Electron beam generation in high voltage glow discharges

Summary Form only given, as follows. The generation of intense CW and pulsed electron beams in glow discharges is reviewed. Glow-discharge electron guns operate at a pressure of the order of 1 torr and often have an advantage in applications that require a broad-area electron beam in a gaseous atmosphere. Abnormal glow discharges can be designed to sustain multikilovolt voltage drops in the cathode sheath. Electron emission from the cathode surface is produced following the bombardment of ions accelerated in the sheath and of fast neutral atoms created by charge-transfer collisions in that region. By selecting high-electron-yield cathode materials, multikilowatt CW (continuous-wave) electron beams have been operated with efficiencies up to 80% and current in excess of 1 A. Pulsed currents approaching 1000 A with electron beam current densities >10 A/cm/sup 2/ have been obtained for 50-100-kV discharges. Broad-area electron beams have also been created by accelerating thermal electrons from glow-discharge plasmas in the plasma between two grids.<>