Design of a heavily damped superconducting cavity for SOLEIL

To provide the necessary beam power and RF voltage, while coping with coupled bunch instabilities, superconducting RF system is under study for the Synchrotron Light Source SOLEIL. A special arrangement combining a pair of single-cell cavities, strongly coupled through a large beam pipe, but ended with much smaller ones, and equipped with “classical” HOM dampers is investigated. Results of simulations, after optimization of the cavity shape, beam pipe opening and length, as well as the HOM-couplers design, are presented. Lastly, as beam power deposition and contribution to the overall ring impedance are of main concern, the short range wakefields of the overall cavity assembly have been also carefully studied