Rial, E.C.M.; Bahrdt, J.; Goslawski, P.; Meseck, A.; Ries, M.; Scheer, M.: Effect of Undulators on Transverse Resonant Island Orbits. In: IPAC 2021 : Proceedings of the 12th International Particle Accelerator Conference in Campinas, Brazil, 24–28 May 2021Geneva: JACoW, 2021. - ISBN 978-3-95450-214-1, p. TUPAB217/1-4
https://jacow.org/ipac2021/papers/tupab217.pdf
Open Access Version
Abstract:
For one week in October 2020, BESSY II offered a Two Orbit mode to users for the first time*. In this Two Orbit mode, the existence of transverse resonant island buckets** are exploited to store a second beam in the storage ring as an ?island orbit?, away from the primary beam axis. This mode was offered with free range of motion of the 12 out of vacuum undulators installed at the BESSY II ring. Diagnostics of the island orbit were limited to a single camera monitoring bending magnet radiation from a single dipole. A significant motion of the island orbit was observed on this diagnostic and correlated with undulator motion. This observation is reported, and simulations presented to demonstrate how this motion could arise. Correction schemes are suggested and discussed.