150-MW S-Band Klystron Program at the Stanford Linear Accelerator Center

Two S-Band klystrons operating at 150 MW have been designed, fabricated and tested at the Stanford Linear Accelerator Center (SLAC) during the past two years for use in an experimental accelerator at Deutsches Elektronen Synchrotron (DESY) in Hamburg Germany. Both klystrons operate at the design power, 60 Hz repetition rate, 3 ps pulsewidth, with an efficiency > 40%, and agreement between the experimental results and simulations is excellent. The 535 kV, 700 A electron gun was tested by constructing a solenoidal focused beam-stick which identified a source of oscillation, subsequently engineered out of the klystron guns. Design of the beam-stick and the two klystrons is discussed, along with observation and suppression of spurious oscillations. Differences in design and the resulting performance of the klystrons is emphasized.