Neumann, A.; Abo-Bakr, M.; Anders, W.; Burrill, A.; Khan, V. F.; Knobloch, J.; Wesch, S.: Booster cavity and fundamental power coupler design issues for bERLinPro. In: Christine Petit-Jean-Genaz ... [Ed.] : IPAC2014: Proceedings of the 5th International Particle Accelerator Conference. , 2014. - ISBN 978-3-95450-132-8, p. WEPRI007/2490-2492
http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepri007.pdf
Open Access Version

Abstract:
HZB has started building the 50 MeV, 100mA demonstrator energy-recovery-linac (ERL) facility bERLinPro. The high power injector system needs to deliver this beam at 6.5 MeV by combining the energy gain of a 1.4 cell SRF photo-injector and three Cornell style 2-cell booster cavities. One booster cavity will be operated at zero-crossing for bunch energy chirping. Thus two booster cavities have to deliver 2MV each requiring a strong coupling with a loaded Q of 105. To house the two envisaged KEK fundamental power couplers (FPC) with the cavity, the geometry was slightly modified. Further, to increase coupling and reduce transverse kick effects to the beam, a ”golf-tee” antenna tip was designed. This paper summarizes the SRF challenges for the booster cavities, the operational conditions and the modification to the KEK couplers, including tracking calculations to estimate the coupler kick effect to higher order.