Investigation of a flashlamp-initiated large-volume chemical $H_2-F_2$ laser

An investigation was made of the potentialities of an $H_2-F_2$ laser initiated by IFP-20000 flashlamps. The active volume was $\thicksim7,3$ liter and the diameter was $\thicksim14$ cm. The physics of lasing was investigated by determining the initial concentration of fluorine atoms $[F]_0$ from the absorption of ultraviolet radiation by metastable $FO_2$ radicals. The experimentally determined value of $[F]_0$ was used to find the laser efficiency $\eta_\Phi$ relative to the energy deposited in the working mixture. The experimental value $\eta_\Phi=5500$ procent was much greater than all the reported values of $\eta_\Phi$ for $H_2-F_2$ lasers with any type of initiation. The technical efficiency was 30 procent for an $H_2:F_2:O_2He=3:20:2:75$ mixture at atmospheric pressure. The specific output energy was $\thicksim26$ J/liter and the total laser radiation energy was $\thicksim200$ J. The experimental results were used to suggest ways of improving further the $H_2-F_2$ laser parameters.