부산대학교 도서관

A 2-liter subsonic-flow HF chemical laser has been constructed to evaluate the performance of the H2-F2-He system at high pressures and to investigate the problems associated with repetitive pulsing. While operating in the single-pulse mode at F2 dissociation levels of 0.1 to 0.2 percent, output energies of 8 to 12 J/1-atm have been obtained at 120 to 250 Torr with electrical efficiencies of 80 to 120 percent. Operation at pressure in excess of 500 Torr was also obtained with reduced electrical efficiency. Comparisons of experiment with theory show significant discrepancies in laser energies and pulse lengths at low dissociation levels. The indications are that deactivation of the higher vibrational states of HF may be considerably faster than is currently assumed. Studies of combustion phenomena in representative laser mixtures indicate that the equilibrium flame velocities are <25 m/sec and that the propagation of detonation waves may be stopped by several layers of fine mesh screen. Studies of the medium quality show no significant density disturbances for times <5 micro sec after initiation, indicating that operation with short laser pulses will produce good beam quality. Measurements of the laser cavity clearing time indicate that the device could be pulsed at rates in excess of 100 Hz with only minor modifications. (Author)