Reliability and lifetime predictions of SLC klystrons

Life expectancy predictions are presented for the SLC (Stanford Linear Collider) klystrons, with particular emphasis on cathode life. Based on these data, some of the principal modes of failure are discussed. It is concluded that the future performance of SLC 5045 klystrons looks very optimistic. Klystron MTBF (mean time between failure) presently exceeds 35000 hrs and is increasing as more operational time is accrued. Although most of the operating hours have been at reduced pulse repetition rate, no cathode failures due to aging have been seen. RF instability problems have been reduced by changing the gain cavity frequencies. Output window problems have also been reduced by modifying the window orientation to minimize the effect of contaminants and by replacing the single window with a two-window output. High-voltage ceramic insulator failures have been solved by modifying the electromagnet corona shield