HIGH-VOLTAGE ELECTRON SOURCE WITH PLASMA EMITTER FOR FORMING BEAMS WITH A LARGE CROSS SECTION.

The high-voltage electron source with a plasma emitter described is based on two gas-discharge chambers set up coaxially on the ends of an expander. Electrons are extracted in a direction perpendicular to the general axis of the chamber through an emission window installed in the side wall of the expander. A beam measuring 60 multiplied by 15 cm with a nonuniformity less than equivalent to plus or minus 10% in the distribution of the current density over the cross section is brought out into the atmosphere. With an accelerating voltage of 250 kV, a current-pulse repetition rate of 20 Hz, and a pulse duration of 30 mu sec, the current density in the vacuum gap is 35 mA/cm**2.