CO2 laser tritium isotope separation: Collisional effects in multiphoton dissociation of trifluoromethane

Abstract

Multiphoton dissociation of ppm level CTF3 in CHF3 is reported. The effect of buffer gas pressure on the specific dissociation rates and the isotopic selectivity is investigated. Pulse energy dependence of the dissociation rates is converted to the intrinsic relation between the fractional conversion per pulse and the fluence by means of the new deconvolution technique. By addition of 100 Torr argon, the critical fluence of CTF3 was decreased from 136 to 34 J/cm2, while the intrinsic selectivity was increased from 34 to 580. In the absence of buffer gas argon, the fractional conversion per pulse exhibits two different pressure dependences. Unlike in the case below 15 Torr, the system shows strong pressure dependence and loss of the isotopic selectivity above 15 Torr. Possible application to the tritium removal process is also discussed.