DocumentCode
761050
Title
Degradation factors of a coated impregnated cathode
Author
Mita, Nagahisa
Author_Institution
NTT, Kanagawa, Japan
Volume
39
Issue
9
fYear
1992
fDate
9/1/1992 12:00:00 AM
Firstpage
2172
Lastpage
2175
Abstract
An M-type cathode has two life-limiting factors: the reduction of impregnants and the degradation of surface coating. The optimum operating temperature and lifetime against the cathode current density are derived for the former. The quantitative temperature dependence on the lifetime of the surface coating is determined by comparing the measured results and theoretical calculations. A comparison of these factors reveals that the lifetime of a coated impregnated cathode is determined by the reduction of impregnants when the cathode is operated at the optimum temperature and with a current density less than 24 A/cm 2
Keywords
thermionic cathodes; travelling-wave-tubes; M-type cathode; coated impregnated cathode; current density; degradation factors; life-limiting factors; lifetime; operating temperature; optimum temperature; reduction of impregnants; surface coating degradation; temperature dependence; Atomic measurements; Barium; Cathodes; Coatings; Current density; Degradation; Frequency; Sputtering; Temperature dependence; Tungsten;
fLanguage
English
Journal_Title
Electron Devices, IEEE Transactions on
Publisher
ieee
ISSN
0018-9383
Type
jour
DOI
10.1109/16.155889
Filename
155889
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