MANAGEMENT FOR THE LONG-TERM RELIABILITY OF THE DIAMOND SUPERCONDUCTING RF CAVITIES

Diamond started operation with users in January 2007 and the Diamond storage ring superconducting RF (SRF) cavities were initially the largest single contributor to unplanned beam trips. Extensive effort has been dedicated to understand and improve the long-term stability of the SRF cavities. Our experience shows that the long-term stability of superconducting RF cavities relies heavily on the surface conditions. Gases accumulate on the cold surfaces with time due to its huge cryo-pumping capacity. We believe the accumulated gases are the cause of fast vacuum trips during operation. In Diamond, we have developed a systematic approach to control the long-term stability of the SRF cavities. We will discuss here our approach and also present the future work that should be completed.