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Updated: Aug 3, 2025

Sample Preparation and Experimental Design for In Situ Multi-Beam Transmission Electron Microscopy Irradiation Experiments
Published on: June 27, 2022
In multi electron beam systems, "Neighbours Matter"
A Mohammadi-Gheidari1, E R Kieft2, X Guo3
1Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, the Netherlands; Thermo-Fisher Scientific, De Schakel 2, 5651 GG Eindhoven, the Netherlands.
Abstract:
In the Multi beam source (MBS) of our Multi Beam Scanning Electron Microscope (MBSEM), an aperture lens array (ALA) splits the emission cone of the Schottky field emitter into multiple beamlets. When the apertures in the ALA are close to each other, the ALA can introduce aberrations to these beamlets through the electrostatic interaction of neighbouring apertures with each aperture's lens field. When the apertures are arranged in a square grid pattern, the aberration causes fourfold astigmatism. The effect on the beam spot is analyzed through a combination of 3D simulations and experimental validation. To counterbalance the fourfold astigmatism, a correction scheme is proposed in which a slightly non-round profile is applied to the aperture lenses.
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