Author: Sigrist, M.J.
Paper Title Page
TUPRB003 Virtual Shimming and Magnetic Measurements of two Long Period APPLE-II Undulators at the Canadian Light Source 1679
 
  • C.K. Baribeau, T.M. Pedersen, M.J. Sigrist
    CLS, Saskatoon, Saskatchewan, Canada
 
  Assembly and shimming have completed for a pair of long period APPLE-II type elliptically polarized undulators, QP-EPU180 and EPU142, at the Canadian Light Source. Both devices were shimmed using a weighted cost single-objective simulated annealing algorithm, with shims generated iteratively based on Hall probe and flipping coil data. In this paper we present detailed measurements on the two EPUs, including their magnetic and spectral performance across a wide range of gap and polarization operating points, as well as measured and predicted changes in field due to the virtual shimming.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB003  
About • paper received ※ 08 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB005 Photon Polarisation Modelling of APPLE-II EPUs 1687
 
  • M.J. Sigrist, C.K. Baribeau, T.M. Pedersen
    CLS, Saskatoon, Saskatchewan, Canada
 
  The CLS is currently commissioning two APPLE-II in-sertion devices (IDs), see [1], and constructing two more that allow for operation in ’universal mode’, i.e. selecting arbitrary photon polarisation parameters. Two of these devices will operate in the soft x-ray range where there is expected to be a significant change to polarisation at the sample due to transmission effects of the beam line op-tics. Arbitrary polarisation selection of the ID will counter transmission effects and enable circular polarisation at the sample position. A polarisation model of the device is derived which allows for the calculation of both the Stokes parameters and photon energy for any set point of ID gap and phase. Numerical solutions of these equa-tions allow the calculation of gap and phase set points for any desired photon energy or polarisation. The results of the polarisation model are compared with numerical simulations of the synchrotron radiation calculated using measured magnetic fields at various polarisation modes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB005  
About • paper received ※ 13 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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