High brightness picosecond electron gun

Abstract

We have developed a high brightness picosecond electron gun. We have used it to replace the thermionic electron gun of a commercial scanning electron microscope (SEM) in order to perform time-resolved cathodoluminescence experiments. Picosecond electron pulses are produced, at a repetition rate of 80.7MHz, by femtosecond mode-locked laser pulses focused on a metal photocathode. This system has a normalized axial brightness of 93A∕cm2srkV, allowing for a spatial resolution of 50nm in the secondary electron imaging mode of the SEM. The temporal width of the electron pulse is 12ps.