Optimizations of the F2/Ar/Ne gas composition and the optical cavity configuration were performed for an ArF* laser in the pressure range from 1 to 14 bar. The excitation source was a coaxial electron beam with a pulse length of 40 ns. From an active volume of 16 cm3a maximum output energy of 130 mJ at a total gas pressure of 14 bar was obtained when Ne was used as the buffer gas.