Detectors

X ray detectors vary in shape and function depending on their purpose. Imaging detectors such as those used for radiography were originally based on photographic plates and later photographic film but are now mostly replaced by various digital detector types such as image plates or flat panel detectors. For radiation protection direct exposure hazard is often evaluated using ionization chambers, while dosimeters are used to measure the radiation dose a person has been exposed to. X ray spectra can be measured either by energy dispersive or wavelength dispersive spectrometers.