Continuous and pulsed electron beam production from an uninterrupted plasma cathode

Abstract

Electron extraction from a hollow cathode plasma discharge through a primary anode, biased with a DC accelerating potential, is controlled to produce either a pulsed or a continuous electron beam without interruption of the discharge. The beam is on while a secondary anode, interior to the hollow cathode, is electrically isolated. While the primary and secondary anodes are electrically connected, the beam is off. Pulses as short as 10μs have been produced, rise times are <1μs, the maximum beam-on duration is unlimited, and almost any duty cycle is possible. This source has been operated up to 3kV and has produced beams of up to 80mA.