High Voltage DC Power Supplies for RF-Klystron-Transmitters in Accelerators and Storage-Rings

For klystrons operating in high duty-cycle or cw-modes, the power supplies must meet specific requirements beyond ordinary power supply characteristics. Typical klystron beam voltages range between 40 and 80 kV. Capacitor banks are necessary to avoid rf-phase fluctuations related to beam voltage fluctuations. Hence the stored energies are very high, typically around 20000 Joules. In case of arcing the klystrons can withstand only energies of up to approx. 20 Joules. Therefore crow bar systems are of vital interest in klystron transmitter power supplies. This paper describes design of the PETRA storage ring klystron power supplies and the operational experience.