Dortmund 2021 – scientific programme
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AKBP: Arbeitskreis Beschleunigerphysik
AKBP 3: Radiofrequency
AKBP 3.5: Talk
Tuesday, March 16, 2021, 15:00–15:15, AKBPb
beam coupling impedance minimization of the SPS cavities using the generalized coupled S-parameter method — •Shahnam Gorgi Zadeh1, Erion Gjonaj2, and Ursula van Rienen1 — 1Universität Rostock, Rostock, Germany — 2Technische Universität Darmstadt, Darmstadt, Germany
The High Luminosity LHC (HL-LHC) project aims at increasing the luminosity in the LHC by up to a factor of ten. The longitudinal impedance of the Super Proton Synchrotron (SPS) poses a limitation on increasing the beam intensity in the injector chain. Beam dynamical studies have shown a large longitudinal impedance in the SPS cavities. Different types of higher order mode (HOM) couplers are used in the SPS cavities for the damping of different HOM passbands. The location of the HOM couplers in the cavities affects the damping of HOMs. Finding an efficient configuration requires solving a discrete optimization problem in which the cells that require a HOM coupler have to be identified to minimize the longitudinal impedance at the desired frequencies. The large size of the cavities, with a diameter of 0.75 m and a length which reaches up to 17 m, hinders the calculation of the beam coupling impedance by the conventional time-domain wakefield analysis methods. In this presentation, the Generalized Coupled S-parameter Calculation method, which is a domain decomposition scheme for the impedance calculation of large structures, is used to find an optimum HOM coupler configuration for the SPS cavities.
This research is funded by the Bundesministerium für Bildung und Forschung (BMBF) under Grant No. 05H18HRRB1.