W-band sheet beam klystron design

Sheet beam devices provide important advantages for very high power, narrow bandwidth RF sources like accelerator klystrons. Reduced current density and increased surface area result in increased power capability, reduced magnetic fields for focusing and reduced cathode loading. These advantages are offset by increased complexity, beam formation and transport issues and potential for mode competition in the overmoded cavities and drift tube. This paper describes the design issues encountered in developing a 100 kW peak and 2 kW average power sheet beam klystron at W-band including beam formation, beam transport, circuit design, circuit fabrication and mode competition.