Pulse electron gun

Claim 1

An electron gun for an electron discharge device, which comprises: 1. an evacuated, cylindrical cavity resonator having an axis of symmetry; 2. a plurality of photoemissive electron sources disposed about the periphery of one end of said cylindrical cavity resonator, said electron sources being capable of generating a primary electron beam within said cavity; 3. a plurality of annular electrodes within said resonator, coaxial with said axis of symmetry, successive annular electrodes having an increased radius, the annular electrode closest to the periphery of said resonator having the greatest radius, each of said electrodes being capable of emitting secondary electrons; 4. means for supplying a source of radio frequency signals to said cavity resonator, said signals having a frequency corresponding to the resonant frequency of said cavity, whereby a standing wave is established in said cavity, said electrodes being positioned, with respect to said standing wave, at points of different voltage magnitude in said cavity; 5. a source of light; 6. optical means for transmitting light from said source to said plurality of photoemissive electron sources to produce said primary electron beam; and 7. means, located proximate said axis of symmetry, for extracting said primary beam and the beam comprised of the secondary electrons from said plurality of annular electrodes, for subsequent utilization.