PERFORMANCE OF SRF SYSTEMS IN LARGE-SCALE APPLICATIONS

Superconducting RF cavities have become more than just an anomaly in the world of particle accelerators. They have become a mature method of accelerating particles on a large scale. Accelerators at Argonne and KEK have demonstrated tha a reliable machine can be built and operated using superconducting technology. increasingly other large-scale accelerator projects, such as CEBAF and LEP, are coming on line utilizing this technology. Problems never observed before in normal conducting accelerators are being addressed at these accelerators. The nature of SRF systems requires that rigid machine interlocks and extreme vacuum requirements be imposed. The high Q accelerating cavities (greater than or equal to 10(5)) with their susceptibility to microphonics, requires sophisticatd feedback control systems. Other problems concerning gas discharges, tuning, gradient degradation and other phenomena must be dealt with. this paper discusses operational performance of large-scale SRF systems worldwide. Key operational issues concerning interlocks, controls and system reliability are included. Particular emphasis is placed on CEBAF's recent operational experiences because the author is closest to them and because CEBAF is rapidly approaching 80% of the installed superconducting cavities worldwide.(1)