4 – ČERENKOV RADIATION

Publisher Summary This chapter discusses C˘erenkov radiation. Various substances, including solutions of mineral salts, emit a feeble light under the influence of radiations from radioactive substances. It was discovered in the course of time that this was, in general, fluorescent light that behaved in much the same way as did that emitted from certain substances under irradiation by ultraviolet light. While investigating the luminescence of solutions of uranyl salts under the influence of γ  -rays, C˘erenkov discovered in 1934 that a very weak radiation was visible even from pure liquids. The C˘erenkov detector has proved to be a very useful tool in nuclear and cosmic-ray physics, for it has the merits of great speed, high efficiency, and marked directional properties. It is also simple to construct and does not in general require rare materials. Its applications are, however, somewhat restricted by the very nature of the phenomenon of the C˘erenkov radiation, though it is likely that its usage will increase in the near future as ever higher and higher energy particles become available from the new types of accelerating machines.