Pulsed Resonant Charging Power Supply for the Spallation Neutron Source Extraction Kicker PFN System

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory uses fourteen pulsed modulators in the extraction system to deflect the proton beam from the accumulation ring to the target. Each individual pulse modulator is a pulse-forming network (PFN) located in a service building external to the ring tunnel. SNS is in the planning and development phase of a proton power upgrade (PPU) to increase the beam energy from 1.0 to 1.3 GeV, and the extraction system is required to provide the same deflection at the higher beam energy. Increasing the magnet current, by charging the PFN to a higher voltage, by 20% will provide the required deflection. The existing capacitor charging power supply is incapable of charging the PFN to higher voltages between the 60 Hz pulses; therefore, a new resonant charging scheme has been developed to charge to the PPU higher voltage within the available time. This paper describes the resonant charging power supply design and presents test results from a prototype operating on a full system test stand.