DocumentCode :
891110
Title :
Synchrotron radiation studies for thermionic cathode research
Author :
Shih, Arnold ; Mueller, Donald R. ; Hemstreet, Louis A.
Author_Institution :
US Naval Res. Lab., Washington, DC, USA
Volume :
36
Issue :
1
fYear :
1989
fDate :
1/1/1989 12:00:00 AM
Firstpage :
194
Lastpage :
200
Abstract :
An approach to thermionic cathode research is described that combines surface-extended X-ray absorption fine structure (SEXAFS) and ultraviolet photoemission spectroscopy (UPS) measurements with theoretical calculations based on the full-potential linearized augmented plane wave (FLAPW) method. The physics and chemistry of the Ba and O layer present on the surface of a dispenser cathode and the relation of its properties to cathode performance are of interest. SEXAFS determines the surface geometry associated with the overlayer and UPS the electronic properties of the Ba-O covered surface. Through the correlation of the surface geometry with the surface electronic properties via FLAPW calculations, some of the essential issues that underline the performance of dispenser cathodes are identified. Some results obtained during the initial stage of this research are presented. In particular, the results indicate that the standing-up (or vertical) geometry is unlikely for Ba-O adsorption on tungsten surfaces
Keywords :
barium compounds; synchrotron radiation; thermionic cathodes; tungsten; Ba-O covered surface; BaO-W; FLAPW; SEXAFS; UPS; W surfaces; cathode performance; chemistry; dispenser cathodes; electronic properties; full-potential linearized augmented plane wave; physics; surface geometry; surface-extended X-ray absorption fine structure; synchrotron radiation studies; theoretical calculations; thermionic cathode research; ultraviolet photoemission spectroscopy; Cathodes; Chemistry; Electromagnetic wave absorption; Geometry; Photoelectricity; Physics; Spectroscopy; Surface waves; Synchrotron radiation; Uninterruptible power systems;
fLanguage :
English
Journal_Title :
Electron Devices, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9383
Type :
jour
DOI :
10.1109/16.21205
Filename :
21205
Link To Document :
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