Design Approach for a Miniaturized Pseudospark-Based High-Current-Density Sheet Electron Beam Source

Abstract

In this article, the design approach for a miniaturized high-current-density sheet electron beam (SEB) source has been reported. A study through simulation using COMSOL Multiphysics has been carried out to analyze the role of geometrical parameters of the hollow cathode in miniaturized SEB generation. These geometrical parameters play a very important role in defining the discharge inside the hollow cathode geometry and subsequent beam generation through a rectangular aperture. The hollow cathode diameter “D”, the length of the hollow cathode “L”, and the aspect ratio of the sheet beam defined by the aperture size in front of the hollow cathode region have been optimized for the generation of a SEB. The ratio of the length to the width of the rectangular aperture defines the aspect ratio of the SEB. It has been found that the beam aspect ratio plays an important role in the penetration of the accelerating field inside the hollow cathode geometry, which affects the transient behavior of the discharge. The hollow cathode dimensions have been optimized for the applied gap voltage varying between 15 and 25 kV, while the beam aspect ratio has been analyzed for the range between 5:1 and 12:1 keeping the fill factor constant.