A New Pulse Magnet for the RCS Injection Shift Bump Magnet at J-PARC

The 3-GeV rapid-cycling synchrotron at the Japan Proton Accelerator Research Complex has achieved the high-power beam operation equivalent to 1 MW. As a next step, a study of an upgrade is in progress to mitigate the dose exposure of the maintenance workers in a high residual dose environment and realize the further high intensity beam power. Regarding the upgrade plan's provisions for radiation protection, a new injection scheme has been proposed to make space available for radiation shielding. The total length of the two shift bump magnets of the four magnets is reduced for this purpose, while the other two magnets in the injection straight section remain unchanged. As a result, the two types of pulse magnets are connected separately in series and are excited by two independent power supplies, which are made possible by splitting the presently installed power supply. A structural analysis of the new shift bump magnet is in progress, including simulations of the effects of eddy currents and the coil temperatures by OPERA-3D. This paper describes preliminary results of this analysis and the outlines the modified power supply design.