SPring-8 Upgrade Project

Plans are underway for the upgrade of the SPring-8 facility, targeting completion in the early 2020's. Sustainability is a key guiding principle for the fourth-generation X-ray source - a beam emittance of around 100 pm.rad is pursued simultaneously with substantial energy-saving. The three key features of the design are (i) to replace the main dipole electric magnets with permanent magnets, (ii) to reduce the electron beam energy from 8 to 6 GeV, and (iii) to use the SACLA linac as an injector. Lowering the beam energy leads to reduction of (a) beam emittance, (b) magnetic fields, (c) the lengths of ID straight sections to maintain larger spaces for the magnets, and (d) the RF power consumption. Timeshare use of the SACLA linac enables beam injection to the upgraded ring with a low-emittance and short-pulsed beam as well as a reduction of injector power consumption by stopping the present injector consisting of a 1-GeV linac and a booster synchrotron. The outline of the upgrade plan will be reported with the current status of R&D started in 2015.