The radiation detector is standard industrial model of a Geiger-Müller tube with a thin mica output window.
It is factory-calibrated using a pulse generator and is the standard ±15% of the full scale relative to Cesium-137.
It offers reliable results in milliroentgens/hour and events/minute (cpm) in three different periods. The unit is protected by an anti-saturation circuit up to a value equivalent to 100 times the maximum reading in the greatest interval. The radiation detected is indicated by the graduated scale, a blinking LED and an acoustic signal.