Design of an Electron Optical System for a 263 GHz Sheet Beam TWT

A novel approach toward a new high compression sheet beam electron gun and an advanced hybrid periodic permanent magnet-periodic quadrupolar magnet (PPM-PQM) for the development of a 263 GHz sheet beam Traveling Wave Tube (TWT) is reported herein. The electron gun is designed to operate at 19 kV and to produce a sheet electron beam with an elliptical cross section of 0.6 mm (width) x 0.08 mm (height) compressed from a flat 0.8 mm diameter round cathode, providing a beam current density of 300 A/cm ² , The modified PPM-PQM focusing system is specifically designed to transport the sheet electron beam in a 0.7 mm width and 0.12 mm height beam tunnel. The designed beam transport system achieves ~100% transmission throughout the entire 4S-mm long beam tunnel with CST Particle Tracking simulation.