Vélez, A.; Glock, H.-W.: Superconducting Radio-Frequency for High-Current CW Applications. In: Eberhard Jaeschke ; Shaukat Khan ; Jochen R. Schneider ; Jerome B. Hastings [Eds.] : Synchrotron Light Sources and Free-Electron LasersCham: Springer, 2019 Springer Reference Live. - ISBN 978-3-319-04507-8, p. 1-20
10.1007/978-3-319-04507-8_59-1
Abstract:
Along the last decade, the Helmholtz-Zentrum Berlin has accomplished the goal to commission and successfully run a third-generation synchrotron light source (BESSY II). Based on the expertise gained through the development and operation phases of such a facility, HZB is ready to realize new accelerator approaches. To this end new projects based on superconducting technologies are currently under development. The first one consists of a demonstrator 50MeV ERL facility (bERLinPro) providing high current and low emittance simultaneously. At the same time, a novel application of a superconducting high harmonic cavity system will be used for a major upgrade of the BESSY II facility to the BESSY variable pulse-length storage ring (BESSY VSR) for a next-generation storage-ring light source as an alternative to diffraction-limited storage rings. To achieve such goals, the developed systems need to be capable of continuous high-power operation. In particular BESSY VSR aims to operate with a high current beam (300 mA) and a challenging filling pattern. As a consequence HZB is developing techniques to realize extremely efficient damping of beam-induced fields on cavity systems with accurate impedance control and thus avoiding beam instabilities. This chapter will present an overview on these techniques by illustrating the design decisions taken for bERLinPro and BESSY VSR in comparison with other technological state-of-the-art options. It therefore will give a detailed insight on the concepts, risks, and benefits of various technical solutions.