Author: Field, R.C.
Paper Title Page
MOP046 Undulator Radiation Damage Experience at LCLS 127
  • H.-D. Nuhn, R.C. Field, Yu.I. Levashov, X.S. Mao, M. Santana-Leitner, J.J. Welch, Z.R. Wolf
    SLAC, Menlo Park, California, USA
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515
The SLAC National Accelerator Laboratory has been running the Linac Coherent Light Source (LCLS), the first x-ray Free Electron Laser since 2009. Undulator magnet damage from radiation, produced by the electron beam traveling through the 133-m long straight vacuum tube, has been and is a concern. A damage measurement experiment has been performed in 2007 in order to obtain dose versus damage calibrations. Radiation reduction and detection devices have been integrated into the LCLS undulator system. The accumulated radiation dose rate was continuously monitored and recorded. In addition, undulator segments have been routinely removed from the beamline to be checked for magnetic (50 ppm, rms) and mechanic (about 0.25 μm, rms) changes. A reduction in strength of the undulator segments is being observed, at a level, which is now clearly above the noise. Recently, potential sources for the observed integrated radiation levels have been investigated. The paper discusses the results of these investigation as well as comparison between observed damage and measured dose accumulations and discusses, briefly, strategies for the new LCLS-II upgrade, which will be operating at more than 300 times larger beam rate.
MOP049 Oxygen Scintillation in the LCLS 137
  • J.L. Turner, R.C. Field
    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
Oxygen is tested as a replacement for Nitrogen in the Gas Detector system in the Linac Coherent Light Source (LCLS) x-ray Free Electron Laser (FEL) at the SLAC National Accelerator Center. The attenuation and energy monitors for LCLS use Nitrogen, but for experiments at the Nitrogen K 1S energy of about 410eV this functionality is gone due to energy fluctuations above and below the K-edge. Oxygen was tested as a scintillating gas at 400eV and 8.3keV.