General Survey Radiation Detector for 
Alpha, Beta, Gamma and X- Rays
Monitor 4 & 4EC
The Monitor 4  is a general purpose radiation survey detector alpha, beta, gamma and x-rays. The analog readout is displayed with a red count light and a beeper sounds with each count detected. Optional Sievert scale
energy range of radaition monitor
  • Halogen quenched uncompensated GM detector- 0.36 inch window
  • Alpha, Beta, Gamma and X-rays
  • Analog meter, CPM or tri-scale
  • x1, x10, x100 range switch
  • Audible beep
  • EC version for accurate linear reading above 40 KeV ( gamma and X-rays)
One sievert is equivalent to 100 rem; 
one microsievert (0.000001 Sv) = 0.0001 rem = 0.1 mR


Specifications Geiger Counter Model Monitor4 &4EC

Both Detect beta at 50 keV with typical 35% detection efficiency and beta at 150 keV with typical 75% detection efficiency.

Monitor 4:
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 case.

Monitor 4EC:
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.

 

Detector Monitor 4 Halogen-quenched, uncompensated Geiger Muller tube with thin mica window, 1.5-2.0 mg/cm2 . Approx 1000 CPM.mR/hr for Cesium 137.
Detector Monitor 4EC Halogen-quenched, uncompensated Geiger Muller tube Sidewall with 2mm tin filter, 1.5-2.0 mg/cm2. Approx 1000 CPM.mR/hr for Cesium 137.
Energy compensation only effective through the sidewall
Display: Analog meter CPM or Sievert
Accuracy:  ± 15% of full scale 
(Referenced to Cs-137)
Energy Sensitivity  
Alpha Detects alpha down to 2.5 meV. Typical detection efficiency at 3.6 meV is greater than 80%
Beta Detects Beta at 50 KeV with typical 35% efficiency
Detects Beta at 150 KeV with typical 75% efficiency
Gamma and X-ray Detects Gamma and X-rays down to 10 KeV through the window and
40 KeV maximum through the side wall
Normal background is ~ 10-20 CPM, Gamma sensistity ~ 1000 CPM/mR/hr
EC Version As above except the energy response through the detector is flat within 61% or - 26% over the range 40KeV to 100 KeV
and within the range +35% or -17% over the range 100 KeV to 1.4 MeV (referenced to Cs-137)
Operating Range CPM 0-500, 0 - 5000, 0 - 50,000
mR/hr - 0-0.5, 0- 5, 0- 50 mR/hr
µSv/hr - 0- 500, )-50 mR/hr (optional scale)
Count Light Red LED flashes with each radiation event.
Audio Indicator 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 min. 2000 hours at normal background radiation levels.
Temperature Range -20ºC to 55ºC (-4ºF to 131ºF)
Weight ~ 224 grams (8 oz.) without battery.
Size 210 x 70 x 48 mm (8.25 x 2.75 x 1.875 in.).

 

Ordering Information
Model  
Monitor 4 Standard Monitor4: Includes carrying case, 1 year limited warranty and CE mark. (Batteries not included) $389.00
Monitor 4 USB Includes observer software and USB cable $459.00
Monitor 4EC Monitor4 EC energy compensated side wall detector, 2 mm tin filter $430.00
Monitor 4EC-USB Includes observer software and usb cable $499.00
For sievert scale add SV to part #

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