The Spatial Asymmetry of Cerenkov Radiation as a Function of Electron Energy

Abstract

The properties of the radiation discovered in 1934 by P. A. Cerenkov when high speed electrons traverse transparent media has been studied as a function of the energy of the bombarding particle. It is found that the direction of emission of the radiation for mica over the range from 240 to 815 kv is given by the relation proposed by Frank and Tamm, where $cos\ensuremath{\theta}=\frac{1}{\ensuremath{\beta}n}$, $\ensuremath{\theta}$ being the angle of progression of the radiation with the electron beam and $n$, the index of refraction of the mica used as the target. In this range $\ensuremath{\beta}$ changes markedly, providing a significant test of this relation as a function of the energy of the bombarding particle. The experiments were carried out with the use of a transformer-rectifier source of potential and an electron tube giving a well-collimated beam of electrons.