Cherenkov Radiation

Abstract

When a charged particle passes through an optically transparent medium with a velocity greater than the phase velocity of light in that medium, it emits prompt photons, called Cherenkov radiation, at a characteristic polar angle that depends on the particle velocity. Cherenkov counters are particle detectors that make use of this radiation. Uses include prompt particle counting, the detection of fast particles, the measurement of particle masses, and the tracking or localization of events in very large, natural radiators such as the atmosphere, or natural ice fields, like those at the South Pole in Antarctica. Cherenkov counters are used in a number of different fields, including high energy and nuclear physics detectors at particle accelerators, in nuclear reactors, cosmic ray detectors, particle astrophysics detectors, and neutrino astronomy, and in biomedicine for labeling certain biological molecules.

This chapter begins with a brief history of the Cherenkov effect. It then describes some salient features of the radiation that leads to its unique value in particle detection. Several different classes of Cherenkov detectors will be described, along with the technology needed to build them. The chapter will conclude with a review of a number of different Cherenkov counters, including some historically important counters, more recent devices now in operations, and devices that remain under research and development that make use of innovative technologies.