Geiger counter

Geiger counter

Infobox Laboratory equipment
name = Geiger counter

caption = A modern geiger counter
acronym =
other_names = Geiger-Müller counter
uses = Particle detector
inventor = Hans Geiger
manufacturer =
model =
related = Geiger-Müller tube
A Geiger counter, also called a Geiger-Müller counter, is a type of particle detector that measures ionizing radiation.


Geiger counters are used to detect radiation, usually gamma and beta radiation, but certain models can also detect alpha radiation. The sensor is a Geiger-Müller tube, an inert gas-filled tube (usually helium, neon or argon with halogens added) that briefly conducts electricity when a particle or photon of radiation temporarily makes the gas conductive. The tube amplifies this conduction by a cascade effect and outputs a current pulse, which is then often displayed by a needle or lamp and/or audible . Modern instruments can report radioactivity over several orders of magnitude. Some Geiger counters can also be used to detect gamma radiation, though sensitivity can be lower for high energy gamma radiation than with certain other types of detector, because the density of the gas in the device is usually low, allowing most high energy gamma photons to pass through undetected (lower energy photons are easier to detect, and are better absorbed by the detector. Examples of this are the X-ray Pancake Geiger Tube). A better device for detecting gamma rays is a sodium iodide scintillation counter. Good alpha and beta scintillation counters also exist, but Geiger detectors are still favored as general purpose alpha/beta/gamma portable contamination and dose rate instruments, due to their low cost and robustness. A variation of the Geiger tube is used to measure neutrons, where the gas used is Boron Trifluoride and a plastic moderator is used to slow the neutrons. This creates alpha particle inside the detector and thus neutrons can be counted.

Types and applications

s. Some proportional counters can detect the position and or angle of the incident radiation as well. Other devices detecting radiation include:
ionization chamber,
semiconductor detectors and variants including CCDs,
microchannel plates,
scintillation counters, solid-state track detectors,
cloud chambers,
bubble chambers,
spark chambers,
neutron detectors and

The Geiger-Müller counter has applications in the fields of nuclear physics, geophysics (mining) and medical therapy with isotopes and x-rays. Some of the proportional counters have many internal wires and electrodes and are called multi-wire proportional counters or simply MWPCs. Radiation detectors have also been used extensively in nuclear physics, medicine, particle physics, astronomy and in industry.


Hans Geiger developed a device (that would later be called the "Geiger counter") in 1908 together with Ernest Rutherford. This counter was only capable of detecting alpha particles. In 1928, Geiger and Walther Müller (a PhD student of Geiger) improved the counter so that it could detect all kinds of ionizing radiation.

The current version of the "Geiger counter" is called the "halogen counter". It was invented in 1947 by Sidney H. Liebson (Phys. Rev. 72, 602–608 (1947)). It has superseded the earlier Geiger counter because of its much longer life. The devices also used a lower operating voltage. History of Portable Radiation Detection Instrumentation from the period 1920-1960

ee also

* Civil Defense Geiger Counters
* Geiger-Müller tube
* Radioactive decay
* Geiger plateau
* Gaseous ionization detectors
* Ionization chamber

External links

;PatentsElectric lamps and discharge devices of the Geiger-Müller type (Class 313/93)
* US patent|625823, K. Zickler, "Telegraphy by means of electric light"
* US patent|685958, N. Tesla, "Method of utilizing radiant energy"
* US patent|1589833, H. Benhken, "Measuring device for the examination of electromagnetic waves"
* US patent|1855669, O. Glasser, "Method and apparatus for the measurement of radiation intensity"
* US patent|1995018, H. J. Spanner, "Gas Filled Tube"
* US patent|2081041, H. Kott, "Apparatus for measuring radiation"
* US patent|2141655, H. Kott, "Radiation sensitive device"
* US patent|2145866, G. Failla, "Electrotechnique"
* US patent|2168464, S. Yeda, "Roentgenometer"
* US patent|2197453, G. L. Hassler, "Method of underground exploration"
* US patent|2221374, P. T. Farnsworth, "X-Ray projection device"
* US patent|2257827, G. J. Weissenberg, "Electron Discharge Tube"
* US patent|2397071, D. G. C. Hare, "Radiation detector"
* US patent|2397072, D. G. C. Hare, "Radiation detector"
* US patent|2397073, D. G. C. Hare, "Radiation detector"
* US patent|2397074, D. G. C. Hare, "Radiation detector"
* US patent|2397075, D. G. C. Hare, "Radiation detector"
* US patent|2398934, D. G. C. Hare, "Radiation detector"
* US patent|2440511, D. G. C. Hare, "Radiation detector"
* US patent|2449697, A. Graves, "Ionization chambers, Geiger Müller tubes, and the like"
* US patent|2397661, D. G. C. Hare, "Radiation detector"
* US patent|2521315, J. A. Victoreen, "Geiger tube"
* US patent|2542440, J. A. Victoreen, "Geiger tube"

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Look at other dictionaries:

  • Geiger counter — [gī′gər] n. [after H. Geiger (1882 1945), Ger physicist] an instrument for detecting and counting ionizing particles that pass through it: it consists of a needlelike electrode inside a hollow metallic cylinder filled with gas which, when ionized …   English World dictionary

  • Geiger counter — 1924, for German physicist Hans Geiger (1882 1945), who invented it with W. Müller …   Etymology dictionary

  • Geiger counter — ► NOUN ▪ a device for measuring radioactivity by detecting and counting ionizing particles. ORIGIN named after the German physicist Hans Geiger (1882 1945) …   English terms dictionary

  • Geiger Counter —    Hans Wilhelm Geiger (1882 1945) introduced the first successful counter of individual alpha rays through an instrument known as the Geiger counter. Geiger was bom at Neustadt an der Hardt, Germany. His father was a prominent rabbi and one of… …   Dictionary of eponyms

  • Geiger counter — Gei·ger count·er gī gər .kau̇n tər n an instrument for detecting the presence and intensity of radiations (as cosmic rays or particles from a radioactive substance) by means of the ionizing effect on an enclosed gas which results in a pulse that… …   Medical dictionary

  • Geiger counter — UK [ˈɡaɪɡə(r) ˌkaʊntə(r)] / US [ˈɡaɪɡər ˌkaʊntər] noun [countable] Word forms Geiger counter : singular Geiger counter plural Geiger counters physics a piece of equipment that finds and measures radioactivity …   English dictionary

  • Geiger counter — noun /ˈɡaɪɡə ˈkaʊntə,ˈɡaɪɡɚ ˈkaʊntɚ/ A device designed to detect radioactivity and measure its intensity. Figure 27 shows a Geiger counter, used to detect ionizing radiation. The counter consists of a thin central wire, carrying a positive charge …   Wiktionary

  • Geiger counter — [[t]ga͟ɪgə(r) kaʊntə(r)[/t]] Geiger counters N COUNT A Geiger counter is a device which finds and measures radioactivity …   English dictionary

  • Geiger counter — an instrument for detecting ionizing radiations, consisting of a gas filled tube in which electric current pulses are produced when the gas is ionized by radiation, and of a device to register these pulses: used chiefly to measure radioactivity.… …   Universalium

  • Geiger counter — /ˈgaɪgə kaʊntə / (say guyguh kowntuh) noun an instrument for detecting and counting ionising radiation, consisting of a tube which conducts electricity when the gas within is ionised by such a particle. Also, Geiger Müller counter. {from Hans… …   Australian English dictionary