NUMERICAL-ANALYSIS OF HIGHER-ORDER GEOMETRIC ABERRATIONS FOR A 2-TUBE ELECTROSTATIC LENS

Based on the electron optical canonical aberration theory, up to the fifth-order geometric aberrations have been analyzed for an equal diameter two-tube electrostatic lens with the gap of 0.1 diameter and accelerating voltage ratio ranging from 5 to 40. The precisions are controlled rigorously at every step. For the computational results presented the computed first- and third-order electron optical properties agree with the accurate values published in the literature of about 0.2%, and thus the fifth-order aberration is believed to be acquired in a precision of about 1%. The contributions of third- and fifth-order aberrations to the total aberration with respect to the filling factor or the accelerating voltage ratio have been first calculated numerically in the above-mentioned electrostatic lens. The method of accurate numerical differentiation of an analytical or a digital function up to the sixth order would be expected to make a contribution to the development of computational electron optics.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1993MF84000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, AppliedSCI(E)2ARTICLE105946-59507