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It has a good uniform response to radiation over a wide range of energies and is the preferred means of measuring high levels of gamma radiation, such as in a [[hot cell|radiation hot cell]] as they can tolerate prolonged periods in high radiation fields without degradation.
They are widely used in the nuclear power industry, research labs, [[fire detection]], [[radiation protection]], and [[environmental monitoring]].
==Principle of operation==
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====Sealed low-pressure chamber====
These are similar in construction to the vented chamber, but are sealed and operate at or around atmospheric pressure. These chambers also have the advantage of not requiring a vent and desiccant. To improve detection efficiency, they are filled with a [[noble gas]] because the highly [[electronegative]] oxygen in air easily captures free electrons, forming negative ions. The strength of the beta window limits the differential pressure from atmospheric pressure that can be tolerated, and common materials are stainless steel or titanium with a typical thickness of 25
====High-pressure chamber====
[[File:Ionizacni komory v dozimetru.jpg|thumb|Two
The efficiency of the chamber can be further increased by the use of a high-pressure gas. Typically a pressure of 8-10 atmospheres can be used, and various noble gases are employed. The higher pressure results in a greater gas density and thereby a greater chance of collision with the fill gas and ion-pair creation by incident radiation. Because of the increased wall thickness required to withstand this high pressure, only gamma radiation can be detected. These detectors are used in survey meters and for environmental monitoring.<ref name=radpro/>
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====Extrapolation chamber====
Similar in design to a parallel plate chamber, the upper plate of an extrapolation chamber can be
==Instrument types==
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===Nuclear industry===
Ionization chambers are widely used in the nuclear industry as they provide an output that is proportional to [[radiation dose]]. They find wide use in situations where a constant high dose rate is being measured as they have a greater operating lifetime than standard Geiger–Müller tubes, which suffer from gas break down and are generally limited to a life of about 10<sup>11</sup> count events.<ref name=knoll/>
Additionally, the Geiger–Müller tube cannot operate above about 10<sup>4</sup> counts per second, due to dead-time effects, whereas there is no similar limitation on the ion chamber.
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