Operational experience with SLAC energy upgrade

To produce energies of over 50 GeV for SLC, all klystron stations on the accelerator are being upgraded to produce 250 MeV energy contribution per station. This involved installing new, higher power, longer pulse klystrons, upgrading klystron modulators to provide these higher voltage, longer klystron beam pulses, and a new interlock and protection system. A new VAX based diagnostic system including automated microwave measurements, klystron beam monitors, and modulator performance checks is being implemented. A block diagram of the klystron-modulator system is shown. To date, over half of the new klystrons have been installed and tested, the modulator upgrade program has converted 22 sectors (8 stations each) of modulators out of 30, and a four sector sampling of klystrons has been run at full SLC specs, namely 350 kV beam voltage, 3.5 microsecond pulse duration, peak output power in excess of 60 MW, and PRF of 120 pps. The klystron design, modulator design, interlock and diagnostic systems, and the results of the initial operation are discussed