Simple laser-driven, metal-photocathode electron source

Abstract

An ArF excimer laser was used to produce photoelectrons from common metal surfaces at modest vacuum. The photoelectrons are subsequently accelerated across an anode-cathode gap. Both space-charge and emission-limited flow were examined. The temporal characteristics of the emission-limited electron beam produced by this device are nearly identical to those of the laser pulse used to produce the photoemission. In the space-charge-limited case, a rise time of 3 ns was obtained. Maximum current densities of 70 A/cm2 were achieved.