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Li, Y.

Paper Title Page
WEPPH005 Magnet Sorting for the European XFEL Hybrid Undulator - Comparing Study 326
 
  • B. Faatz, J. Pflueger, Y. Li
    DESY, Hamburg
 
  Current permanent magnet material quality is insufficient to obtain field qualities in undulators, which satisfy FEL requirements. Therefore position and orientation of magnets have to be carefully chosen in order to obtain mutual cancellation of field errors. In this paper we compare two different sorting schemes, simulated annealing and a straight forward paring method. They are applied to a 5m prototype structure built for the European XFEL facility. The algorithms of these two methods are described in detail and the sorting results and the expected field qualities are carefully compared.  
WEPPH006 Study of Undulator Deformation Tolerance for the European XFEL 330
 
  • B. Faatz, J. Pflueger, Y. Li
    DESY, Hamburg
 
  The undulators for the European XFEL use NdFeB type permanent magnets. Even for perfect magnet material, the undulator quality degrades due to mechanical limitations, such as girder deformation, and temperature variation. Since the beam orbit can always be corrected, the main effect will be a variation in slippage between electrons and photon beam along the undulator. A careful estimation of the error budget is needed to avoid cost driving hardware efforts. We modeled deformation, gap variation and temperature error and used GENESIS to simulate the effect on the performance of the European XFEL.