Reliability and Operating Experience of the Lapf 805 MHz System

Over 750,000 hours have been accumulated on the klystrons and modulators that constitute the LAMPF 805-MHz rf system. The 1-1/4 MW klystrons, the floating-deck modulators and the modulator triodes are described. The operating data are summarized and the fault and failure modes are tabulated for the three major components of the system. The high-voltage processing and other maintenance required to keep this 86-kV system operating reliably are discussed. The crowbar rate, modulator-return rate and the modulator-fault rate are presented. The mean time between failures is > 53,000 h for the klystrons and > 45,000 h for the modulator triodes. The steps taken to produce such good reliability are discussed.