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Title Investigations of Spatial Process Model for the Closed Orbit Feedback System at the Sis18 Synchrotron at GSI
  • S.H. Mirza, P. Forck, H. Klingbeil, R. Singh
    GSI, Darmstadt, Germany
  • H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
Abstract A closed orbit feedback system is under development at the GSI SIS18 synchrotron for usage during the whole acceleration cycle including the acceleration ramp. Singular value decomposition (SVD) is the most widely used technique in global closed orbit correction for eigenmode decomposition, mode selection and pseudo-inversion of Orbit Response Matrix (ORM) for robust calculation of corrector magnet strengths. A new faster inversion technique based upon Discrete Fourier Transform (DFT) has been proposed for SIS18 ORM exploiting the Circulant symmetry, a class of matrices which can be diagonalized by the DFT using only one row or column of the matrix. The existence of a clear relationship between SVD modes and singular values to DFT modes and coefficients for such matrices has been described. The DFT based decomposition of Circulant ORM gives hints on physical interpretation of SVD and DFT modes of perturbed closed orbit in a synchrotron. As a first practical application, DFT modes were used to provide robustness against sensor failures such as one or two malfunctioning BPMs.
Funding The work is supported by the Deutscher Akademischer Austauschdienst under contact No. 91605207
Paper download THMPA02.PDF [0.402 MB / 6 pages]
Slides download THMPA02_TALK.PDF [1.762 MB]
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Conference ICALEPCS2017, Barcelona, Spain
Series International Conference on Accelerator and Large Experimental Control Systems (16th)
Proceedings Link to full ICALEPCS2017 Proccedings
Session Mini-Oral
Date 12-Oct-17   16:45–17:15
Main Classification Feedback Control and Process Tuning
Keywords ion, closed-orbit, synchrotron, feedback, acceleration
Publisher JACoW, Geneva, Switzerland
Editors Volker RW Schaa (GSI, Darmstadt, Germany); Isidre Costa (ALBA-CELLS, Cerdanyola del Vallès, Spain); David Fernández (ALBA-CELLS, Cerdanyola del Vallès, Spain); Óscar Matilla (ALBA-CELLS, Cerdanyola del Vallès, Spain)
ISBN 978-3-95450-193-9
Published January 2018
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