Activity measurements that utilize the efficiency parameter for 2pi, 4pi, etc. can also be se-
lected. The Bq and dpm units will result in an average activity over the count time. The count
(c) disintegrations (d) will sum the total activity (efficiency corrected) over the count time.
The following table lists the possibilities:
Table 5.1: COUNT mode uits
UNITS RESULT
c counts per count time
d disintegrations per count time
cpm, cps count rate, averaged over the count time
dpm, Bq disintegration rate, averaged over the count time
R, Sv, rem integrated exposure or dose over the count time
R/h, Sv/h, rem/h exposure or dose rate, averaged over the count time
When entering COUNT mode or changing units within COUNT mode, the current display
units will be displayed for approximately one second.
June 2022