Development of a pulsed sextupole magnet system for beam injection at the Photon Factory storage ring

We have developed a pulsed sextupole magnet (PSM) system to demonstrate a new scheme of a beam injection at the Photon Factory storage ring (PF-ring) in KEK. We are going to install the PSM in this winter shutdown. Since a sextupole magnet has a characteristic of the parabolic magnetic field with no field at the magnetic center, it can give an effective kick to the injected beam at a distant position from the magnetic center and suppress effects on the stored beam at the beam injection. This enables us to inject the beam using the single PSM without a conventional pulsed local bump. The new injection scheme has a great advantage to achieve the top- up injection for a synchrotron radiation light source because it is not necessary to prepare a long straight section for the pulsed local bump system. The designed PSM has a length of 0.3m, a field gradient of about 13T/m² at a peak current of 3000 A, and a pulse full width of 1.2 musec in a half-sine waveform. In this paper, the current status of the development for the system is described.