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Rule, D. W.

Paper Title Page
FRPMN112 Far-Field OTR and ODR Images Produced by 7-GeV Electron Beams at APS 4372
 
  • A. H. Lumpkin, W. Berg, N. Sereno, B. X. Yang, C. Yao
    ANL, Argonne, Illinois
  • D. W. Rule
    NSWC, West Bethesda, Maryland
  
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357

We have investigated the angular distribution patterns (far-field focus) of optical transition radiation (OTR) and optical diffraction radiation (ODR) generated by 7-GeV electron beams passing through and near an Al metal plane, respectively. The 70-μrad opening angles of the OTR patterns provide calibration factors for the system. Effects of the upstream quadrupole focusing strength on the patterns as well as polarization effects were observed. The OTR data are compared to an existing OTR single-foil model, while ODR profile results are compared to expressions for single-edge diffraction. ODR was studied with impact parameters of about 1.25 mm, close to the gamma λ?bar value of 1.4 mm for 628-nm radiation. We expect angle-pointing information along the x axis parallel to the mirror edge is available from the single-lobe ODR data as well as divergence information at the sub-100-μrad level. Experimental and model results will be presented.

 
FRPMS001 Numerical Simulation of Optical Diffraction Radiation from a 7-GeV Beam 3850
 
  • C. Yao, A. H. Lumpkin
    ANL, Argonne, Illinois
  • D. W. Rule
    NSWC, West Bethesda, Maryland
  
  Funding: Work supported by U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Interest in nonintercepting (NI) beam size monitoring for top-up operations at the Advanced Photon Source (APS) motivated our investigations of optical diffraction radiation (ODR) techniques. We have reported our experiment results earlier. In particular, we wanted to monitor the beam size in the booster-to-storage ring (BTS) transport line using near-field ODR. An analytical model was numerically evaluated for the APS BTS beam size cases. In addition, the simulations show that near-field ODR profiles have sensitivity to beam size in the 20- to 50-μm region, which are relevant to X-ray FELs and the international linear collider (ILC). The simulation indicates that the orthogonal polarization component is close to a Gaussian distribution and more sensitive to beam size variations, and therefore is more suitable for beam size measurement. Under some circumstances the parallel polarization component shows a non-Gaussian distribution that is also beam size dependent. This report describes the simulation method, the results, and the comparison with experiment results.