Other Types of Detectors
. Many other types of interactions between matter and elementary particles are used in detectors. Thus in semiconductor detectors, electron-hole pairs that elementary particles produce in a semiconductor junction momentarily increase the electric conduction across the junction. The Cherenkov detector, on the other hand, makes use of the effect discovered by the Russian physicist Pavel Alekseyevich Cherenkov in 1934: A particle emits light when it passes through a nonconducting medium at a velocity higher than the velocity of light in that medium (the velocity of light in glass, for example, is lower than the velocity of light in vacuum). In Cherenkov detectors, materials such as glass, plastic, water, or carbon dioxide serve as the medium in which the light flashes are produced. As in scintillation counters, the light flashes are detected with photomultiplier tubes. Neutral particles such as neutrons or neutrinos can be detected by nuclear reactions that occur when they collide with n