Analysis of a range of symmetrical three-aperture electrostatic lenses

Author

El-Kareh, Auguste B. ; Sturans, Maris A.

Author_Institution

University of Houston, Houston, Tex.

Volume

19

Issue

10

fYear

1972

fDate

10/1/1972 12:00:00 AM

Firstpage

1075

Lastpage

1084

Abstract

The three-aperture electrostatic lens was investigated in great detail. The potential along the axis was obtained using the relaxation technique. The cardinal points and coefficients of spherical and chromatic aberration were numerically calculated from the axial potential distribution using the classical Scherzer and Glaser formulas. The results are given for a range of lenses and for a series of voltage ratios $V_{1}/V_{2}$ where V1and V2are the potentials of the inner and outer electrodes, respectively. The ratio of the aperture radii $R_{2}/R_{1}$ is varied from 0.25 to 1 in steps of 0.25. The separation of the electrodes $S/R_{1}$ is varied from 0.5 to 3 in steps of 0.5, and the thickness of the central electrode $T/R_{1}$ is varied from 0.25 to 2 in steps of 0.25. The influence of all these parameters on the cardinal points and aberration coefficients is discussed and comparison is made with published experimental and theoretical results.

Keywords

Apertures; Displays; Electrodes; Electrons; Electrostatic analysis; Geometrical optics; Lenses; Optical devices; Resistors; Voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/T-ED.1972.17552

Filename

1477023