Further improvement of the high-efficiency, high-energy hydrogen-fluoride chain chemical lasers initiated by an intense electron beam

In order to further improve the output performances, the operational characteristics of the hydrogen fluoride (HF) chain chemical lasers initiated by an intense electron beam were theoretically analyzed with a new computer code including ionic reactions. Both theoretical HF laser output energy and pulsewidth were in good agreement with the experiment. Furthermore, we made an optimization of the laser gas mixtures and the electron-beam-current density in order to obtain a high efficiency within the limit of our experimental conditions. In consequence of the experiment based on the theoretical results, a maximum output energy of 5.0 kJ (268 J/l) was obtained from the low total pressure mixture (282 Torr) of F₂/H₂/SF₆/O ₂=139/58/45/42 (Torr) with a high electrical efficiency of 284% and a chemical efficiency of 20.3%. The corresponding total efficiency reached 18.9%. Moreover, aiming at the achievement of the high chemical efficiency, a maximum chemical efficiency of 29.6% was attained with a 317-Torr mixture of F ₂/H₂/SF₆/O₂=167/30/70/50 (Torr). The maximum output energy was 4.9 kJ (259 J/l), corresponding to a high total efficiency of 26.4% and an electrical efficiency of 246%.