Dielectric breakdown threshold in CF3H and in CF3H/CF3T mixtures using pulsed infrared radiation

摘要

Abstract: e dependence of threshold fluences for dielectric breakdown of pure CF$-3$/H and CF$-3$/H/CF$-3$/T mixtures has been studied using 10.6 $mu@m pulses from a TEA CO$-2$/ laser. Breakdown thresholds are well above the working fluences required for laser isotope separation of trifluoromethane, allowing the use of tight focused geometries without producing nonselective processes. Analysis of the experimental results suggests that breakdown occurs as a result of a cascade process, and that recombination losses are more important than electron diffusion. In the pressure range studied, the threshold in presence of CF$- 3$/T was lower than the corresponding value in pure CF$-3$/H, as a consequence of the preionization induced by the $beta decay.!19