Some characteristics of a magnetically focused electron beam

Abstract

The detailed behavior of a solid cylindrical electron beam focused by a uniform magnetic field (Brillouin flow) has been studied experimentally. These studies include the influence of the optics of the electron gun on the beam-focusing characteristics, the effects of transverse "thermal" velocities, the change in the internal beam dynamics with increasing values of magnetic focusing field, etc. A simple model of the beam is used to explain certain of the observed characteristics. It is found that an optically good electron gun will produce a focused beam which closely resembles the theoretical Brillouin-flow model. A brief analysis of the electron motion in a magnetically focused beam is given in the Appendix. © 1959 The American Institute of Physics.