Ludlum Measurements 2241-3, Manual

Page: 40 / 77

Model 2241-3 & 3i Technical Manual
Section 8
Ludlum Measurements, Inc. Page 8-11 January 2016

Adjust the pulser amplitude to 1.5 times the Model 2241-3
discrimination level.

Adjust the pulser output to 800 cpm and confirm that the Model
2241-3 reads 800 cpm
±
10% on the ratemeter setting.

Adjust the pulser output to 200 cpm and confirm that the Model
2241-3 reads 200 cpm
±
10% on the ratemeter setting.

Adjust the pulser output to 800 cpm, take a one minute count and
confirm that the digital scaler readout displays 800 cpm
±
2%.

Adjust the pulser output to 200 cpm, take a one minute count and
confirm that the digital scaler readout displays 200 cpm
±
2%.
 Confirm that the 20% and 80% readings for the upper decades are
within the pulser input by decading the pulser count output.
 Confirm that the scaler readout is within 2% of the pulser input rate.
 Ensure that the
ALERT
and
ALARM
s function by inputting the preset
alarm levels as to initiate the alert and alarm conditions.
R/hr C
ALIBRATION
The following calibration procedure assumes that detector Calibration
Constant (CC) and Dead Time Constant (DTC) are already known. If these
constants must be determined, reference the following subsection,
“Determining CC and DTC.”
Switch the toggle switch to
DET
2. Detector setup number “1” is usually
reserved for the Counts/minute parameter calibration. Rotate the
FUNCTION
switch counterclockwise to position 1 and enter the detector
Dead Time in µs. Rotate to position 2 and enter the Calibration Constant.
Enter the desired parameters for positions 3-F. Switch to position 0 for
normal operation.
Expose the detector to calibrated radiation fields extending from the lower
to the upper operating range of the detector. Confirm that the linearity is
within 10% of each respective reading. If the readings are off on the lower
detector operating region, vary CC. If the readings are off at the upper end
of the detector operating region, adjust DTC.