Методы снижения уровня дефокусирующих составляющих в магнитных фокусирующих системах с однородным магнитным полем

Methods for decreasing the level of defocusing components in magnetic focusing systems with a uniform magnetic field

In this article, the authors consider the influence of the defocusing factors of the magnetic field on the focusing of electron beams in multipath electronic devices. The authors established the dependence of the permissible level of defocusing magnetic induction components on the linear dimensions and position of the channels. It was concluded that the smaller the channel radius and the longer the channel, the more stringent the requirements for the level of the transverse component of the magnetic induction. To improve the focusing properties of a magnetic focusing system, one should strive to reduce the average, and not the maximum level of the defocusing components along the length of the channel. Based on the known formulas for calculating the radial component of magnetic induction at a distance from an axially symmetric magnetic field, the maximum permissible level of heterogeneity of the axial component of magnetic induction is determined depending on the specified parameters of the magnetic focusing system and the device. The role and significance of random and regular factors in the formation of the level of defocusing components are determined, the necessary mathematical relationships are derived. The design of a magnetic focusing system for a multibeam device, which makes it possible to reduce the level of the defocusing component of the magnetic induction on the electron beam channels remote from the axis, is presented and theoretically justified.