Cherenkov radiation
A ring-imaging Cherenkov (RICH) detector allows the identification of electrically charged subatomic particle types through the detection of the Cherenkov radiation emitted (as photons) by the particle in traversing a medium with refractive index formula_1 &gt; 1. The identification is achieved by measurement of the angle of emission, formula_2, of the Cherenkov radiation, which is related to the charged particle's velocity formula_3 by