Operational Check - LUDLUM MODEL 3 Technical Manual

Model 3
Ludlum Measurements, Inc.
Technical Manual
The same needle indications on successive ranges would be:
If you use the mR/hr scales, then the readings would be:
*This reading is using the bottom (non-linear) scale.
Many different dials are available, but each can be used as described above.

Operational Check

To assure proper operation of the instrument and detectors(s) between
calibrations, an instrument operational check including battery test and
instrument test (as described on pages 2-2 and 2-3) should be performed at
least daily or prior to use, whichever is less frequent. A reference reading
(or readings) with a check source should be obtained with the detector(s)
in a constant and reproducible manner at the time of calibration or at the
time the instrument is received in the field.
If at any time the instrument fails to read within 20% of the reference
reading when using the same check source, it should be sent to a
calibration facility for recalibration and/or repair. If desired, multiple
readings may be taken at different distances and/or with different sources
so that other ranges or scales are checked.
×1 = 4.2 kcpm (or 4200 cpm)
×10 = 42 kcpm (or 42,000 cpm)
×100 = 420 kcpm (or 420,000 cpm)
×0.1 = 0.13 mR/hr
×1 = 1.3 mR/hr
×10 = 13 mR/hr
×100 = 180 mR/hr*
Page 2-6
Section 2
April 2016