Geigermaß

Geigermaß is a term used in German-language contexts to refer to the reading displayed by a Geiger counter. It denotes the rate at which ionizing events are detected by the instrument and is typically expressed in counts per minute (CPM) or counts per second (CPS). In casual usage, some people treat Geigermaß as a direct measure of dose rate, but converting it to dose requires calibration because the relationship between count rate and absorbed radiation dose depends on the radiation type, energy spectrum, and detector efficiency.

Measurement principle: A Geiger counter contains a Geiger–Müller tube. When ionizing radiation produces an ionization event inside the tube, a short electrical pulse is generated and counted by the device. The reported Geigermaß is the total number of pulses per unit time, often averaged over a short interval to smooth fluctuations.

Calibration and interpretation: To relate CPM/CPS to dose equivalent (for example μSv/h), devices are calibrated with standard radiation sources and use a conversion factor that varies with energy. Background radiation contributes to the Geigermaß, so background counts are typically subtracted for more accurate readings. At high count rates, the detector’s dead time can cause undercounting.

Applications and limitations: Geigermaß is widely used in public safety, industrial monitoring, and hobbyist settings as a rough indication of radiation presence and intensity. It does not provide energy-specific information and cannot distinguish radiation types; precise assessment of risk or source activity requires more specialized instrumentation and calibration.

History: The Geiger counter was developed by Hans Geiger and Walther Müller in the 1920s, and the shorthand term Geigermaß has emerged in informal contexts to describe the device’s readout.