Bandwidth extension of an S-band, fundamental-mode eight-beam klystron

We present a general discussion of multiple-gap cavity characteristics and stability issues along with the detailed design of a five-cavity, broadband, high-power multiple-beam klystron (MBK). The predicted performance characteristics of this S-band fundamental-mode klystron circuit include a 3-dB bandwidth of 6.7% with peak power ~600 kW and an electronic gain of 33 dB. The circuit is powered by a 32 A, 45 kV eight-beam electron gun (Nguyen , 2004) whose design has been successfully tested in a previous narrowband MBK circuit (Nguyen , 2004), (Abe , 2005). The present circuit was designed and optimized with the three-dimensional particle-in-cell code MAGIC