Transition Radiation - History

History

Transition Radiation was theoretically discovered by Ginzburg and Frank in 1945. In their work they showed appearance of Transition Radiation when charged particle perpendicularly passed boundary between two homogeneous media. The frequency of radiation was mainly in the range of optical frequencies, if considering the part or radiation that was emitted in the backwards direction related to the movement of particle. Intensity of radiation was logarithmically proportional to the Lorentz factor of the particle. Which meant that measurement of intensity of the TR was providing new ways of defining Lorentz factor of the relativistic particles. But the energy of radiation was very small which made it difficult to measure.

In 1959 Garibian theoretically showed that energy loses of the ultrarelativistic particle, when emitting TR while passing the boundary between media and vacuum were directly proportional to the Lorenz factor of the particle. Additional research pointed out that the reason for that dependency was that the radiation emitted in the direction of movement of particle included also X-ray frequencies.

Theoretical discovery of X-Ray Transition Radiation, which was directly proportional to the Lorenz factor, made possible further use of TR in the physics of high energies. Thus, from 1959 intensive theoretical and experimental research of TR, and X-ray TR in particular began.