Accession Number : AD0286292

Title :   Studies of Primary Electron Sources.

Corporate Author : MINNESOTA UNIV MINNEAPOLIS ELECTRON TUBE RESEARCH LAB

Report Date : AUG 1962

Pagination or Media Count : 1

Abstract : An experiment in which oxygen and hydrogen were admitted to a tube containing an active-based oxide cathode is described. The admission of oxygen poisoned the cathode early in life and permanently reduced the emission by an order of magnitude. Operation at an elevated temperature and a complete reconversion to 1323 K did not change the emission. Hydrogen was admitted at low pressures and caused small changes in the emission. The problem of evaporative cooling in an oxide cathode during current drain was analyzed. Further data on the photoelectric yield and thermionic pulse emission from BaO cathodes produced by converting BaCO3 are presented. The time-temperature dependence of the photoelectric yield foll wing a life period on a cathode is discussed. Measurements of tunnel current through Al2O3-Al samples are discussed. Results of tunnel current measurements on thin film Ta-Ta2O5-metal devices are described. Measurements were made on samples having active areas with Al and also with Au overlayers. Further data are presented on the enhanced electron emission from a superconducting field emitter which occurs when the transition from superconducting to normal state is approached. (Author)

Descriptors :   *CATHODES (ELECTRON TUBES), *OXIDE CATHODES, *SUPERCONDUCTORS, *THERMIONIC EMISSION, ALKALINE EARTH OXIDES, ALUMINUM COMPOUNDS, ANODES (ELECTRON TUBES), BARIUM COMPOUNDS, ELECTRON TUBES, LIFE EXPECTANCY, OXIDES, PHOTOELECTRIC EFFECT, SEMICONDUCTORS, TANTALUM, TANTALUM COMPOUNDS, TEMPERATURE

Distribution Statement : APPROVED FOR PUBLIC RELEASE