A Periodic Cusped Magnetic - Quad Magnetic Focusing System for Low Voltage Ultra-Compact W-Band Klystron

摘要

A Periodic Cusped Magnet (PCM) - Tunable Quadrupolar Magnet (TQM) is proposed to focus the sheet electron beam of a low voltage W-Band, ultra-compact continuous wave sheet beam klystron (LUWK). The design utilizes a PCM to prevent the vertical beam spreading, and a TQM to control transverse beam spreading the force. Employing the PCM-TQM not only benefits the compact size of the LUWK, but it also mitigates the Diocotron instability of the sheet beam. Using the PCM-QM focusing system, the MAGIC-3D simulations show that an elliptical sheet beam with transverse size 6.0 mm x 0.5 mm can achieve a 99% cold beam transmission, and a 97% hot beam transmission through a 140 mm beam tunnel.