Photoelectrons beam measurement from a magnesium cathode in a RF electron gun

摘要

The performance of a magnesium cathode in a one-and-half cell photocathode RF gun was measured at the Brookhaven Accelerator Test Facility (ATF). The frequency quadrupled Nd:YAG laser (266 nm) was used to stimulate the photoelectron emissions. For a normal incident laser pulse, the quantum efficiency of the magnesium at 10(sup (minus)7) torr was measured to be 5 (times) 10(sup (minus)4), which is more than 20 times the value for copper under similar conditions.