The Monitor 4 is compact, analog radiation detector. A general purpose survey meter capable of detecting alpha, beta, gamma, and x-rays over 3 selectable ranges. Proven and reliable over decades of use in the industry, the Monitor 4 has evolved into one of the best analog radiation detectors of today. Simple and ergonomic , a red count light flashes and a beep sounds with each count detected. Battery check and silent operation with the flick of your thumb.
Applications & Uses: Checking industrial gauges, such as moisture, density, or level gauges containing Cesium-137, Locating Sources, Personal protection, General surveying
Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick.
Effective diameter of window is 9.1 mm (.36 in.).
0-.5, 0-5, 0-50 mR/hr
0-500, 0-5,000, 0-50,000 CPM
or 0-5, 0-50, 0-500 μSv/hr (SI Scale Meter Option)
X1, X10, X100, Battery Check.
1000 CPM/mR/hr (Cs137).
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 and beta at 150 keV with typical 75% detection efficiency. Detects gamma and x-rays down to 10 keV typical through the window, 40 keV minimum through the case.
Reference to Cs137
Typically ±15% from factory, ±10% with NIST Source Calibration NIST Calibration Additional
Analog Meter holds full scale in fields as high as 100X maximum reading. CPM & mR/hr scale. Optional SI Scale Meter Available
Internally mounted beeper (can be turned off for silent operation).
3.5 mm jack with pulse out.
9-volt alkaline battery (included). Approx. 2,000 hrs. at normal background
-10° to +50°C (14° to 122°F)
10% to 70% Non-Condensing.
M4: 200 g (7.1 oz) M4EC: 224 g (7.9 oz)
209 x 71 x 50 mm (8.2 x 2.8 x 1.9 in.)
Carrying Case w/ Belt Clip
SI Meter Option, Observer Serial Software
1 year limited warranty
Included With Monitor 4