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[History] [Revise]Monitor 4

The Monitor 4 Radiation Detector was used by Egon at the beginning of Ghostbusters II. While its exact purpose remains unclear, it appears to be calibrated to monitor emotions instead of radiation. It later appears on both Egon and Ray's belts during the montage.

Note the Monitor 4 in a pouch on the left.

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.


Monitor 4: Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick.

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

Typically ±15% of reading (referenced to Cs-137)

Internally mounted beeper (can be switched off for silent operation).

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)

178 grams (6.3 oz.) without battery

145 x 72 x 38 mm (5.7 x 2.8 x 1.5 in.)


The Monitor 4 is still listed as a rental prop from Modern Props.

This page was last edited by Alex Newborn on July 2, 2012, 5:17 am
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