Coherent OTR as a tool for transverse bunch size measurements

Sep 16, 2019, 12:40 PM
Oral General radiation properties from relativistic particles General Properties of Radiation from Relativistic Particles


Artem Novokshonov (DESY)


Optical Transition Radiation (OTR) is widely used for transverse beam profile diagnostics at electron linear accelerators. But this technique may not be implemented for FEL’s [1] or LWPA accelerators [2], the reason is that such machines have ultrashort bunches causing coherent effects in the OTR emission process [3]. An approach to calculate the coherent OTR (COTR) propagation through a standard optical system with a focusing lens has been developed. COTR image of the bunch profile is obtained by the summation of the OTR fields coherently emitted by all electrons from a bunch and then focused in the detector plane. Assuming the bunch transverse profile is a Gaussian type it was shown that the final image has a typical “ring” shape. The characteristics of such image depend on the bunch transverse size and can be determined from the COTR image measurement for known optical system parameters.
[1] E. Saldin, E. Schneidmiller, M. Yurkov, The Physics of Free Electron Lasers // Springer-Verlag, 2010.
[2] N. Bourgeois, et al., Transverse Beam Profile Measurements of Laser Accelerated Electrons using Coherent Optical Radiation // AIP Conf. Proc., 1507, (2012) 258.
[3] H. Loos, R. Akre, et al., Observation of Coherent Optical Transition Radiation in the LCLS Linac // SLAC-PUB-13395 (2008).

This work was supported by the grant of the Russian Ministry of Science # 3/1903.2017.

Primary authors

Alexander Potylitsyn (Tomsk polytechnic university) Mr T. Gusvitskii (Tomsk Polytechnic University) Leonid Sukhikh (Tomsk Polytechnic University) Gero Kube (DESY) Artem Novokshonov (DESY)

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