Accession Number : AD0660289

Title :   STUDIES OF VACUUM BREAKDOWN BETWEEN MICRON-SIZED AREAS.

Descriptive Note : Technical rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Hieslmair,Hans ; Guetzlaff,Harry T. ; Long,Martin L. ; Mallery,Barbara A. ; Fitzpatrick,William P.

Report Date : SEP 1967

Pagination or Media Count : 19

Abstract : Vacuum breakdown between broad-area electrodes is initiated and occurs in localized areas of the electrodes. In the present report a new method of investigating such localized areas with a modified Muller Microscope is described and results are discussed. The method consists of scanning a metal surface with a small area electrode (anode) at a distance of a few microns, while a voltage of 1 to 3 kilovolts is applied. When scanning the surface, the distance between the electrodes is so adjusted that the current and voltage remain constant. In this manner a plot of the cathode surface is obtained, and micron-sized inhomogeneities can be detected. In contrast to microscopic or electron microscopic techniques, this method allows the observation of changes of the emission characteristics of a surface while high electric fields are applied. The experimental results indicate that changes of the electrodes occur even at current levels of 10 to the minus 10th power amperes when the surface is scanned for the first time. Apparent inhomogeneities of the cathode surface can be created or destroyed by current pulses of 0.1 microampere. Fowler-Nordheim plots give further information about these changes which eventually initiate vacuum breakdown. (Author)

Descriptors :   (*FIELD EMISSION, ELECTRODES), VACUUM, SCANNING, SURFACES, LEAKAGE(ELECTRICAL), COPPER, TUNGSTEN

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE