Author: Trakhtenberg, E.
Paper Title Page
MOPPP079 Magnetic Tuning of the APS Wiggler as a Study for Tuning the NSLS-II Damping Wiggler 747
  • I. Vasserman, M. Abliz, E. Gluskin, E. Trakhtenberg, J.Z. Xu
    ANL, Argonne, USA
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
A wide variety of tuning techniques has been developed and employed at Advanced Photon Source (APS) in the course of tuning insertion devices for use on the APS storage ring, the APS free electron laser, and in assisting with the LCLS undulator tuning. The tuning requirements for the National Synchrotron Source II (NSLS-II) damping wigglers are very demanding and include limits on the off-midplane field integrals that are new in the repertoire of undulator magnetic tuning. The goal of this study was to assess the applicability of existing tuning techniques to meeting the off-midplane requirements of NSLS-II. Tests were run using an available APS 8.5-cm-period wiggler. In addition to existing techniques, a special new shim design was tested. This report summarizes the results of these tests and shows that the wiggler can be tuned to the required specifications on the midplane over the requested ±15 mm in the horizontal direction. In the vertical direction, however, the specifications could only be met within ±0.5 mm. This falls short of the ±15 mm by ± 3 mm good-field region that is sought by NSLS-II.
MOPPP080 New Concepts for Revolver Undulator Designs 750
  • B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg
    ANL, Argonne, USA
  • M.B. Patil
    Impact Engineering Solutions, Brookfield, USA
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation.
MOPPP078 Status of the First Planar Superconducting Undulator for the Advanced Photon Source 744
  • Y. Ivanyushenkov, M. Abliz, K.D. Boerste, T.W. Buffington, C.L. Doose, J.D. Fuerst, Q.B. Hasse, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D. Skiadopoulos, E. Trakhtenberg, I. Vasserman
    ANL, Argonne, USA
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Superconducting technology offers the possibility of building short-period undulators for synchrotron light sources. Such undulators will deliver higher fluxes at higher photon energies to the light source user community. The Advanced Photon Source (APS) team is building the first superconducting planar undulator to be installed in the APS storage ring. The current status of the project is presented in this paper.
Hard X-ray Self-seeding at the Linac Coherent Light Source  
  • P. Emma, J.W. Amann, F.-J. Decker, Y.T. Ding, Y. Feng, J.C. Frisch, D. Fritz, J.B. Hastings, Z. Huang, J. Krzywinski, H. Loos, A.A. Lutman, H.-D. Nuhn, D.F. Ratner, J.A. Rzepiela, S. Spampinati, D.R. Walz, J.J. Welch, J. Wu, D. Zhu
    SLAC, Menlo Park, California, USA
  • W. Berg, R.R. Lindberg, D. Shu, Yu. Shvyd'ko, S. Stoupin, E. Trakhtenberg, A. Zholents
    ANL, Argonne, USA
  • V.D. Blank, S. Terentiev
    TISNCM, Troitsk, Russia
  Funding: Work supported by US Department of Energy, contract number DE-AC02-76SF00515.
We report on experimental results of FEL self-seeding with Angstrom wavelengths at the Linac Coherent Light Source (LCLS) at SLAC. The scheme, suggested at DESY*, replaces the 16th 4-m long undulator segment (out of 33 total) with a weak magnetic chicane and a diamond-based monochromator in Bragg transmission geometry. The monochromatized SASE FEL pulse from the first half of the undulator line then seeds the second half. This demonstration of hard x-ray self-seeding is shown to narrow the FEL bandwidth by a factor 40-50, allows longitudinally coherent x-ray pulses near the Fourier-transform limit, and may eventually allow an increases in peak brightness by 1-2 orders of magnitude after applying an aggressive undulator field taper.
* G. Geloni, V. Kocharyan, E. Saldin, DESY 10-133, Aug. 2010.
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