Dielectric properties for SF6and SF6mixtures predicted from basic data
| Autor: | L. E. Kline, P. J. Chantry, D. K. Davies, C. L. Chen |
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| Rok vydání: | 1979 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 50:6789-6796 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.325814 |
| Popis: | We have calculated α and η, the ionization and attachment coefficients, and (E/N) *, the limiting breakdown electric‐field–to–gas‐density ratio, in SF6 and SF6 mixtures by numerically solving the Boltzmann equation for the electron energy distribution. The calculations require a knowledge of several electron collision cross sections. Published momentum transfer and ionization cross sections for SF6 were used. We measured various attachment cross sections for SF6 using electron‐beam techniques with mass spectrometric ion detection. We determined a total cross section for electronic excitation of SF6 by comparing the predicted values of α, η, and (E/N) * with our measured values obtained from spatial current growth experiments in SF6 in uniform fields over an extended range of E/N. With this self‐consistent set of SF6 cross sections, together with published He and N2 cross sections, it was then possible to predict the dielectric properties of SF6‐He and SF6‐N2 mixtures. Published experimental values of α for the SF6‐He mixtures lie between the values of α calculated with and without ionization of SF6 by excited He atoms. Published experimental values of (E/N) * agree with our calculations to within 5% in both the SF6‐He and the SF6‐N2 mixtures. |
| Databáze: | OpenAIRE |
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