Model 2363
Technical Manual
Section 6
Ludlum Measurements, Inc.
Page 6-3
January 2015
4. Move the PRESCILA to a 100 mR/hr
137
Cs field, set the selector
switch to “N” (neutron only), and adjust the neutron threshold
until a meter reading of 1.2 mrem/hr ±5% (corresponding to 450
cpm) is achieved. Do not adjust the threshold below -5 mV. If
necessary, switch to increasing the HV in 5-volt steps. Record this
reading.
5. Take the PRESCILA to an AmBe neutron field of 20 mrem/hr.
Adjust the calibration constant to calibrate the reading of the
meter to 20 mrem/hr. A typical conversion rate (as determined
by LANL) is 350 cpm per mrem/hr ±25%. Record and verify
that the following readings are within 10%: 2 and 5 mrem/hr, 20
and 50 mrem/hr, and 200 and 500 mrem/hr.
6. Take the Model 2363 to a
137
Cs range and change the selector
switch to “G” (gamma only). Adjust the gamma calibration
constant and dead time correction to calibrate the meter within
10% at the following fields: 2 and 5 mR/hr, 20 and 50 mR/hr,
and 200 and 500 mR/hr.
Maintenance
Instrument maintenance consists of keeping the instrument clean and
periodically checking the batteries and the calibration. The Model 2363
instrument may be cleaned with a damp cloth (using only water as the wetting
agent). Do not immerse instrument in any liquid. Observe the following
precautions when cleaning:
1.
Turn the instrument
OFF
and remove the batteries.
2.
Allow the instrument to sit for one minute before accessing
internal components.
Recalibration
Recalibration should be accomplished after maintenance or adjustments have
been performed on the instrument. Recalibration is not normally required
following instrument cleaning, battery replacement, or cable replacement.
