Design and Operation of a High Power L-Band Multiple Beam Klystron

A 10 MW, 1.3 GHz multiple beam klystron (MBK) has been developed for the DESY X-FEL and International Linear Collider projects. The device uses six electron beams set off-axis on a large bolt circle which interact with a combination of higher-order-mode and conventional klystron cavities to efficiently produce high power RF. Extensive two and three dimensional simulations were used to design the device. Recent test results have validated the basic design concepts and procedure. Ten megawatts of peak and 150 kW of average power have been stably generated with 59% efficiency and 48 dB of gain.