Characteristics of ion induced secondary emission electron gun

This paper presents some fundamental characteristics of a secondary emission electron gun using a pulsed glow discharge wire ion plasma source (WIPS). The positive helium ions extracted from WIPS are accelerated in vacuum toward the negatively biased cold cathode surface, which is set oblique to the ion loci in order to inject the emitted secondary electrons perpendicular to the foil window. The physical mechanisms governing the characteristics such as space charge and secondary electron emission have been reviewed. The dependence of such characteristics on the kinetic energy of incident ion and on the ion incidence position have been experimentally investigated. The experimental results are discussed together with the available theoretical models of each characteristic to establish the relative understanding of such phenomena in side-extraction-type secondary emission electron gun. The experimental results are further discussed in the light of a self-developed numerical simulation using the finite element method, which presents a good understanding of particle trajectories as well as potential distribution inside the gun geometry.