High-current carbon-epoxy capillary cathode

Summary form only given. The results of experiments on the reproducible generation of electron beams in a vacuum diode supplied by a high-voltage pulse with amplitude of a -300 kV and duration of -600 ns are presented. A cathode based on carbon-epoxy capillary structure was used for generation of electron beams with current density of up to 600 A/cm² and a satisfactorily uniform cross-sectional distribution of current density. It was found that the source of the electrons is the plasma formed as a result of flashover inside the capillaries at an electric field -15 kV/cm. The cathode sustained thousands of pulses without degradation in its emission properties. Time- and space-resolved visible light observation and spectroscopy analyses were used to determine the cathode plasma´s density, temperature, and expansion velocity. It was found that the density of the cathode plasma density decreases rapidly versus the distance from the cathode. In addition, it was found that the main reason for the short-circuiting of the accelerating gap is the formation and expansion of the anode plasma.