New Electronic-Transition Laser Systems. Part I. Electron Pumped Systems

Abstract : Considerable progress in understanding the kinetic processes involved in electron-pumped rare gas-halogen mixtures, particularly Ar/I2, is reported. This gas system has great promise as a scalable, high-power laser medium capable of being pumped by electron beam, e-beam-sustained discharge, or nuclear fission fragments. The kinetic model involves the production of excited rare gas, followed by two very fast neutral energy transfer steps. The selective energy flow is simply represented as Ar* to I* to I2* followed by collisional relaxation of the I2* to a single state radiating the 342.5 nm band with high fluorescence yield. We have made extensive experimental measurements testing this model and measuring the relevant rate coefficients and cross-sections. Kinetic steps involving halogen ions cannot be completely ruled out, but the results given here argue against their importance. Sustained discharge pumping is discussed briefly and a projected overall efficiency of approximately 20% is predicted.