The Monitor 4 Radiation Detector (M4) 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 senses ionizing radiation by means of a GM (Geiger Mueller) tube with a thin mica window.
The tube is enclosed inside the instrument. When a ray or particle of ionizing radiation enters or passes through the tube, it is sensed electronically and displayed by a red count light. When the switch is in the AUDIO position, the instrument will also beep with each radiation event. About 5 to 25 counts at random intervals (depending on your location and altitude) can be expected every minute from naturally occurring background radiation.
Detects alpha down to 2.5 MeV
Typical alpha 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
Detects gamma and x-rays down to 40 keV minimum through the sidewall
Normal background is approximately 10-20 CPM
1000 CPM/mR/hr (referenced to Cs-137)
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. |
Monitor 4 Energy Sensitivity: | 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. * 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 |
Monitor 4EC Energy Sensitivity 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 (referenced to Cs-137) |
Range Switch: | X1, X10, X100, Battery Check. |
Operating Range: | 0-.5, 0-5, 0-50 mR/hr and 0-500, 0-5,000, 0-50,000 CPM |
Accuracy: | ±10% of full scale (referenced to Cs-137). |
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 up to 2,000 hours at normal background radiation levels. |
Temperature Range: | -20° C to 55° C (-4° F to 131° F). |
Weight of the Monitor 4: | 178 grams (6.3 oz.) without battery |
Weight of the Monitor 4EC: | 198.1 grams (7 oz.) without battery |
Size: | 145 x 72 x 38 mm (5.7 x 2.8 x 1.5 inches). |
Includes: | Carrying Case, 1 year limited warranty, and CE mark |
Options: | Belt Clip |