Ring imaging Cherenkov detector

A ring imaging Cherenkov detector (RICH detector) is a particle detector that can determine the velocity, v, of a fundamental particle. This is done by an indirect measurement of the Cherenkov angle, θ_c, i.e. the angle between the emitted Cherenkov radiation and the particle path. This is related to the velocity by cosθ_c = c / nv, where c is the speed of light and n is the refractive index of the medium. The detector consists of a ring of material in which the radiation is produced. The outer radius of the ring is a mirror which reflects the radiation unto the inner radius, a radiation detector. The distance on the inner radius, r, between the original particle path and the detected radiation is related to the Cherenkov angle by r = fθ_c, where f is the focal length of the mirror. Combining this with the above relation, the velocity can be determined.

See also: Ring imaging Cherenkov detector, Cherenkov radiation, Fundamental particle, Particle detector, Physics, Cherenkov angle