The Spallation neutron source accelerator low level RF control system

The Spallation Neutron Source low level RF team includes members from Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. The team is responsible for the development, fabrication and commissioning of 98 low level RF (LLRF) control systems for maintaining RF amplitude and phase control in the front end (FE), linac and high energy beam transport (HEBT) sections of the SNS accelerator, a 1 GeV, 1.4 MW proton source. The RF structures include a radio frequency quadrupole (RFQ), rebuncher cavities, and a drift tube linac (DTL), all operating at 402.5 MHz, and a coupled-cavity linac (CCL), superconducting linac (SCL), energy spreader, and energy corrector, all operating at 805 MHz. The RF power sources vary from 20 kW tetrode amplifiers to 5 MW klystrons. A single control system design that can be used throughout the accelerator is under development and will begin deployment in February 2004. This design expands on the initial control systems that are currently deployed on the RFQ, rebuncher and DTL cavities. An overview of the SNS LLRF control system is presented along with recent test results and new developments