Author: Gorgi Zadeh, S.
Paper Title Page
TUPAG08
Uncertainty Quantification for the Fundamental Mode Spectrum of the European XFEL Cavities  
 
  • N. G. Georg, J. Corno, H. De Gersem, U. Römer, S. Schöps
    TEMF, TU Darmstadt, Darmstadt, Germany
  • S. Gorgi Zadeh, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • A.A. Sulimov
    DESY, Hamburg, Germany
 
  Funding: The authors would like to acknowledge the support by the DFG (German Research Foundation) in the framework of the Scientific Network SCHM 3127/1,2 that provided the basis for this collaborative work.
The fundamental mode spectrum of superconducting cavities is sensitive to small geometry deformations introduced by the manufacturing process. In this work we consider variations in the equatorial and iris radii of the 1.3 GHz TESLA cavities used at the European XFEL. The cavities with slightly perturbed geometry are simulated using a finite element based eigenvalue solver. Employing uncertainty quantification methods such as sparse-grids, statistical information about the fundamental mode spectrum can be efficiently calculated. Moreover, using global sensitivity analysis, in particular Sobol indices, the impact of the individual geometry parameters on the quantities of interest, i.e. resonance frequencies, field-flatness and the cell-to-cell coupling coefficient, can be computed. We will explain important aspects of the uncertainty quantification methodology and give numerical results for illustration.
 
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TUPAG14 Constrained Multi-Objective Shape Optimization of Superconducting RF Cavities to Counteract Dangerous Higher Order Modes 293
 
  • M. Kranjcevic, P. Arbenz
    ETH, Zurich, Switzerland
  • A. Adelmann
    PSI, Villigen PSI, Switzerland
  • S. Gorgi Zadeh, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
 
  High current storage rings, such as the Z operating mode of the FCC-ee, require superconducting radio frequency (RF) cavities that are optimized with respect to both the fundamental mode and the dangerous higher order modes. In order to optimize the shape of the RF cavity, a constrained multi-objective optimization problem is solved using a massively parallel implementation of an evolutionary algorithm. Additionally, a frequency-fixing scheme is employed to deal with the constraint on the frequency of the fundamental mode. Finally, the computed Pareto front approximation and an RF cavity shape with desired properties are shown.  
slides icon Slides TUPAG14 [3.001 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAG14  
About • paper received ※ 19 October 2018       paper accepted ※ 10 December 2018       issue date ※ 26 January 2019  
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