SE International, Inc.:"The MONITOR 4 is a compact, general purpose survey meter capable of detecting alpha, beta, gamma, and x-rays over 3 selectable ranges. A red count light flashes and a beep sounds with each event detected.
SPECIFICATIONS
Detector
Monitor 4: Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick.
Display
Analog Meter Scale
Monitor 4 Energy Sensitivity
Detects alpha down to 2.5 MeV; typical detection efficiency at 3.6 MeV is > 80%.
Detects beta at 50 keV with typical 35% detection efficiency.
Detects beta at 150 keV with 75% typical detection efficiency.
Detects gamma and x-rays down to 10 keV typical through the window, 40 keV minimum through the sidewall of the detector.
Normal background is approximately 10-20 CPM.
Gamma Sensitivity
1000 CPM/mR/hr (referenced to Cs-137)
Operating Range
0-.5, 0-5, 0-50 mR/hr
0-500, 0-5,000, 0-50,000 CPM or 0-500 µSv/hr
0-50 mR/hr
Range Switch
X1, X10, X100, Battery Check
Accuracy
Typically ±15% of reading (referenced to Cs-137)
Audio
Internally mounted beeper (can be switched off for silent operation).
Anti-Saturation
Meter will hold at full scale in fields as high as 100 times the maximum reading.
Power Requirements
One 9-volt alkaline battery. Battery life is up to 2,000 hours at normal background radiation levels.
Temperature Range
-20° C to 55° C (-4° F to 131° F)
Weight
178 grams (6.3 oz.) without battery
Size
145 x 72 x 38 mm (5.7 x 2.8 x 1.5 in.)
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