Design and development of thermionic emission microscope for the characterization of multi-beam cathode

Abstract Thermionic emission microscope (THEM) is an important analytical research tool to study spatial emission distribution of a thermionic cathode. The criticality of its design and development stems from the need to characterize the inhomogeneous emission nature of the impregnated cathode surface. In this paper the design of lens and deflection plates for studying multi-beam cathode (MBC) is presented. To understand the electron optical performance of THEM, simulations were carried out using the simulation tools 2D-TRAK and Omni TRAK. These results were further validated using another software tool CST Particle Studio. The influence of various parameters of MBC such as protrusion, diameter of button and inter-button spacing have been studied.