The ionization chamber is the simplest type of gaseous ionisation detector, and is widely used for the detection and measurement of many types of ionizing radiation, including X-rays, gamma rays, alpha particles and beta particles. Conventionally, the term "ionization chamber" refers exclusively to those detectors which collect all the charges created by direct ionization within the gas through the application of an electric field. It uses the discrete charges created by each interaction between the incident radiation and the gas to produce an output in the form of a small direct current. This means individual ionising events cannot be measured, so the energy of different types of radiation cannot be differentiated, but it gives a very good measurement of overall ionising effect.
Two high pressure cylindrical ion chambers in an enclosure.
Ionization chamber made by Pierre Curie, c 1895-1900
Hand-held integral ion chamber survey meter in use
View of sliding beta shield on integral hand held instrument
Gaseous ionization detector
Gaseous ionization detectors are radiation detection instruments used in particle physics to detect the presence of ionizing particles, and in radiation protection applications to measure ionizing radiation.
The generation of discrete Townsend avalanches in a proportional counter.
Visualisation of the spread of Townsend avalanches by means of UV photons