Since our instruments are sometimes purchased by individuals with no background in radiation protection, we thought it would be helpful to include this information. The following information is based on features of most of our Radiation Alert meters.
Some tubes have a thin mica window.
When a ray or particle of ionizing radiation enters or passes through the tube, it is sensed electronically and displayed on the meter or LCD and by a red count light. Some detect only gamma and x-rays. They are calibrated to Cesium 137, but also serve as excellent indicators for many other sources of ionizing radiation. The window of the GM tube is very thin mica. This mica window is protected by a screen.