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Title: Experimental Test Of Whether Electrostatically Charged Micro-organisms And Their Spores Contribute To The Onset Of Arcs Across Vacuum Gaps

Recently it was proposed [L.R. Grisham, A. vonHalle, A.F. Carpe, Guy Rossi, K.R. Gilton, E.D. McBride, E.P. Gilson, A. Stepanov, T.N. Stevenson, Physics of Plasma 19 023107 (2012)] that one of the initiators of vacuum voltage breakdown between condu cting electrodes might be micro-organisms and their spores, previously deposited during exposure to air, which tnen become electrostatically charged when an electric potential is applied across the vacuum gap. The note describes a simple experiment to compare the number of voltage-conditioning pulses required to reach the nominal maxium operating voltage across a gap between two metallic conductors in a vacuum, comparing cases in which biological cleaning was done just prior to pump-down with cases where this was not done, with each preceded by exposure to ambient air for three days. Based upon these results, it does not appear that air-deposited microbes and their spores constitute a major pathway for arc initiation, at least for exposure periods of a few days, and for vacuum gaps of a few millimeters, in the regime where voltage holding is usually observed to vary linearly with gap distance
Authors:
;
Publication Date:
OSTI Identifier:
1129032
Report Number(s):
PPPL-4991
DOE Contract Number:
DE-ACO2-09CH11466
Resource Type:
Technical Report
Resource Relation:
Related Information: Published in Phys. Plasmas 20 , 124504 (2013)
Publisher:
Phys. Plasmas 20 , 124504 (2013)
Research Org:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY Micro-organisms