电子束聚焦偏转系统中透镜加工误差效应的数值计算
NUMERICAL COMPUTATION OF PROCESSING ERROR EFFECT OF LENSES IN ELECTRON BEAM FOCUSING AND DEFLECTION SYSTEMS
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摘要: 本文讨论了由于电磁透镜中电极和极靴加工的误差(孔径椭圆度和端面倾斜)造成电子束系统电子光学性质影响的数值计算问题,包括用有限元法计算具有孔径椭圆度和端面倾斜的透镜中电磁场的分布,电子轨迹方程和像差积分式等。最后给出了用所编制的计算机程序计算的若干个加工误差效应的实例。Abstract: The numerical computation of processing error effect of lenses (i.e., the ellipticity and tilt of electrodes/pole-pieces in electron beam focusing and deflection systems) and its evaluation are discussed. First, the computation of the potential distributions of lenses with elliptical holes of tilt surfaces on electrodes/pole-pieces using the finite element method is described. Then, the formulae for evaluating the changes of the optical properties caused by the processing errors (i.e., the additional image shifting and additional aberrations) are derived. Finally, some illustrative examples of processing error effect evaluated by the computer programs developed are shown as the spot-diagrams.
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朱协卿,刘浩宁,电子科学学刊,12(1989)4,402-414.[2]西门纪业,电子和离子光学原理及像差导论,科学出版社,北京,p. 56.[3]E. Munro, Ph. D thesis, University of Cambridge, 1972, p. 123.[4]E. Munro, H. C. Chu, Optik,60(1982) 4, 371.[5]E. Munro. H. C. Chu, Optik,61 (1982)1,1.[6]H. C. Chu. E. Munro, Optik, 61(1982)2, 121.
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