S.E.International Monitor 4-Handheld l Radiation Alert® Detector
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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. Gamma sensitivity is typical of a pancake G-M
detector: 1000 CPM/mR/hr (referenced to Cs-137).
Monitor 4 Survey Meter 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 greater than 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)
Energy Sensitivity for the 4EC is the Same as Monitor 4 except the
energy response for gamma and x-rays through the detector sidewall
is flat within +61% or -26% over the range of 40 keV to 100 keV, and
within +35% or -17% over the range of 100 keV to 1.3 MeV.
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
±15% of full scale (referenced to Cs-137)
S.E. International Monitor 4
Response Curve

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
M4: 178 grams (6.3 oz.) without battery
Size
145 x 72 x 38 mm (5.7 x 2.8 x 1.5 in.)
Warranty
1 year limited warranty