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Light produced by charged particles when they pass through an optically transparent medium at speeds greater than the speed of light in that medium. For example, when electrons from a nuclear reactor travel through shielding water, they do so at a speed greater than that of light through water and they displace some electrons from the atoms in their path. This causes emission of electromagnetic radiation that appears as a weak bluish-white glow. The phenomenon is named for Pavel A. Cherenkov (1904–1990), who discovered it; he shared a 1958 Nobel Prize with Igor Y. Tamm (1895–1971) and Ilya M. Frank (1908–1990), who interpreted the effect.
This entry comes from Encyclopædia Britannica Concise. For the full entry on Cherenkov radiation, visit Britannica.com.