Electron beam source

摘要

A high current density hollow cathode electron beam source for use in various E-beam apparatus is described. Bombardment of an electron emissive surface within the hollow cathode by energetic gas ions causes electrons to be emitted by secondary emission rather than thermionic emission effects. Once initialized by an external ionization voltage the device is essentially self sustaining and operates near room temperature, rather than at thermionic emission temperatures, and with reduced voltages.

The drawing shows the hollow cathode into which plasma gas is introduced via port 40 and the electron beam exits via aperture 36 to grid 58. lonization of the gas is initiated by voltage source 54 and the electron beam is sustained by voltage 57.