Generation of High-Current Electron Beams in Diodes With Large-Area Explosive Emission Cathodes

This paper reports the investigation of several types of large-area (20-40 cm
²
) explosive emission cathodes different in shape and emitting surface material. We concentrated on the cathodes with emitters made of dense fine-grained graphite and carbon-epoxy capillary arrays (multicapillary cathodes), but also considered a cathode with copper emitter. We experimented with planar and profiled (Ernst profile) emitters and a graphite ring-type cathode. The velocity of cathode plasma expansion, the stability of operation, and the homogeneity of generated beams are compared for different cathodes. The current density distribution over the beam cross section is examined using the beam imprint on the radiochromic film. The pepper pot method is used to find whether the beam is converging or diverging.