The study of a new HMBA lattice for PF-AR

The Photon Factory Advanced Ring (PF-AR) is a storage ring light source of hard X-ray region dedicated to the single bunch operation, and has been operated for users about 30 years from 1987. The lattice and optics are almost not changed from the original one as the TRISTAN booster ring constructed in 1984. The lattice employs FODO structure and the horizontal emittance for the 6.5 GeV user-run is about 300 nmrad. In order to acquire the higher brilliance competitive with the state-of-the-art light sources, the full replacement of the accelerator with the ESRF-type HMBA (Hybrid multi bend achromat) lattice is examined. In order to geometrically fit the new lattice to the present PF-AR tunnel, the new ring consists of 12 cells with four long straight sections. The emittance is improved to about 500 pmrad at 3 GeV. With the present user experimental hall at the north of the ring, at least eight undulator beam lines can be constructed. The simulated dynamic aperture is about 1.5 cm at the long straight section with reasonable magnetic errors and COD correction. The conventional injection system with kicker and septum magnets is adoptable and the Touschek lifetime is about 6 hours. (author)