When exposed to radiation, some of this positive charge is neutralized by ions created by the radiation. The dosimeters are read directly or by being placed in the charger-reader to determine the actual radiation dose received. Pocket dosimeters look like pens, and are clipped onto a shirt pocket. Beta and Gamma Radiation Detectors Radiation detectors are devices used to detect beta and gamma radiation in air. They differ from dosimeters in that they can measure radiation directly, in real time.
Most radiation detectors detect the interaction of radiation with gas molecules.
As radiation slows down in a gas, it ionizes gas atoms by ejecting electrons from them and leaving behind positive ions. On the other hand, the output of scintillation counters and gas flow proportional counters is proportional to the amount of energy deposited in the detector. A Geiger counter can count beta particles and gamma rays. The tube contains an inert gas such as helium or neon. The process of measuring a source of radiation begins by holding the Geiger counter near the source.