Increasing the reliability and service life of the cathode unit of an electron accelerator with extraction of a large-cross-section beam to the atmosphere

The design of an electron accelerator cathode unit with short filament elements in the form of a coil without a tightening mechanism is described. The advantage of the developed design over those of cathodes with long filaments with tightening mechanisms is shown. The nonuniformity of the beam-current density distribution behind the foil is <3%. The filament power required for cathodes in the form of coils is 20% lower than that for long-filament cathodes at the same beam-current density. Mechanical stresses leading to a breakdown of the cathode filaments are absent. The service life is determined mainly by the emission-caused wear of cathodes.