High power, CW, UHF klystrons for storage ring applications

The klystrons to be described in this paper operate at a fixed frequency of 358.54 MHz. They are designed for 125 kW CW with an efficiency in excess of 50 percent. Four cavities are used resulting in a gain of approximately 50 dB. Design values of operating voltage and microperveance are 41 kV and 0.7, respectively. The klystrons are required to be stable when working into any accelerator VSWR up to 2:1 and at any phase angle. This requires the versatile and rugged output system to be described. An operating efficiency of 57 percent is reported and the highest output power is 160 kW CW at 42.5 kV.