Date of Award:
5-1996
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Physics
Committee Chair(s)
John R. Dennison
Committee
John R. Dennison
Committee
W. John Raitt
Committee
Jan J. Sojka
Abstract
Secondary electron emission (SEE) and incident-particle backscattering are important processes accompanying the impact of energetic electrons and ions on surfaces. The phenomena play a key role in the buildup of electrical charge on spacecraft surfaces. and are therefore of particular interest to scientists attempting to model spacecraft charging. In response to a demonstrated need for data, techniques for determining total secondary electron (SE) and backscatter (BS) yields S and n, and associated scattering-angle-resolved, scattering-energy-resolved, and simultaneous angle-energy-resolved yields have been developed. Further, an apparatus capable of making the necessary measurements for experimental determination of these quantities-for conducting materials in an ultra-high vacuum environment-has been designed, constructed, and partially tested. The apparatus is found to be in working order, though in need of fine-tuning, and the measurement technique successful.
Investigations using a 1-3 keV beam of monoenergetic electrons normally incident on bulk Al have been undertaken with the new apparatus. Electron-stimulated desorption of surface contaminants has been observed, as has been beam-induced carbon deposition, and an empirical model describing the resulting dynamic evolution of S is presented. Total S and n values obtained in the present investigation are found to be in qualitative agreement with the results of previously reported investigations, though quantitative disagreement of S-values is substantial. Specifically, evidence is presented suggesting that previously reported SE yields for clean Al under electron bombardment (in the 1-3 ke V energy range) are in error by as much as 30 %.
Checksum
d40a98f0290808fdbf52dbeeb1d3f82c
Recommended Citation
Davies, Robert, "An Instrument for Experimental Secondary Electron Emission Investigations, with Application to the Spacecraft Charging Problem" (1996). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 1697.
https://digitalcommons.usu.edu/etd/1697
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