Design of the Injection Bump System of the 3-GeV RCS in J-PARC

The injection bump system of the 3-GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump) and two vertical painting magnets (v-paint bump). The shift bump magnets, which are connected in series in order to form a closed bump orbit. The injection bump system needs the power supplies with the high speed and flexible current pattern. Furthermore, the tracking error is required less than 1.0% for 1.0 mus pulse current. The power supplies with the IGBT (Insulated Gate Bipolar Transistor) chopper units, which are controlled by the switching frequency over 60 kHz, realize its performance. The decay time of the shift bump power supply is less than 200 microseconds