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  Sharples, E.; Dirsat, M.; Knobloch, J.; Muza, Z.; Vélez, A.: Design Development for the 1.5 GHz Couplers for BESSY VSR. In: Peter Michel ... [Ed.] : SRF2019, Proceedings of the 19th International Conference on RF Superconductivity, Dresden, GermanyGeneve: JaCoW, 2019. - ISBN 978-3-95450-211-0, p. WETEB9/797-801
  http://accelconf.web.cern.ch/AccelConf/srf2019/papers/weteb9.pdf

Open Access Version

Abstract:
The Variable pulse length Storage Ring (BESSY VSR) is a superconducting radio frequency (SRF) upgrade to the existing BESSY II storage ring at Helmholtz-Zentrum Berlin (HZB). BESSY VSR uses the RF beating of superconducting cavities at 1.5 GHz and 1.75 GHz to produce simultaneously long and short bunches. Higher power couplers capable of handling 13 kW peak power at standing wave operation, are required to provide an average power of 1.5 kW for both the 1.5 GHz and 1.75 GHz cavities. These couplers must also provide variable coupling with a range of Qext from 6×106 to 6×107 to allow flexibility to adjust to operating conditions of BESSY VSR. Here the full design development process for the 1.5 GHZ BESSY VSR coupler is presented including the design for a diagnostic prototype to ensure comprehensive monitoring of critical components during testing and cool-down.