Author: Galek, T.
Paper Title Page
WEP07 Traveling Poles Elimination Scheme and Calculations of External Quality Factors of HOMs in SC Cavities 152
 
  • T. Galek, T. Flisgen, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • A. Neumann
    HZB, Berlin, Germany
  • B. Riemann
    DELTA, Dortmund, Germany
 
  Funding: Funded by EU FP7 Research Infrastructure Grant No. 227579 and funding approved by German Federal Ministry of Research & Education, Project: 05K10HRC
The main scope of this work is the automation of the extraction procedure of the external quality factors Qext of Higher Order Modes (HOMs) in Superconducting (SC) radio frequency cavities [*]. The HOMs are generated by charged particle beams traveling at the speed of light through SC cavity. The HOMs decay very slowly, depending on localization inside the structure and cell-to-cell coupling, and may influence succeeding charged particle bunches. Thus it is important, at the SC cavity design optimization stage, to calculate the Qext of HOMs. The Traveling Poles Elimination (TPE) scheme has been used on scattering parameters spectra to obtain external quality factors. The combination of Coupled S-Parameter Calculations (CSC) method and vector fitting procedure allows us to study very complicated structures in much better details and almost automated extraction of HOMs' Qext factors. The results are also reasserted by careful eigenmode analysis of the SC cavity. The S-Parameter and eigenmode simulations were performed using CST Microwave Studio.
*Axel Neumann et al., "Status of the HOM Calculations for the BERLinPro Main Linac Cavity", FRAAC3 (this conference)
 
 
FRAAC3 Status of the HOM Calculations for the BERLinPro Main Linac Cavity 278
 
  • A. Neumann, W. Anders, J. Knobloch
    HZB, Berlin, Germany
  • K. Brackebusch, T. Flisgen, T. Galek, K. Papke, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • B. Riemann, T. Weis
    DELTA, Dortmund, Germany
 
  Funding: Work supported by Federal Ministry for Research and Education BMBF under contract 05K10HRC
The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW LINAC technology and expertise required to drive next-generation Energy Recovery Linacs (ERLs). Strongly higher order mode (HOM) damped multicell 1.3 GHz cavities are required for the main linac. The cavity under study is an integrated design of the Cornell base cell with JLab HOM waveguide couplers. Modifications to the end group design have also been pursued, including the substitution of one waveguide by a HZB-modified TTF-III power coupler. In this talk the progress in HOM calculations to avoid beam-breakup instabilities for the favored cavity structure will be presented.
 
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