Monitor 4 Handheld Radiation Alert® Detector

Product details (archived)

The information below is retained for reference only. This item is discontinued and cannot be ordered.

The M4 Handheld Radiation Alert Detector senses ionizing radiation by means of a GM (Geiger ) 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.

The M4 is a compact, general purpose survey meter 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.

Features:

• Visual and audio indication
• Geiger Mueller tube
• Battery operated
• Detects radiation over three selectable ranges
• Detects four different types of radiation:
  • X-ray
  • alpha
  • beta
  • gamma

Specifications:

• Detector: Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick
• Display: analog meter holds full scale in fields as high as 100X maximum reading
• 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 typica 75% detection efficiency
  • Detects gamma and x-rays down to 10 keV typical through the window, 40 keV minimum through the case. (GRAPH 1)
  • Normal background is 5-20 CPM
• Gamma sensitivity: 1000 CPM/mR/hr (referenced to Cs-137)

• Operating ranges:
  • 0 to 0.5; 0 to 5; 0 to 50 mR/hr
  • 0 to 500; 0 to 5,000; 0 to 50,000 CPM
  • 0 to 500 µSv/hr; 0 to 50 mR/hr
• Range Switch: X1, X10, X100 and Battery Check
• Accuracy: typically ±15% of reading (referenced to Cs-137)
• Audio: internally mounted beeper (can be turned off for silent operation)
• Power requirements: 9-volt alkaline battery
• Battery life: up to 2,000 hrs at normal background
• Temperature range: -4° F to 131° F (-20° C to 55° C)
• Weight: 7.9 oz (223.9 grams) without battery
• Operating Voltage :7 to 11vDC. (high and low voltage is fully regulated)
• Outputs: 3.5mm headphone jack with pulse out
• Size: 8.25" x 2.75" x 1.875" (210 x 70 x 48mm)

Supplied with:

• Carrying Case
• 1 year limited manufacturers warranty