Analysis and calculation of third- and fifth-order aberrations in combined bell-shaped electromagnetic lens - a new theoretical model in electron optics

摘要

The author has developed canonical aberration theory, and has performed a generalized integration transformation on eikonals. Electron optical aberrations have first been derived for up to the ninth-order approximation in rotationally symmetric magnetic and electrostatic lenses. In the present paper, based on above-mentioned theoretical results, analytical formulas for Gaussian trajectory, third- and fifth-order geometric aberration coefficients have first been derived in a so-called combined bell-shaped electromagnetic lens-a new theoretical model first proposed in electron optics. We have shown that the range of the lens-strength parameter for a combined bell-shaped electromagnetic lens. It is to be expected that this theoretical research may be useful for estimating variations and effects of higher-order aberrations in rotationally symmetric combined electromagnetic lenses. [References: 11]