An X-ray preionised self sustained discharge HF/DF laser

We report the design and characterisation of a flash X-ray preionised, transversely excited HF/DF laser with energy outputs at the joule level. The laser used a H₂/D₂: SF₆ mixture at a pressure of around 120 Torr. X-ray photon fluxes and ionisation rates in the laser gas are presented and the laser dependence on these examined. It is shown that X-ray preionisation can be effective and it is estimated that the laser should operate satisfactorily with as little as 5% of the total stored electrical energy in the preionisation circuit. The laser performance is comparable to that of a UV preionised device with similar operating parameters.