부산대학교 도서관

A W-band electron gun design under development has been modified for improved beam optics and reduced electric field stress. This design is based on a design presented by Nguyen et al. [1]. The main effort has been focused on designing magnet pole pieces that would provide an optimum magnetic field transition with sufficient distance from the cathode for the placement of focusing electrodes. Variations of the magnet pole pieces were tested with Poisson and MICHELLE [2], [3] to find a configuration that would focus the beam without requiring extensive changes to the electrode geometry; an effort was also made to avoid saturation of the magnetic field inside the pole piece and to avoid excessive electric field strength at the electrodes.