Analog Radiation Detector

The M4 and M4EC are compact, 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)

Specifications

• Detector :Monitor 4: Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick. Monitor 4EC: Halogen-quenched GM tube, energy compensated sidewall 2mm tin filter. Thin mica window 1.5-2.0 mg/cm2 thick.
• Display :Analog Meter holds full scale in fields as high as 100X max reading.
• Operating Range : 0-50 mR/hr and 0-500, 0-5,000, 0-50,000 CPM or 0-500 µSv/hr 
• Monitor 4 Energy Sensitivity : M4: Detects alpha down to 2.5 MeV; typical detection efficiency at 3.6 MeV > 80%. Detects beta at 50 keV with 35% efficiency. Detects beta at 150 keV with 75% efficiency. Detects gamma and x-rays down to 10 keV through the window, 40 keV minimum through the sidewall. Normal background is approximately 10-20 CPM.
  M4EC: 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.
• Range Switch : X1, X10, X100
• Accuracy : ±15% of full scale (referenced to Cs-137)

• Gamma Sensitivity : : 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.
• Operating Range :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.
• Range Switch :X1, X10, X100, Battery Check.
• Accuracy : Typically ±15% of reading (referenced to Cs-137)

Monitor 4	Monitor 4EC

Features

• Audio: Internally mounted beeper (can be turned off for silent operation).
• Power Requirements: 9-volt alkaline battery up to 2,000 hrs at normal background
• Temperature Range: -20° C to 55° C (-4° F to 131° F).
• Weight: M4: 223.9 grams (7.9 oz) without battery, M4EC: 245.7 grams (8.7 oz) without battery
• Outputs: 1/8 inch headphone jack with pulse out.
• Size: 210 x 70 x 48 mm (8.25 x 2.75 x 1.875 in.)
• Accessories: Carrying Case, Observer Software, USB Option, SI Meter Option
• Warranty: 1 year limited warranty
• Monitor 4 Kits: Build your own Monitor 4! Learn about how a geiger counter works!

Accessories

• Carrying Case : 
• Observer Software : 

Support

• Monitor 4 & 4EC Operation Manual

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