Advanced-laser development for isotope separation

To address a number of the issues associated with lasers appropriate for both atomic vapor and molecular laser enrichment schemes, pertinent technologies on two test devices were developed. These were a high pulse rate, 100 watt excimer laser named Mistral, and a 20 watt copper-vapor laser (CVL). Mistral is a closed-loop, 100 W, kilohertz rare gas halide laser system. The first half of the Mistral effort dealt with the study of gas flow and acoustic effects in high PRF rare gas halide lasers. In burst mode operation, 1250 Hz operation was demonstrated, the effects on flow quality of acoustic dampers were measured, and gas clearing factors of 2.5 at 1 kHz were demonstrated. The second half of the Mistral program dealt with extending the run time capability of the laser. This effort culminated with the continuous operation of Mistral for almost eight hours at 500 ppS, producing over 50 mJ/pulse at 308 nm on a single fill of Xecl gas mixture. The effectiveness of using magnetic pulse compression in the modulator circuit of a copper-vapor laser (CVL) was also verified. The magnetic switching/pulse compression scheme as used on both the CVL and Mistral greatly extends thyratron lifetime.