Author: Krejcik, P.
Paper Title Page
MOPGF014 LLRF Controls Upgrade for the LCLS XTCAV project at SLAC 1
 
  • S. Condamoor, Y. Ding, P. Krejcik, H. Loos, T.J. Maxwell, J.J. Olsen
    SLAC, Menlo Park, California, USA
 
  Funding: This work was performed in support of the LCLS project at SLAC. Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
SLAC's Low Level Radio Frequency (LLRF) controls software for the S-Band deflecting structures needed to be upgraded significantly when a new X-Band transverse deflecting cavity (XTCAV) was installed downstream of the LCLS undulators in Spring 2013 to assist in FEL diagnostics such as characterizing the temporal profile of X-ray pulses that vary shot-to-shot. The unique location of the XTCAV in the beamline posed several challenges. A new design of the Modulator and Klystron control Support Unit (MKSU-II) for interlocking was added at the XTCAV controls station that required new software development. The timing setup was also different from the rest of the Linac. This paper outlines the LLRF controls layout for the XTCAV and discusses the manner in which the challenges were addressed. XTCAV has now become a successful tool for gathering data that enables reconstruction of X-ray FEL power profiles with greater resolution.
SLAC Publication Number: SLAC-PUB-16414
 
poster icon Poster MOPGF014 [3.646 MB]  
 
MOPGF015 Fast Wire Scanner Upgrade for LCLS 1
 
  • J.M. D'Ewart, M.L. Campell, P. Krejcik, H. Loos, K. Luchini
    SLAC, Menlo Park, California, USA
 
  Wire scanners are a main diagnostic tool for transverse beam size and emittance measurements at LCLS. The original SLAC wire scanners were not optimized for speed (taking minutes to scan), and can't perform at the desired level of position resolution necessary for measuring LCLS' small beam size. A new fast wire scanner, based on a dc linear servo motor, has been designed and installed in the LCLS. The new fast wire scanner has several advantages over the original wire scanner: scan times are reduced from minutes to seconds while minimizing wire vibrations. Rather than counting open-loop step pulses, the new fast wire scanner uses real time position capture for beam synchronous sampling of the wire position, enhancing beam profile accuracy.