Author: Ratner, D.F.
Paper Title Page
TUB03 FEL Overcompression in the LCLS 337
  • J.L. Turner, F.-J. Decker, Y. Ding, Z. Huang, R.H. Iverson, J. Krzywinski, H. Loos, A. Marinelli, T.J. Maxwell, H.-D. Nuhn, D.F. Ratner, T.J. Smith, J.J. Welch, F. Zhou
    SLAC, Menlo Park, California, USA
  Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515
Overcompression of the Linac Coherent Light Source (LCLS) x-ray Free Electron Laser (FEL) at the SLAC National Accelerator Center is studied. The studies and operational implications are summarized in this talk.
slides icon Slides TUB03 [4.493 MB]  
TUP035 Investigation of Reverse Taper to Optimize the Degree of Polarization for the Delta Undulator at the LCLS 465
  • J.P. MacArthur
    Stanford University, Stanford, California, USA
  • Z. Huang, A. Lutmann, A. Marinelli, T.J. Maxwell, H.-D. Nuhn, D.F. Ratner
    SLAC, Menlo Park, California, USA
  Funding: U.S. Department of Energy under contract No. DE-AC02-76SF00515
A 3.2 m adjustable phase Delta undulator* will soon be installed on the last girder of the LCLS undulator line. The Delta undulator will act as an afterburner terminating the 33 undulator line, providing arbitrary polarization control to users. Two important figures of merit for users will be the degree of polarization and the x-ray yield. In anticipation of this installation, machine development time at the LCLS was devoted to maximizing the final undulator x-ray contrast and yield with a standard canted pole undulator acting as a stand in for the Delta undulator. Following the recent suggestion** that a reverse taper (dK/dz > 0) in the main undulator line could suppress linearly polarized light generated before an afterburner while still producing the requisite microbunching, we report on a reverse taper study at the LCLS wherein a yield contrast of 15 was measured along the afterburner. We also present 1D simulations comparing the reverse taper technique to other schemes.
* Nuhn, H.-D., Anderson, S., Bowden, G., Ding, Y., Gassner, G., et al., (2013).
** Schneidmiller, E. A. and Yurkov, M. V., Phys. Rev. ST Accel. Beams 16, 110702 (2013).
Soft X-ray Self-seeding Setup and Results at LCLS  
  • D.F. Ratner, J.W. Amann, D.K. Bohler, M. Boyes, D. Cocco, F.-J. Decker, Y. Ding, D. Fairley, Y. Feng, J.B. Hastings, P.A. Heimann, Z. Huang, J. Krzywinski, H. Loos, A.A. Lutman, G. Marcus, A. Marinelli, T.J. Maxwell, S.P. Moeller, P.A. Montanez, D.S. Morton, H.-D. Nuhn, D.R. Walz, J.J. Welch, J. Wu
    SLAC, Menlo Park, California, USA
  • K. Chow, L.N. Rodes
    LBNL, Berkeley, California, USA
  • U. Flechsig
    PSI, Villigen PSI, Switzerland
  • S. Serkez
    DESY, Hamburg, Germany
  The soft X-ray self seeding program was designed to provide near transform-limited pulses in the range of 500 eV to 1000 eV. The project was a three-way collaboration between SLAC, Lawrence Berkeley National Lab, and the Paul Scherrer Institute in Switzerland. Installation finished in the Fall of 2013, and after the early stages of commissioning we have measured up to 0.5mJ pulse energy and resolving powers of up to 5000 across the design wavelength range, representing a several-fold increase in the brightness compared to the normal LCLS operating mode. Future work will aim to increase the total pulse energy and establish self-seeding as a robust user operation mode.  
slides icon Slides TUC02 [10.464 MB]