Page 813 - Radiation Safety

Semiconductor Detector

• Radiation is measured by means of the number of charge

carriers set free in the detector, which is arranged between

two electrodes.

• Ionising radiation produces free electrons and holes. The

number of electron-hole pairs depends on the energy

transmitted (intensity) by the radiation to the semiconductor.

• As a result, a certain number of electrons are transferred

from the valence band to the conduction band, and an

equivalent number of holes are created in the valence band.

•Under the influence of an electric field, electrons as well as

holes travel to the electrodes, where they give rise to a

pulse that can be measured in an outer circuit.