|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.
Typically ±15% of reading (Cs137)
The M4 and M4EC are compact, ergonomic, general
purpose survey meters 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. The Monitor 4EC offers a more linear
reading for gamma and x-rays (above 40 keV).Click here for Original Monitor 4. Click here for USB Model.
Monitor 4: 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.).
Monitor 4EC: Halogen-quenched GM tube, energy
compensated sidewall 2mm tin filter. Thin mica window
1.5-2.0 mg/cm2 thick. Effective diameter of window is 9.1 mm (.36 in.).
Analog Meter holds full scale in fields as high as 100X
maximum reading. CPM & mR/hr scale. Optional SI
Scale Meter Available
1000 CPM/mR/hr (Cs137). 4EC is the same as M4
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.
M4 & M4EC meter scales shown above.
Both Detect beta at 50 keV with typical 35% detection efficiency and beta at 150 keV with typical 75% detection efficiency.
Detects alpha down to 2.5 MeV; typical detection efficiency at 3.6 MeV is greater than 80%.
Detects gamma and x-rays down to 10 keV typical through the window, 40 keV minimum through the
Detects alpha down to 2.5 MeV; typical detection
efficiency at 3.6 MeV is greater than 80%. Detects gamma and x-rays down to 10 keV typical through the window (non-compensated), 40 keV through the sidewall.
Monitor 4 End Window
Internally mounted beeper (can be turned
off for silent operation).
9-volt alkaline battery. Approx. 2,000 hrs. at
-20° to 55°C (-4° to 131°F)
M4: 200 g (7.1 oz)
M4EC: 224 g (7.9 oz)
3.5 mm headphone jack with pulse out.
209 x 71 x 50 mm (8.2 x 2.8 x 1.9 in.)
Carrying Case w/ Belt Clip
SI Meter Option, Observer Software, Mini-USB Option w/ USB Observer Software
1 year limited warranty
Monitor 4 Kits
Build your own Monitor 4! Learn about how a geiger counter works!
Monitor 4 & 4EC Operation Manual (pdf)| English | Spanish | French | Quick Specs