Design and coldtest of high frequency interaction structure for X-band sheet beam klystron

In order to build an X-band sheet beam klystron with the peak output power of 5 MW, a high frequency structure has been designed through the three dimensional particle-in-cell simulations. The design method is consist of two steps, which are firstly finding a stable single-arm output cavity with the high energy extraction ability and secondly constructing a multi-cavity bunching section to produce the required bunching beam for driving the output cavity. The high frequency structure was symmetrically manufactured on two separate copper plates. By using the perturbation hole and the tuning block, the working mode of each cavity can be determined and the corresponding resonant frequency can be modified to conform with the design value. This interaction structure has been applied in the prototype tube that is presently built and will be tested in the coming months.