Plasma electrical characteristics have been measured as a function of

-beam current density (J
B) and fluorine concentration for Ar, Kr, and F
2gas mixtures in order to identify the stable operating regime of KrF* laser interest. The data were obtained from a 120 cm
3active volume

-beam controlled discharge laser. The optimum F
2concentration was found to be 0.17 percent at J
B= 17.9 A/cm
2. This mixture also gave the best laser extraction efficiency and consequently produced the highest laser output energy. The dissociative electron attachment rate constant in the laser mixture was determined from the discharge voltage and current measurements.