Abstract
Using a home-made Blumlein-type laser apparatus provided with a simple preionization device, output powers of the 248 nm KrF laser were measured for various mixture of F2/Kr/He at several total pressures ranging from 500 Torr to 2.65 atm. From the detailed investigation of the relation between the laser power and the mixing ratios of F2/Kr/He, three rules are deduced. To give theoretical basis for these rules computer simulation are carried out for a mixture experimentally found optimal at 2.65 atm. Fourty-four processes were taken into account, and eleven simultaneous differential equations are solved numerically. By varying nine parameters the observed laser pulse shape and delay time are well reproduced. Independent simulations for several different mixtures at a total pressure in the range 2.45-2.87 atm reproduced the three rules. Temporal behaviours of the electron temperature, concentrations of the electron and transient species, and the laser gain are analysed, and a reasonable lasing mechanism is deduced.
