Author: Babel, S.
Paper Title Page
THPHA020 LCLS-II Undulator Motion Control 1379
 
  • K.R. Lauer, A.D. Alarcon, C.J. Andrews, S. Babel, J.D. Bong, M. Boyes, J.M. D'Ewart, Yu.I. Levashov, D.S. Martinez-Galarce, B.D. McKee, H.-D. Nuhn, M. Petree, M. Rowen, Z.R. Wolf
    SLAC, Menlo Park, California, USA
  • D. Arbelaez, D. Bianculli, A.P. Brown, J.N. Corlett, A.J. DeMello, L. Garcia Fajardo, J.-Y. Jung, M. Leitner, S. Marks, K.A. McCombs, D.V. Munson, K.L. Ray, D.A. Sadlier, E.J. Wallén
    LBNL, Berkeley, California, USA
  • G. Janša, Ž. Oven
    Cosylab, Ljubljana, Slovenia
  • M. Merritt, M.L. Smith, R.J. Voogd, J.Z. Xu
    ANL, Argonne, Illinois, USA
  
  Funding: Department of Energy contract DE-AC02-76SF00515.
At the heart of the LCLS-II are two undulator lines: the hard x-ray (HXR) line and the soft x-ray line (SXR). The SXR line is comprised of 21 variable gap undulator segments separated by an interspace stands with a cam positioning system capable of positioning in 5 degrees of freedom (DOF). The undulator segment motion control utilizes the Aerotech Ensemble motion controller through an EPICS Soft IOC (input-output controller). Its drive system consists of a Harmonic Drive servo system with feedback from two absolute full-gap encoders. Additional Aerotech motion controllers are used to control the cam-positioning system and phase shifters of the interspace stand. The HXR line is comprised of 32 undulator segments each including an integrated interspace assembly. The segment girder is placed on two stands with a similar cam-positioning system as in the SXR line allowing for movement in 5 DOF. As one of the design goals of the HXR line was to reuse the original LCLS girder positioning system, the motion control system is an upgraded version of that original system, using RTEMS on VME with Animatics SmartMotors. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICALEPCS2017-THPHA020  
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THSH202 Design and Implementation of the LLRF System for LCLS-II 1969
 
  • C. Serrano, K.S. Campbell, L.R. Doolittle, Q. Du, G. Huang, J.A. Jones, V.K. Vytla
    LBNL, Berkeley, California, USA
  • S. Babel, A.L. Benwell, M. Boyes, G.W. Brown, D. Cha, J.H. De Long, J.A. Diaz Cruz, D.B. Greg, B. Hong, R.S. Kelly, A.L. McCollough, M. Petree, A. Ratti, C.H. Rivetta
    SLAC, Menlo Park, California, USA
  • R. Bachimanchi, C. Hovater, D.J. Seidman
    JLab, Newport News, Virginia, USA
  • B.E. Chase, E. Cullerton, J. Einstein, J.P. Holzbauer, D.W. Klepec, Y.M. Pischalnikov, W. Schappert
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract n. DE-AC02-76SF00515
The SLAC National Accelerator Laboratory is building LCLS-II, a new 4 GeV CW superconducting (SCRF) linac as a major upgrade of the existing LCLS. The SCRF linac consists of 35 ILC style cryomodules (eight cavities each) for a total of 280 cavities. Expected cavity gradients are 16 MV/m with a loaded QL of ~ 4 x 107. Each individual RF cavity will be powered by one 3.8 kW solid state amplifier. To ensure optimum field stability a single source single cavity control system has been chosen. It consists of a precision four channel cavity receiver and two RF stations (Forward, Reflected and Drive signals) each controlling two cavities. In order to regulate the resonant frequency variations of the cavities due to He pressure, the tuning of each cavity is controlled by a Piezo actuator and a slow stepper motor. In addition the system (LLRF-amplifier-cavity) was modeled and cavity microphonic testing has started. This paper will describe the main system elements as well as test results on LCLS-II cryomodules. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICALEPCS2017-THSH202  
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