Accession Number:

AD0248947

Title:

RESEARCH INVESTIGATION OF CATHODE EMISSIVE MATERIALS

Descriptive Note:

Corporate Author:

FRANKLIN INST NEWARK DE BARTOL RESEARCH FOUNDATION

Personal Author(s):

Report Date:

1960-10-15

Pagination or Media Count:

1.0

Abstract:

Data regarding the evaporation rate of a thorium monolayer as a function of coverage and temperature taken at Bartol and from other sources have been reduced to absolute values and are plotted. Evaporation rates from a thorium monolayer become excessive when temperatures which would over yield 100 ampsq cm are approached at 10 ampsq cm evaporation may be tolerable for certain applications. Studies were continued regarding comparison of thermionic effects of a thorium monolayer on polycrystal and single crystal tungsten. The single crystal plane currently being studied is an 832 orientation. An apparatus for growing single grain tungsten ribbons was completed and is in successful operation. Formation of the more oblique orientations is much more probable than that of 100, 110, or 111 planes. Attempts will be made to grow single grain specimens of other materials. A study of the thermionic properties of one specimen of ZrCO.80.UCO.20 was made. Contrary to a previous report from another laboratory, the Richardson A constant was found to have a normal value. Life tests on thorium impregnated tungsten matrix cathodes show that operating lifetimes of 15000 hours or greater can be expected at the 1.0 ampsq cm and 2.3 ampsq cm level. A watercooled diode has shown that, as expected, an emission of 10 ampsq cm is obtainable at 1750 degrees C brightness. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE