An ionization chamber is a radiation detector used to measure the intensity of a radiation beam or to count individual charged particles. It consists of a gas-filled cavity surrounded by two electrodes of opposite polarity and an electrometer. The electric field between the electrodes accelerates the ions produced by the radiation, which are then collected by the electrodes. This charge is read by the electrometer and can be converted into absorbed dose.
The gas amplification curve describes how an ionization chamber behaves in response to an applied voltage.