Geiger counter
A Geiger counter measures ionizing radiation. Geiger counters can detect photons, alpha, beta, and gamma radiation, but not neutrons. The sensor is a Geiger-MÃÂüller tube, a gas-filled tube that briefly conducts electricity when a particle or photon of radiation briefly makes the gas conductive. The instrument amplifies this signal and displays it to the user, either as a current measurement (needle, lamp) or an audible click.
Hans Geiger developed the Geiger counter in 1928. The current version of the Geiger counter is called the halogen counter. It was invented in 1947 by Sidney H. Liebson. It has superseded the Geiger counter because of its much longer life and lower operating voltage.
The Geiger-MÃÂüller tube is one form of a class of radiation detectors called gaseous detectors or simply gas detectors. Although useful, cheap and robust, a counter using a GM tube can only detect the presence and intensity of radiation.
The sensor contains a halogen quenched GM-counter tube which detects beta and gamma radiation with energies above 0.4 MeV. Each count event is accompanied by a short positive pulse (5V, 0.265 ms) on pin 1 of the BT connector. Each event is indicated visually by a flash of the LED on the sensor and accustically by a 3 kHz beep of 84.5 ms.
Gas detectors with the ability (due to their construction, gas filling, and associated electronics) to both detect radiation and determine particle energy levels are called Proportional counters. Some proportional counters can detect the position and/or angle of the incident radiation as well. Some of these have many internal wires and electrodes and are called multi-wire proportional counters or simply MWPCs, and have been used extensively in nuclear physics/medicine, particle physics, astronomy and in industry.
Other devices detecting radiation include: ionisation detectors dosimeters, semiconductor diode detectors and variants including CCDs, microchannel plates, scintillation counters, solid-state track detectors, cloud chambers, bubble chambers, spark chambers, neutron detectors and microcalorimeters.
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