A plasma-cathode electron source for focused-beam generation in the fore-pump pressure range

A plasma electron source is described that forms a focused beam in the range of fore-pump pressures. Plasma is generated in a hollow-cathode discharge. Electrons are extracted through a single emission hole in the anode. The source provides an electron-beam current of up to 0.1 A and an energy of up to 20 keV. The beam diameter at the half-height of the current-density distribution is <= 1.4 mm, and the beam-power density is as high as 1.5 kW/mm(2).