Andreas, F.; Abo-Bakr, M.; Armborst, F.; Goslawski, P.: Developing Beam Optics for the BESSY VSR Project. In: Mark Boland ... [Ed.] : IPAC 2019, Proceedings of the 10th International Particle Accelerator Conference: Melbourne, Australia, 19-24 May 2019. Geneva, Switzerland: JACoW Publishing, 2019. - ISBN 978-3-95450-208-0, p. MOPGW014/94-97
http://jacow.org/ipac2019/papers/mopgw014.pdf
Open Accesn Version

Abstract:
At BESSY II due to the continuously increasing interest in short pulse operation, a major upgrade of the ring will enable simultaneous storage of long and short bunches. This Variable pulse-length Storage Ring (VSR) will be achieved by the installation of additional superconducting high gradient cavities. The cavities will be assembled into one cryomodule in one of the straights of the storage ring. As this module needs more space then initially assumed, one possible solution is to remove two quadrupoles to gain available installation length. The quadrupoles were switched off in simulations and the lattice was optimized with regard to the linear order. The best solution found was transferred to the storage ring, where storage of high current with reasonable injection efficiency and lifetime was possible. The proposed optics has to be further optimized in terms of nonlinear beam dynamics, but has shown that an available installation length can be increased.