High current density photoemissive electron source

Abstract

A high current, high current density cesium antimonide photoemissive electron source was constructed and tested over an extended period of time with small degradation. A photocurrent density of more than 3 A/cm2 was obtained with a performance drop of about 15% over a 70-h period. The slow decay was caused by cesium desorption from the cathode. Cesium evaporated onto the surface at the end of the test rejuvenated the photocathode to its original response. Such a photoemissive source has particular applications to electron beam lithography machines and high resolution, nondestructive electron microscopes.