The role of Ne, Ar, and Kr as a buffer gas was investigated in a KrF laser pumped by a coaxiale-beam. The coaxial diode has a length of 20 cm and the anode tube diameter is 1 cm. The tube can be pressurized with the laser gas mixture up to 12 bar while a current density of 250 A/cm2can be achieved. It is found that both the maximum energy extraction and the optimized gas pressure with each buffer gas increase in the sequence Kr-Ar-Ne. From the experimental results, the quenching parameters of Kr, Ar, and Ne are deduced.