Design of CEPC High Efficiency Multibeam Klystron

This paper presents the design and simulation of CEPC 650MHz/800kW CW multibeam klystron. To get high efficiency, single beam perveance is chosen to be as low as $\pmb{0.2\mu} \mathbf{P}$. On the other hand, beam voltage is 54kV which could be considered as a safe vale in CW operation. Three dimensional PIC simulations of CEPC MBK predict an efficiency of 80%.