Ludlum Measurements 2241-3, Руководство пользователя

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Model 2241-3 & 3i Technical Manual
Section 8
Ludlum Measurements, Inc. Page 8-3 January 2016
POSITION 1
:
DEAD TIME
(µs) allows changing the detector dead time
correction for the current detector setup. Setting this parameter to “0”
disables dead time correction. The dead time adjusts from 0 to 9999
microseconds (µs). The incoming counts are adjusted for dead time using
the following formula:
Where,
n = corrected counts per second
m = incoming count per second

= system dead time
POSITION 2
: calibration constant allows changing the calibration constant
for the current detector setup. The calibration constant (CC) adjusts from
0.001 to 280 × 10
9
. The calibration constant converts counts/time base to
units/time base. The CC must be set to 1 to readout in cps (counts per
second) or cpm (counts per minute).
CC CONVERSION TABLE
Conversion Rate Multiply by to get CC
cps/µR/hr 3.6 x 10
9
cps/mR/hr 3.6 x 10
6
cps/R/hr 3.6 x 10
3
cpm/µR/hr 6.0 x 10
7
cpm/mR/hr 6.0 x 10
4
cpm/R/hr 6.0 x 10
1
cps/µSv/h 3.6 x 10
7
cps/mSv/h 3.6 x 10
4
cps/Sv/h 3.6 x 10
1
cpm/µSv/h 6.0 x 10
5
cpm/mSv/h 6.0 x 10
2
cpm/Sv/h 0.6
Example:
The Model 44-9 GM detector produces approximately 3300
cpm/mR/hr for
137
Cs:

6.0 x 10
4
x 3300 = 198 x 10
6
for
CC.
n =
m
1 - m

CC =
cps x time base
rate