Influence of aging effect on behavior of field emission sites in a broad-area vacuum gap

• Published in: Electrical engineering in Japan Vol. 136; no. 3; pp. 10 - 18
• Main Authors: Takahashi, Eiji, Ebe, Akinori, Ogata, Kiyoshi, Komuro, Shigehiro, Mitsui, Hideo, Sone, Mototaka
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.08.2001
• Subjects: aging; F-N plot; field emission; insulation breakdown in vacuum; surface treatment
• ISSN: 0424-7760; 1520-6416
• DOI: 10.1002/eej.1060

In order to discuss the characteristics of field emission sites, an aging effect on field emission current was measured in terms of cathodes subjected to two different surface treatments: mechanical polishing and thin film formation. A field was applied to the test cathodes up to an emission current of 10–11A. Such measurement was repeated 50 times. It was found that the field emission current decreased with increasing number of test runs, and the amount of such degradation was larger for the case of mechanical polishing than for thin film formation. The field enhancement factor β evaluated by F–N plot was kept constant with increasing test runs for the mechanical polishing, while β increased with increasing test runs for the thin film formation. It was estimated by means of emission site observation that the emission sites on the mechanically polished cathode were related to the adsorption gases or weakly attached foreign particles, while the emission sites on the thin film formation cathode were related to the metallic whiskers. The characteristics of emission sites could be controlled by the surface treatment, especially by the thin film formation. © 2001 Scripta Technica, Electr Eng Jpn, 136(3): 10–18, 2001