The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - UNPB AU - Dohlus, M. ED - Koscielniak, Shane ED - Satogata, Todd ED - Schaa, Volker RW ED - Thomson, Jana TI - XFEL Impedance Effects and Mitigation J2 - Proc. of IPAC2018, Vancouver, BC, Canada, April 29-May 4, 2018 C1 - Vancouver, BC, Canada T2 - International Particle Accelerator Conference T3 - 9 LA - english AB - A detailed impedance budget has been set up for the European XFEL, including the contributions from 2000 components, such as 824 cavities, 500 flanges, 220 BPMs (5 types, 78 pumps, 20 OTR screens, 7 collimators, 5 BAMs, 3 kickers, warm pipe etc. Both surface effects and geometric effects are important. Bunch compression and warm beam pipe require additional consideration. Most important are possible beam degradation affecting the FEL operation. Longitudinal wake fields lead to energy losses and unwanted energy spread. Even with mitigation, the wake-induced energy loss are larger than the energy losses due to the FEL lasing process. Various technical solutions have been developed to minimize the effects. This invited talk presents the basis for these simulations, their results, and comparisons with recent beam measurements in the European XFEL. PB - JACoW Publishing CP - Geneva, Switzerland ER -