Evidence for anomalous optical transition radiation linear polarization effects in beam-profile monitors

Abstract

Investigations of the effects of optical transition radiation (OTR) polarization components on beam profiles are presented. The transverse profiles are examined using the OTR perpendicular and parallel polarization components with respect to the dimension of interest. We observed $15% projected profile size reductions with the perpendicularly polarized components on a 65-m beam image size case at 14 MeV, a 150-m beam image size at 4.5 GeV, and a 1100-m beam image size at 7 GeV. These effects are all several times larger than expected (and anomalous in this sense) when compared to the standard OTR point-spread function calculations. We propose the time-averaged induced-current distribution which generates the OTR represents the actual beam size more faithfully with the perpendicular polarization component and recommend its routine use and subsequent deconvolution.

Coherent Optical Transition Radiation Imaging for Laser-Driven Plasma Accelerator Electron-Beam Diagnostics

“…The modeling of the OTR point spread function (PSF) [8][9][10][11][12] used in beam-size imaging and the OTR angular distribution [6,7,13] have been described previously. We will report the results of our modeling in the next section.…”

Accelerator Physics Center at Fermilab : History and Accomplishments (2007-2018)

“…The MDB setup finished operation in Jan. 2013 and will be re-used as IOTA proton injector in 2019. See References [85,86,94] in Appendix E. 5,11,24,28,31,35,36,51,69,102] in Appendix E.…”