Design and Preliminary Performance of the New Injection Shift Bump Power Supply at the J-PARC 3-GeV RCS

A new power supply for the injection shift bump magnet at the Japan Proton Accelerator Research Complex 3-GeV Rapid Cycling Synchrotron has been designed with the energy upgrading of the linear accelerator to 400 MeV. The power supply is required to output the maximum current of 32 kA, which is 1.6 times the present current. Moreover, peak current ripple noise should be less than ±0.2% of the setting current in a range from 10 kA to 32 kA output current. The insulated gate bipolar transistor chopping system in the present power supply produces the continuous current ripple noise due to the switching, which resonates with the load and excites a forced beam oscillation at about 96 kHz in the injection stage. So, the circuit structure of the new power supply has been changed from the insulated gate bipolar transistor chopping system to the pulse forming network system by switching capacitors. The whole power supply is comprised of 16 banks, each of which outputs 2 kA at 13.2 kV maximum. The first bank has been manufactured and the characteristics were evaluated in the factory. This paper summarizes the design and the preliminary experimental results of the new power supply.