PPPS-2013: Design and fabrication of a 10 MW, L-band, Annular Beam Klystron

Design improvements and steps toward fabrication of a 10 MW, 1.3 GHz Annular Beam Klystron are described. The principal design improvement is in the electron gun. Utilization of a CCR Controlled Porosity Reservoir (CPR) cathode improved the beam quality and allows reduction in the gun diameter. The cathode current density is 16 A/cm², which constitutes a modest loading for a CPR cathode and is consistent with very long life. At this density, no beam compression is required. This simplifies the gun optics, resulting in lower ripple. The smaller gun allows the use of a smaller diameter solenoid, reducing the solenoid power by about 30%.