Production of low-energy, high-current electron beams in a gun with a controlled explosive emission cathode

Abstract

The operating characteristics of an electron gun with a controlled explosive emission cathode have been investigated. The multichannel initiation of explosive electron emission from the (copper disk) cathode occurs due to the use of simultaneously operating resistively uncoupled arc plasma sources built in the cathode. Three gun operation options were tested, namely with a vacuum, a gas-filled, and a plasma-filled diode. In the last case, a plasma anode was formed using a high-current reflective (Penning) discharge or a hybrid discharge combining a Penning discharge with vacuum arcs. The cathode unit has shown a high emissive power (a factor of 1.5–2 higher than that of a conventional gun with a plasma anode and a multiwire copper explosive emission cathode). Stable operation of the gun was observed at an accelerating voltage of amplitude 5–30 kV, in contrast to at least 17–20 kV required for stable operation of the conventional gun. The gun operation with a vacuum and a gas-filled diode provided a considerably more efficient energy transfer from the power supply to the electron beam.