Patent ID: 9105434
Filing Date: 2015-08-11
Classification: H01J

Abstract:
1. A cup-rod-plug-needle system that collects a source of electrons, allows internal space charge build-up and generation of an internal self-electric field build-up that then provides self-emission at a predetermined location of the needle in the system, the system comprising: a conducting medium at one end of a structure as the needle having a work function of less than Y eV, which needle acts as a cathode allowing field emission based on internal space charge build-up and generation of an internal self-electric field; a cup-rod assembly comprising a conducting rod between the needle and a cup to transport collected electrons, the conducting rod having a work function greater than X eV, the needle and the cup-rod assembly forming a cup-rod-needle assembly; an annular dielectric insulator as a plug, with the conducting rod passing through the plug, the insulator providing an electrical and mechanical barrier for mounting and a barrier for pressure differentials; a source of electrons to provide electrons into the cup, the cup acting as an anode; a beam drift tube that houses and enables electron transport to the cup-rod assembly, a surface of the cup and the conducting rod of the cup-rod assembly having a work function greater than X eV; the plug with rod passing through seals and terminate at one end of the beam drift tube; and wherein X−Y≧2.5.