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.