Publication Date:
2014-12-19
Description:
Publication date: January 2015 Source: Ultramicroscopy, Volume 148 Author(s): Jack C. Straton A converging electron mirror can be used to compensate for spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a diode (two-electrode) electrostatic mirror including the next term beyond the known hyperbolic shape. The latter is a solution of the Laplace equation to second order in the variables perpendicular to and along the mirror׳s radius ( z 2 − r 2 / 2 ) to which we add a quartic term ( k λ z 4 ). The analytical solution is found in terms of Jacobi cosine-amplitude functions. We find that a mirror less concave than the hyperbolic profile is more sensitive to changes in mirror voltages and the contrary holds for the mirror more concave than the hyperbolic profile.
Print ISSN:
0304-3991
Topics:
Electrical Engineering, Measurement and Control Technology
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Natural Sciences in General
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Physics
