Simple Laser-Driven, Metal Photocathodes as Cold, High Current Electron Sources

Abstract

Recent developments in excimer laser design have made near ultraviolet light intensities of several megawatts per square centimeter possible in unfocused beams. These advances and recent experiments indicate that high-current, simple-metal photoemissive electron guns are now feasible. Such guns should produce greater than 50 Amps per square centimeter of illuminated cathode surface. Additionally, these guns could operate at vacuums of 10"6 torr with no complicated system components inside the vacuum enclosure. The electron beam produced by such photoemission guns would have a very low emittance and high brightness. This beam would also follow closely the temporal characteristics of the laser pulse, making fast risetime, ultra-short electron beam pulses possible.