A low-perveance electron gun for a high-efficiency Ka-band klystron

Self-consistent analytic and numeric design for a set of electron guns with a high beams quality to be used in high-power Ka-band klystrons is presented in this paper. The set of electron guns can be used in the high-power Ka-band klystrons in order to feed linear accelerating structures at 36 GHz with an estimated 20 MW input power by achieving an effective accelerating electric field in the (100–150) MV/m range. In the framework of the Compact Light XLS project, a short Ka-band linearizer by working at 36 GHz able to provide an integrated voltage of at least 15 MV is proposed for bunch-phase linearization. In order to optimize the Ka-band klystrons efficiency for achieving 20 MW RF output power, different electron guns, beam focusing channel designs and the RF beam dynamics are examined and discussed in this paper.