Effect of SF₆ fluorine donor on the multikilojoule HF chemical laser initiated longitudinally by intense electron beams

The effects of fluorine donor additives and initiation level on the HF laser output characteristics in a strong and short pulse initiation regime are experimentally and theoretically investigated. Typical parameters of the circular e beam used in the experiment are 2 MV, 60 kA, 65 ns FWHM, and 10 cm in diameter, and the e beam is injected longitudinally. The addition of SF ₆ gas to a mixture of F₂/O₂/H₂ is found to increase not only the specific laser energy but also the electrical laser efficiency. The maximum laser energy obtained from the low-pressure mixture of F₂/SF₆/O₂/H₂=200/84/60/45 (Torr) is 4.4 kJ in a 70 ns FWHM with an electrical laser efficiency of 203% and a chemical laser efficiency of 18.6%. Based on the experimental results, the scaling of the HF laser was established in terms of specific HF laser energy and electrical laser efficiency.