Dosimeter

A typical Geiger counter consists of a Geiger-Mueller tube, a visual readout, and an audio readout.  The Geiger-Mueller tube or detector is the heart of a Geiger counter.  It is a type of ionization chamber that counts particles of radiation.  That count is read by the user through a visual readout in the form of a traditional analog meter, or an electronic LCD (liquid crystal display) readout.  These meters are available in different units, including mR/hr, or milli-Roentgens per hour (popular in the US and Israel), and µSv/hr, or micro-Sieverts per hour (popular in Canada and overseas).