Design Study of a High-Power Ka-Band High-Order-Mode Multibeam Klystron

Compactness and cost-effectiveness are two major concerns in the development of a Ka-band linearizer, which is a crucial accelerator component of the European CompactLight project. A higher order mode (HOM) multibeam Klystron (MBK) could accommodate a higher distributed electron current with a low operating voltage of 60 kV, thus making it competitive to deliver high RF power at high frequency compared with a single beam Klystron or a fundamental mode MBK. In this article, the modeling and design study of the 36-GHz HOM MBK is presented. The development of a double compression multibeam (MB) optics system is also elaborated in this article. The performance validation of such a device was done using sophisticated 3-D particle-in-cell (PIC) computer simulations of the entire device. PIC simulations confirmed that a power level of 2.5 MW is attainable with an efficiency of 35%.