Development of a durable, large area cathode for repetitive, uniform electron beam generation

Summary form only given, as follows. Electra is a large aperture krypton-fluoride laser under development for the inertial fission energy program. The laser will require dual 500 kV, 36 A/cm/sup 2/, uniform electron beams operating at 5 Hz for more than 10/sup 5/ shots. Experimental studies have been performed to develop a 3000 cm cathode capable of generating a 110 kA, 100 ns flat top beam pulse with minimal current density variation (<10%), fast turn-on time (<40 ns), negligible gap closure (<1 cm/us), and long lifetime (ultimately 10/sup 8/ shots). Time resolved electrical and optical data from the study of various dielectric fiber, carbon, and metal/dielectric cathodes will be presented.