TEMGYM Advanced - NanoMi lens characterisation

David Landers; Ian Clancy; Rafal E Dunin-Borkowski; Dieter Weber; Andrew A Stewart

doi:10.1016/j.micron.2023.103450

TEMGYM Advanced - NanoMi lens characterisation

Micron. 2023 Jun:169:103450. doi: 10.1016/j.micron.2023.103450. Epub 2023 Mar 27.

Authors

David Landers¹, Ian Clancy¹, Rafal E Dunin-Borkowski², Dieter Weber², Andrew A Stewart³

Affiliations

¹ Department of Physics, University of Limerick, Limerick, Munster, V94 T9PX, Ireland.
² Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany.
³ Department of Chemistry, University College London, 20 Gordon St, London WC1H 0AJ, United Kingdom. Electronic address: andy.stewart@ucl.ac.uk.

PMID: 37030084
DOI: 10.1016/j.micron.2023.103450

Abstract

A complete analysis including finite element method (FEM) calculation, focal length properties, and thirdorder geometric aberrations of the open-source electrostatic lens from the NanoMi project is presented. The analysis is carried out by the software TEMGYM Advanced, a free package developed to carry out ray-tracing and lens characterisation in Python. Previously TEMGYM Advanced has shown how to analyse the aberrations of analytical lens fields; this paper expands upon this work to demonstrate how to apply a suitable fitting method to discrete lens fields obtained via FEM methods so that the aberrations of real lens designs can be calculated. Each software platform used in this paper is freely available in the community and creates a free and viable alternative to commercial lens design packages.

Keywords: Aberration integral; Differential algebra; Finite element method; NanoMi; Parallelisation; Ray tracing.