13C-separation by a continuous discharge CO 2 laser q-switched at 10 kHz

Abstract

Compared to atmospheric pressure pulsed CO 2 (TEA) lasers, continuous-discharge CO 2 lasers can deliver photons at much lower costs. By a Q-switched version of such a laser we demonstrated by multiphoton dissociation of CHClF 2 the production of 1 g of C 2F 4 enriched to 50% 13C. This is a larger quantity of high enrichment than has been produced so far using TEA lasers. The process is already automated to a large extent. Scaling up seems feasible. These results have been achieved, although the process turned out to be much more nonlinear for our pulses (length 200 ns) than for TEA laser pulses. This difference is attributed to intensity effects, caused by direct multiphoton transitions in the excitation ladder. To avoid that selectivity breaks down, the gas has to be exchanged more than once per pulse. The required speed is much less, if ~250 mbar of Ar are added to the working gas.