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Berg, 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.

FRPMN118 LCLS-S1 Optical Transition Radiation Monitor 4396
  • W. Berg, L. Erwin, S. E. Shoaf, B. X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by the U. S. Department of Energy, under Contract Nos. DE-AC02-06CH11357 and DE-AC03-76SF00515.

ANL has developed a high-resolution optical transition radiation (OTR) imaging monitor system for the LCLS injection linac at SLAC. The imaging station, OTR-S1, will be located at the S1 spectrometer with a beam energy of 135 MeV. The system will be used to acquire 2-D transverse beam distributions of the accelerated photocathode-gun-generated electron beam. We anticipate an average beam current of 0.2-1 nC and nominal beam spot size of σ-x 130 microns, σ-y 100 microns. The imaging system was designed for a field of view h/v: 10x7.5 mm. The spatial resolution of ~12 microns was verified over the central 5x4 mm region in the visible. A 12-bit digital camera acquires the image and a Mac-based digital frame capturing system was employed for the initial lab-based performance testing of the device. We are reporting on system development, image capture system, testing methodology, and test data analysis. Commissioning results will be reported as they become available.