Accession Number : ADA187700

Title :   High-Current Density, High-Brightness Electron Beams from Large-Area Lanthanum Hexaboride Cathodes.

Descriptive Note : Memorandum rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Loschialpo, P ; Kapetanakos, C A

PDF Url : ADA187700

Report Date : 13 Dec 1987

Pagination or Media Count : 33

Abstract : Large (approx. 5 cm) diameter lanthanum hexaboride (LaB6) cathodes operated at 10 kV have produced 1-5 micro electron pulses with current density between 10 and 20 A/sq. cm. Normalized beam brightness, has been consistently measured. To obtain this high current density, the LaB6 cathodes have been heated to temperatures between approx 1600 - 1800 C. Very uniform temperature profiles are obtained by applying a carefully tailored electron bombardment heating power distribution. These measurements have been made between pressure .000001 to .00001 Torr, i.e., under much less demanding vacuum conditions than that required by conventional dispenser type cathodes. Keywords: Beam quality, Cathodes, Brightness.

Descriptors :   *CATHODES(ELECTRON TUBES), *ELECTRON BEAMS, BORIDES, BRIGHTNESS, CATHODES, CURRENT DENSITY, ELECTRON EMISSION, HEAT, HIGH DENSITY, HIGH POWER, LANTHANUM COMPOUNDS, TEMPERATURE, VACUUM, GYROTRONS, COHERENT OPTICAL RADIATION, OSMIUM, THERMIONIC EMISSION, THERMAL ANALYSIS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE