Space‐charge aberrations in the photoelectron microscope
作者:
G. A. Massey,
M. D. Jones,
B. P. Plummer,
期刊:
Journal of Applied Physics
(AIP Available online 1981)
卷期:
Volume 52,
issue 6
页码: 3780-3786
ISSN:0021-8979
年代: 1981
DOI:10.1063/1.329216
出版商: AIP
数据来源: AIP
摘要:
The contributions of space charge to chromatic and trajectory aberrations of accelerating electrons in a laser‐illuminated photoelectron microscope are calculated. Average and fluctuating components of the electrostatic forces on the particles are considered spearately. The average forces produce a magnification change but no chromatic spread. Fluctuating effects include relaxation of potential to kinetic energy in a beam obeying Poisson emission statistics, and transverse‐to‐longitudinal velocity relaxation by multiple scattering. The potential energy relaxation is treated in a new way by modifying the Poisson distribution with position along the beam axis. The field fluctuations produce both chromatic and trajectory spreading effects, the latter being much larger at high currents. The resolution limit is about 500 A˚ for 30‐kV electrons in a beam of 1‐A/cm2current density.
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