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Proceedings Paper

Aberration analysis of wide-angle deflectors and lenses by direct ray-tracing and comparison with conventional aberration theories
Author(s): Eric Munro; Xieqing Zhu; John A. Rouse; Haoning Liu
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Paper Abstract

This paper describes numerical techniques for computing aberrations in focusing and deflection systems for charged particle beams, and electron sources and mirrors, by direct ray- tracing of electron or ion trajectories. For such computations to be meaningful and reliable, high accuracy in the computed potential distribution and field components is essential. Suitable methods for potential and field computation in 2D and 3D are outlined, including finite difference and second-order finite element methods, Biot-Savart law and charge density method. A method for direct ray-tracing through these fields is then summarized, using a Runge-Kutta formula. To compare the results of direct ray-tracing with conventional aberration theories, techniques for computing third and fifth-order aberrations using axial field functions and aberration integrals are described. The techniques are illustrated by several examples, including: analysis of spherical and chromatic aberration of an electrostatic lens by direct ray-tracing; analysis of a magnetic probe-forming SEM lens with wide-angle magnetic deflection, with either post-lens or pre-lens deflection; analysis of quadrupole lenses by direct ray-tracing and multipole aberration theory; aberration analysis of an electron mirror by direct ray-tracing; and analysis of the aberration of electron and ion sources.

Paper Details

Date Published: 25 September 1995
PDF: 12 pages
Proc. SPIE 2522, Electron-Beam Sources and Charged-Particle Optics, (25 September 1995); doi: 10.1117/12.221611
Show Author Affiliations
Eric Munro, Munro's Electron Beam Software Ltd. (United Kingdom)
Xieqing Zhu, Munro's Electron Beam Software Ltd. (United Kingdom)
John A. Rouse, Munro's Electron Beam Software Ltd. (United Kingdom)
Haoning Liu, Munro's Electron Beam Software Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 2522:
Electron-Beam Sources and Charged-Particle Optics
Eric Munro; Henry P. Freund, Editor(s)

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