Measuring the extension an electron bunch from arsenide-gallium photocathode

To apply SHF photogun as an electron injector in linear accelerators it is necessary to determine the increase of duration of electron emission from gallium-arsenide cathode as compared to the laser pulse duration. Results of investigations into this problem are described. According to the data obtained, a cathode, based on a thick GaAs crystal has a low response time. The upper limit of electron cluster lengthening at the expense of finite photocathode response time, equal to 30 ps for 532 nm laser radiation wave length is ascertained. 2 refs.; 3 figs