High-energy nuclei with a charge greater than or equal to six are capable of producing Cerenkov light. The light observed is frequently attributed to a shock wave phenomenon and has been thought of as an optical analog of the sonic boom; however, this is not entirely correct. What actually happens is that a fast-moving charged particle moving through a dielectric medium causes local, non-isotropic polarizations in the atoms of the dielectric. These atoms return to normal states by emitting light. If the velocity of the particle is less than the velocity of light in the medium, the light is destroyed by destructive interference. If the velocity of the particle is greater than the velocity of light in the medium, the light remains due to constructive interference.
The phenomenon was discovered by Mallet in 1926 and studied by Cerenkov from 1934 to 1938. Cerenkov proved that it was not a fluorescence effect and found that the light was partially polarized. A correct theoretical explanation for Cerenkov radiation was first given by Frank and Tamm in 1937.
Cerenkov radiation is used in a Cerenkov counter or detector of energetic particles.
Related category PARTICLE PHYSICS
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