Multicomponent KrF gas laser operating above atmospheric pressures

A study was made of the dependence of the radiation energy emitted by a coaxial KrF laser pumped by an electron beam on the composition and pressure of the gas mixture. Measurements were made on two-component (Kr–F₂), three-component (Ar–Kr–F₂), and four-component (Ar–Kr–Ne–F₂) gas mixtures. The maximum total pressure mixture was 12 atm. The active volume of the laser was 16 cm³ and the diameter of the anode tube was 1cm. The experiments were carried out using a charging voltage of 280 kV and a current of 7.5 kA; the pulse duration was 30 nsec. A study of the two-component mixtures showed that the maximum output energy corresponded to a partial F₂ pressure of 10 mbar so that this pressure was used in all the other measurements. The optimal pressures in the three-component mixtures of gases for a current of about 250 A/cm² density were 4.5 atm Ar and 0.5 atm Kr, whereas in the case of the two-component mixtures the optimal pressure was 2 atm. A study of the four-component mixtures revealed a positive effect of Ne on the output radiation energy: this energy increased on reduction in the Ar concentration and on increase in the total pressure of the gas mixture. The highest output energy was achieved p_Ar = 490 mbar and p_Kr=500 mbar, but the optimal total gas pressure exceeded 12 atm. The physical efficiency of the laser, corresponding to the maximum output radiation energy, was 7%.