Cherenkov detector

A Cherenkov (Čerenkov) detector is a particle detector using the mass-dependent threshold energy of Cherenkov radiation. This allows a discrimination between a lighter particle (which does radiate) and a heavier particle (which does not radiate).

It is a more advanced form of scintillation counter. A particle passing through a material at a velocity greater than that at which light can travel through the material emits light. This is similar to the production of a sonic boom when an airplane is traveling through the air faster than sound waves can move through the air. This light is emitted in a cone about the direction in which the particle is moving. The angle of the cone, $\theta_c$, is a direct measure of the particle's velocity through the formula

$\cos \theta_c = \frac{c}{nv}$,

where $c$ is the speed of light, and $n$ is the refractive index of the medium. Alternatively, if the momentum of the particle is known (from magnetic bending) the Cherenkov's information on the particle's velocity enables the mass to be deduced so that the particle can be identified.

See also

• Ring imaging Cherenkov detector
• Super-Kamiokande
• Cherenkov radiation