Cesiated porous molybdenum converter for intense negative ion sources

Abstract

Maintaining the proper low work function surface in steady-state high-current-density negative ion sources is difficult, due to intense ion bombardment of the surface. Experiments were performed in which liquid cesium was forced through a porous molybdenum converter in order to obtain a low work function, while at the same time allowing the surface to be cooled. In a small steady-state hollow cathode discharge source, the H− yield from a porous molybdenum converter was five fold higher than from a solid molybdenum converter which relied on the conventional method of cesium coverage by vapor deposition.