Development of the repetitive pulsed power system for spallation neutron source beam extraction fast kicker

The spallation neutron source (SNS) is a next-generation high-intensity beam facility. The extraction kicker system is a high peak power, high average power, high-precision pulse-waveform, low beam impedance, and high repetition rate pulsed power system. It has been successfully designed and developed at Brookhaven National Laboratory, Upton, NY. The system consists of fourteen extraction magnet sections inside the ring vacuum chamber and fourteen identical high-voltage modulators located in the service building. The design features a Blumlein pulse-forming-network (PFN) based topology, a low beam impedance termination, a fast current switching thyratron, and low inductance capacitor banks. It has a maximum charging voltage of 50 kV, an open circuit output of 100 kV, and a designed maximum pulsed current output of 4 kA per modulator. The overall system output will reach multiple GW peak power with a 60 pulse/s repetition rate. A prototype modulator has been successfully built and tested well above the SNS requirement. The first batch of production modulators have passed all required tests at manufacture facility and delivered to Oak Ridge National Laboratory, Oak Ridge, TN, and the rest of the production units are under construction. The technical challenges and development results are presented in this paper.