LUDLUM MODEL 3 User Manual

Model 3 Technical Manual Section 2
Ludlum Measurements, Inc. Page 2-4 April 2016
The same needle indications on successive ranges would be:
×1 = 3.5 kcpm (or 3500 cpm)
×10 = 35 kcpm (or 35,000 cpm)
×100 = 350 kcpm (or 350,000 cpm)
A typical dual scale (two arcs) meter face is shown below. The top scale
reads 0-2 mR/hr. The bottom scale also reads 0-2 mR/hr and is for ×100
only scale. The ×100 ONLY scale will work correctly when the multiplier
switch is in the ×100 range. The meter face also has a BAT TEST position
on the dial.
If the needle is pointing as indicated below and the range selection switch
is on the ×0.1 scale, then the reading is 0.1 mR/hr.
The same needle indications on successive ranges would be:
×1 = 1.0 mR/hr (or 1000 µR/hr)
×10 = 10 mR/hr (or 10,000 µR/hr)
×100 = 70 mR/hr (or 70,000 µR/hr)

LUDLUM MODEL 3 Specifications

General

Detector Compatibility	scintillation detectors
Power Source	Two D-cell batteries
Display	Analog meter
Audio	Built-in speaker
Operating Temperature	-20°C to 50°C (-4°F to 122°F)
Energy Range	Depends on detector
Accuracy	±10%