a device for detecting and measuring ionizing radiation, consisting of a tube containing a low-pressure gas and two electrodes between which a high voltage is maintained. The current between the electrodes is a function of the intensity of the radiation
ionization chamber in American English
any of various devices, as a closed vessel containing a suitable gas, for determining the intensity of X-rays or the disintegration rate of a radioactive material, by measuring the current flow between oppositely charged electrodes in the gas