Design of a 100 MW X-band klystron

Future linear colliders require klystrons with higher peak power at higher frequency than are currently in use. SLAC (Stanford Linear Accelerator Center) is designing a 100-MW klystron at 11.4 GHz as a prototype for such a tube. The gun has been designed for 440 kV and 510 A. Transporting this beam through a 5-mm radius X-band drift tube presents the major design problem. The area convergence ratio pf 190:1 is over ten times higher than that found in conventional klystrons. Even with high magnetic fields of 6 to 7 kG, careful matching is required to prevent excessive scalloping. Extensive EGUN and CONDOR simulations have been made to optimize the transmission and RF efficiency. The EGUN simulations indicate that better matching is possible by using resonant magnetic focusing. CONDOR calculations indicate efficiencies of 45% are possible with a double output cavity. The results of the simulations and the status of the experimental program are discussed.<>