SNS RF system performance and operation

The spallation neutron source (SNS) Linac and accumulator ring utilize 100 radio-frequency (RF) systems for acceleration and bunching of the proton beam. Several different types of gridded tubes and klystrons are operated at 1, 2, 402.5 and 805 MHz, at power levels ranging from a few kilowatts to several megawatts, to drive several types of accelerating cavities, both normal- and super-conducting. The RF systems are standardized, especially in the Linac, to ease operation and maintenance. Phase and amplitude control is achieved with a digital low-level RF (LLRF) control system. The RF systems operate reliably and support production of a high-quality low-loss proton beam. Various modifications and upgrades have been made or are in progress to enhance system reliability and performance. Planning is well underway for a power upgrade that will require an additional 36 RF systems.