The Effect of Condensation on the Breakdown Strength of a Helium-Mercury Mixture,
Abstract
The effect of condensation on the DC breakdown strength of a helium-mercury mixture (helium at a reference pressure of one atmosphere with up to ten percent by weight of mercury) was calculated. The breakdown condition was determined by considering the electron current produced by ion bombardment of the cathode. The first Townsend coefficient was used as the parameter to describe breakdown. The first Townsend coefficient was computed by taking moments of the electron distribution function. The distribution function was calculated using a first order expansion in spherical harmonics of the distribution function in Boltzman's equation. The resulting equation for the distribution function was solved using integral and differential equation techniques in an iterative scheme. It was found that the presence of drops increased the breakdown strength by up to 88% over that of helium (with the Penning effect) without drops. Also, an analytical form for the contribution of drops to the first Towsend coefficient and an analytical method of estimating the increase in breakdown strength are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1971
- Accession Number
- AD0733328
Entities
People
- Daniel J. Fink
Organizations
- Massachusetts Institute of Technology