Editing Semiconductor detector (section)

== Detection mechanism ==
In semiconductor detectors, ionizing radiation is measured by the number of [[charge carrier]]s set free in the detector material which is arranged between two [[electrode]]s, by the radiation. Ionizing radiation produces free [[electron]]s and [[electron hole]]s. The number of electron-hole pairs is proportional to the energy of the radiation to the semiconductor. As a result, a number of electrons are transferred from the [[valence band]] to the [[conduction band]], and an equal number of holes are created in the valence band. Under the influence of an [[electric field]], electrons and holes travel to the electrodes, where they result in a pulse that can be measured in an outer [[electrical network|circuit]], as described by the [[Shockley-Ramo theorem]]. The holes travel in the opposite direction and can also be measured. As the amount of energy required to create an electron-hole pair is known, and is independent of the energy of the incident radiation, measuring the number of electron-hole pairs allows the energy of the incident radiation to be determined.<ref>{{cite book|last=Knoll|first=G.F.|title=Radiation Detection and Measurement|edition=3rd|page=365|publisher=Wiley |date=1999|isbn=978-0-471-07338-3}}</ref>

The energy required to produce electron-hole-pairs is very low compared to the energy required to produce paired ions in a gas detector. Consequently, in semiconductor detectors the [[statistical variability|statistical variation]] of the pulse height is smaller and the energy resolution is higher. As the electrons travel fast, the time resolution is also very good, and is dependent upon [[rise time]].<ref>Knoll, p119</ref> Compared with [[gaseous ionization detectors]], the [[density]] of a semiconductor detector is very high, and charged particles of high energy can give off their energy in a semiconductor of relatively small dimensions.{{Citation needed|date=May 2023}}