free-air ionization chamber


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free-air ionization chamber

[¦frē ¦er ‚i·ə·nə′zā·shən ‚chām·bər]
(nucleonics)
An ionization chamber in which the ionizing radiation is limited by a diaphragm, so that ionization is detected in a region of accurately known volume, away from the electrodes and other internal parts of the equipment.
References in periodicals archive ?
The NIST Attix free-air ionization chamber [4] was also used to directly measure the air-attenuation corrections for various sources.
For a free-air ionization chamber standard with measuring volume V, the air-kerma rate, K, is determined by the equation
Aitken, An Analysis of the Free-Air Ionization Chamber for Extended Sources of Radiation, Phys.
Keywords: air kerma; free-air ionization chamber; primary standard; reference radiation qualities; medium-energy x rays; x-ray calibration.