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Partial differential cross-sections for electron production by 20 to 120 keV proton impact on argon
Abstract
Energy-analyzed secondary electrons from 20-120 keV H$\sp+$ + Ar collisions were detected in coincidence with recoil ions of various charge states. The recoil ion charge states were determined by time-of-flight measurements. The resulting time spectra were processed to obtain the electron production cross section as a function of electron energy and recoil ion charge state. In order to obtain a usable coincidence count rate with a reasonable energy resolution, a new type of electrostatic analyzer was developed and built which has a large ($\sim$1.45$\pi$ steradian) solid angle acceptance. This analyzer, which is similar to apparatus used in low energy electron diffraction (LEED) experiments, has a low-pass filter consisting of a hemispherical electrode with a concentric grid and a high-pass filter consisting of two concentric hemispherical grids. Aspects of the design of the analyzer and the testing procedure are described. A statistical model was used for the theoretical calculation of the partial cross sections, and compared with the experimental data. The theory qualitatively agrees with the data. The experimental data show that the average charge state of the recoil ions increases with increasing electron energy. For a given electron energy, the average charge state of the recoil ions is a maximum at a projectile energy of 60 keV.
Subject Area
Atoms & subatomic particles
Recommended Citation
Chung, Yang-Soo, "Partial differential cross-sections for electron production by 20 to 120 keV proton impact on argon" (1993). ETD collection for University of Nebraska-Lincoln. AAI9402390.
https://digitalcommons.unl.edu/dissertations/AAI9402390