METHOD FOR DETERMINING ABERRATION COEFFICIENT IN ABERRATION FUNCTION OF PARTICLE-OPTICAL LENS

摘要

PROBLEM TO BE SOLVED: To provide a method improved in accuracy as compared with a known method because a particle-optical lens of particle-optical apparatus, such as an objective lens, suffers from aberrations; as is already known since decades, Ronchi tests can be used to determine these aberrations of particle-optical lenses; such methods depend on determination of a secondary derived function of an aberration function based on local expansion, for instance, in one or a set of Ronchi tests; a mathematical solution method of these methods is enabled only when unboundedly slightly shifted among the Ronchi tests by depending on the secondary derived function; this means, for instance, that space quantization noise of a camera for recording the Ronchi tests causes a serious error; and these contradictory requirements restrict accuracy, that is, usability of the existing method.;SOLUTION: A set of algorithms for improving a method for quantifying a lens aberration coefficient is explained by using a set of Ronchi tests.;COPYRIGHT: (C)2007,JPO&INPIT