TITLE

A new concave electrostatic lens with periodic electrode configuration

AUTHOR(S)
Nakata, Shuhei
PUB. DATE
June 1993
SOURCE
Review of Scientific Instruments;Jun93, Vol. 64 Issue 6, p1432
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
To obtain a large aperture lens with outstanding focal length homogeneity, a concave electrostatic quadrupole lens with a periodic configuration of the electrodes was developed and its performance was numerically studied. By adjusting the azimuthal angle (θ[sub c]) of the electrode to an adequate periodic function along the lens axis, the integration of the field gradient along the axis, for a period (...φdz/...dz), becomes equal to an ideal quadrupole field distribution. To verify the usefulness of the lens, the beam spot distortion of the paraxial beam, which had an initial beam diameter of 90% of the lens radius, was calculated. The results revealed that the error of the focal length inside 90% of the lens radius was only 0.012% when the lens has nine period per unit length. Also, by considering the characteristics of the modified Bessel function, a simple formula for the uniformity of the focal length was obtained, and this expression agreed well with the simulation results.
ACCESSION #
9784810

 

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics