Theoretical analysis of the output performance of a transverse discharge pumped neon Penning laser (585.3 nm) using a mixture of Ne/H2is described. The validity of the kinetic model is confirmed by comparing the results to the experimental discharge and laser performance. It is theoretically shown that the optimum mixing ratio of the Ne/H2mixture is 1:2.5, and the optimum operating pressure is about 56 Torr. The model also predicts that the intrinsic efficiency reaches a peak of 8.5×10−6at an excitation rate of 0.5 MW/cm3under the optimum mixing ratio and operating pressure conditions. At excitation rates in excess of 0.5 MW/cm3the laser output power is slowly increasing and then saturates due to electron collisional quenching of the upper laser level. The laser power extraction is increased by laser injection seeding in order to rapidly build up the lasing. The improved intrinsic efficiency is about two times higher than without the injection seeding. The improved specific laser output is 8 W/cm3, therefore, a discharge volume of 125 cm3will be able to generate the peak laser power reaching 1 kW. This power value is sufficient to obtain the same treatment effect as the gold vapor laser used in photodynamic therapy. Moreover, by fitting this model to the experimental results of the laser output energy with a Ne/D2mixture, it is shown that the Penning ionization rate constant of H2is larger than that of D2. ©1995 American Institute of Physics.