Pumping of the GARPUN wide-aperture excimer laser by counterpropagating electron beams

The transport of high-current electron beams from vacuum diodes to the laser chamber of the GARPUN wide-aperture excimer laser was investigated experimentally and theoretically. The processes involving the transport of fast electrons in argon and krypton in a longitudinal magnetic field were also studied. Pumping by counter-propagating electron beams resulted in the deposition of up to 2.1 kJ of energy into the active medium of the laser, which corresponded to a specific excitation power of ~0.8 MW cm^-3 with an inhomogeneity of less than 20% over a 12 cm × 18 cm aperture. The efficiency of the energy deposition by electron beams was ~60% and the overall efficiency of the laser pumping system was ~16%.