Radiation Monitor Troubleshooting and FAQs

This sensor is no longer available. Information is presented for reference only.

Primary Test: Is the 9 V battery good? Are the correct settings chosen on the sensor? Are the monitor and source positioned properly for the type of radiation to be detected?
⚬ Alpha: position the monitor so the suspected source of radiation is next to the GM window.
⚬ Beta: point the end window toward the source of radiation.
⚬ Gamma: hold the back of the Radiation Monitor toward the source of radiation.^*
Secondary Test: Some types of radiation are very difficult or impossible for this GM tube to detect. Beta emissions from tritium are too weak to detect using the Radiation Monitor. Americium-241, used in some smoke detectors, can overexcite the GM tube and give an indication of a higher level of radiation than is actually there.

^* Low-energy gamma radiation (10-40 KeV) cannot penetrate the side of the GM tube, but may be detected through the end window.

Sensor: LND 712 halogen-quenched GM tube
⚬ mica window thickness, 1.5 to 2.0 mg/cm²
⚬ Rated at 1000 counts per minute using a Cesium-137 laboratory standard.
Power: One 9-volt alkaline battery provides a battery life of 2000 hours at normal background radiation levels.
Accuracy
⚬ Non-instrumental aligned, approximately ±20% of full scale.
⚬ Instrumental aligned, approximately ±10% of full scale.
Dimensions: 38 X 62 X 145 mm (1.5 X 2.8 X 5.7 in)
Weight: 245 g (8.8 oz) with battery installed
Energy Sensitivity
⚬ Alpha: Down to 2.5 MeV; typical detection efficiency at 3.6 MeV is greater than 80%.
⚬ Beta: 50 KeV, typical 35% detection efficiency.
⚬ Gamma and X-rays: Down to 10 KeV typical through the end window, 40 KeV through the case.
Audio Output: Audible indication of each count available using the Audio switch position.
Temperature Range: 0 to 50 °C

It is not necessary to calibrate this sensor.