High voltage source with plasma emitter for large-section beam formation

A high-voltage electron source with plasma emitter on the base of two gas-discharge chambers installed coaxially at the expander ends is described. Electron extraction is exercised in the direction perpendicular to general axis of chambers through emission window located on the expander side. Beam of the 60x15 cm dimension with nonuniformity of current density distribution by cross section <=+10% is extracted out to atmosphere. Current density in the vacuum section constitutes 35 mA/cm2 at 250 kV accelerating voltage, 20 Hz frequency of current pulse repetition and 30 μs duration. Efficiency of electron extraction expressed by ratio of beam current in the chamber to discharge current does not depend on discharge current in the 5-40 A range at 150 cm2 atm/h general expenditure of working gas (air) and 5-6 mPa pressure in the vacuum chamber constitutes about 0.5. The source was used during 1.5 years in experiments on radiation solidification of polyester resins and for investigation of operation peculiarities of plasma emitters with large surface. Discharge chambers of the source worked smoothly during the whole approximately 1000 h operation period and they provided constancy of characteristics even after atmospheric breaks to vacuum chamber