电子束聚焦偏转系统中透镜和偏转器不对中装配误差效应的数值计算

本文讨论了透镜和偏转器在电子束系统中不对中装配造成的电子光学性质影响的数值计算问题,包括推导出不对中的透镜和偏转器在系统中的电磁场表示式,电子轨迹方程及象差积分式等。根据这些公式所编制的计算机程序已用来计算了若干个实例,从中可见不对中误差效应的数值计算对于设计和装配电子束聚焦偏转系统起到指导性的作用。

NUMERICAL COMPUTATION OF MISALIGNMENT ASSEMBLING ERROR EFFECT OF LENSES AND DEFLECTORSIN ELECTRON BEAM FOCUSING ANDDEFLECTION SYSTEMS

The misalignment assembling error effect of lenses and deflectors and its evaluation in electron beam focusing and deflection systems are discussed. First the electrostatic and magnetic field expression in electron beam systems due to the misaligned lenses and deflectors are derived. Then the formulae for evaluating the changes of the optical properties caused by the misalignment assembling errors (i.e. the additional image shifting and additional aberrations) are given by the derived field expression and the general ray equation. A set of programs based on the formulae given is developed, and some illustrative examples are also shown as the spot-diagrams. It can be reflected that the numerical computation of the misalignment assembling error effect plays important role in both designing and assembling electron beam focusing and deflection systems.