THA —  FEL Technology (Undulators, Magnets, Photon Diagnostics and Beamlines)   (28-Aug-14   08:30—10:00)
Chair: K.I. Tiedtke, DESY, Hamburg, Germany
Paper Title Page
THA01 THz Streak Camera for FELTemporal Diagnostics: Concepts and Considerations 640
  • P.N. Juranic, R. Abela, I. Gorgisyan, C.P. Hauri, R. Ischebeck, B. Monoszlai, L. Patthey, C. Pradervand, M. Radovic, L. Rivkin, V. Schlott, A.G. Stepanov
    PSI, Villigen PSI, Switzerland
  • I. Gorgisyan, C.P. Hauri, L. Rivkin
    EPFL, Lausanne, Switzerland
  • R. Ivanov, P. Peier
    DESY, Hamburg, Germany
  • J. Liu
    XFEL. EU, Hamburg, Germany
  • B. Monoszlai
    University of Pecs, Pécs, Hungary
  • K. Ogawa, T. Togashi, M. Yabashi
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Owada
    JASRI/RIKEN, Hyogo, Japan
  The accurate, non-destructive measurements of FEL pulse length and arrival time relative to an experimental laser are necessary for operators and users alike. The FEL operators can get a better understanding of their machine and the optics of an FEL by examining the pulse length changes of the photons coming to the user stations, and the users can use the arrival time and pulse length information to better understand their data. PSI has created the pulse arrival and length monitor (PALM) based on the THz-streak camera concept for measurement at x-ray FELs, meant to be used at the upcoming SwissFEL facility. The first results from the experimental beamtime at SACLA will be presented, showcasing the accuracy and reliability of the device. Further plans for improvement and eventual integration into SwissFEL will also be presented.  
slides icon Slides THA01 [5.798 MB]  
THA02 Experimental Characterization of FEL Polarization Control with Cross Polarized Undulators 644
  • E. Ferrari, E. Allaria, G. De Ninno, B. Diviacco, D. Gauthier, L. Giannessi, G. Penco, C. Spezzani
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • J. Buck, M. Ilchen
    XFEL. EU, Hamburg, Germany
  • G. De Ninno, D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • Z. Huang, A.A. Lutman
    SLAC, Menlo Park, California, USA
  • G. Lambert, B. Mahieu
    LOA, Palaiseau, France
  • J. Viefhaus
    DESY, Hamburg, Germany
  Polarization control of the coherent radiation is becoming an important feature of recent and future short wavelength free electron laser facilities. While polarization tuning can be achieved taking advantage of specially designed undulators, a scheme based on two consecutive undulators emitting orthogonally polarized fields has also been proposed. Developed initially in synchrotron radiation sources, crossed polarized undulator schemes could benefit from the coherent emission that characterize FELs. In this work we report the first detailed experimental characterization of the polarization properties of an FEL operated with crossed polarized undulators in the Soft-X-Rays. Aspects concerning the average degree of polarization and the shot to shot stability are investigated together with a comparison of the performance of various schemes to control and switch the polarization  
slides icon Slides THA02 [5.383 MB]  
THA03 A Plan for the Development of Superconducting Undulator Prototypes for LCLS-II and Future FELs 649
  • P. Emma, N.R. Holtkamp, H.-D. Nuhn
    SLAC, Menlo Park, California, USA
  • D. Arbelaez, J.N. Corlett, S.A. Myers, S. Prestemon, D. Schlueter
    LBNL, Berkeley, California, USA
  • C.L. Doose, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, M. Kasa, G. Pile, E. Trakhtenberg
    ANL, Argonne, Ilinois, USA
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-76SF00515, DE-AC02-05CH11231, and DE-AC02-06CH11357.
Undulators serve as the primary source of radiation for modern storage rings, and more recently for the advent of Free-Electron Lasers (FELs). The performance of future FELs can be greatly enhanced using the much higher magnetic fields of superconducting undulators (SCU). For example, the LCLS-II hard x-ray undulator can be shortened by up to 70 m using an SCU in place of a PMU (permanent magnet undulator), or its spectral performance can be critically improved when using a similar length. In addition, SCUs are expected to be orders of magnitude less sensitive to radiation dose; a major issue at LCLS-II with its 1-MHz electron bunch rate. We present a funded R&D collaboration between SLAC, ANL, and LBNL, which aims to demonstrate the viability of superconducting undulators for FELs by building, testing, measuring, and tuning two 1.5-m long planar SCU prototypes using two different technologies: NbTi at ANL and Nb3Sn at LBNL. Our goal is to review and reassess the LCLS-II HXR baseline plans (PMU) in July of 2015, after the development and evaluation of both prototypes, possibly in favor of an SCU for LCLS-II.
slides icon Slides THA03 [29.468 MB]  
Optical Afterburner for Naturaly Synchronized Pump-probe Experiments at FLASH  
  • N. Stojanovic, A. Al-Shemmary, D. Espeloer, T. Golz, R. Riedel, E. Schneidmiller, M.V. Yurkov
    DESY, Hamburg, Germany
  • M. Foerst
    CFEL, Hamburg, Germany
  • M. Gensch
    HZDR, Dresden, Germany
  • F. Tavella
    HIJ, Jena, Germany
  Funding: German Federal Ministry for Education and Research, project 05K10CHC and 05K12CH4
We employ so- called Optical Afterburner [*,**] principle to generate optical replica pulses of X-ray pulse at FLASH (Free Electron LASer in Hamburg). These pulses are naturally synchronized to the FEL pulses and share the same envelope and arrival time, with accuracy down to few femtoseconds. Because of this, Optical Afterburner pulses can be used for complete temporal diagnostics for FEL pulses. Because we shift diagnostics challenge from X-ray to visible range, this significantly simplifies detection. During pulse- duration measurement campaigns at FLASH, Optical Afterburner has been demonstrated as versatile and accurate tool to measure pulse duration of X-ray FEL pulses. In the most recent development we have amplified, Optical Afterburner pulses by three orders of magnitude and will used it in the X-ray/Visible pump-probe experiments for ultimate temporal resolution. We have demonstrated amplification concept at FLASH, where we reach pulse energies above 1uJ at 1MHz repetition rate.
* E.L. Saldin, E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST Accel. Beams 13, 030701 (2010)
* Proceedings of IPAC2011, San Sebastián, Spain. THPC084