Development of a combined transition and diffraction radiation station for non-invasive beam size monitoring on linear accelerators

Michele Bergamaschi

Research output: ThesisDoctoral Thesis

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Next generation linear colliders such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC) will accelerate particle beams with extremely small emittance. The high current and small size of the beam (micron-scale) due to such a small emittance require non-invasive, high-resolution techniques for beam diagnostics. Diffraction Radiation (DR), a polarization radiation that appears when a charged particle moves in the vicinity of a medium, is a promising candidate as it is non-invasive. Despite these advantages DR is used less than other techniques mainly due to a challenging target fabrication (micrometer scale slits production) and data extraction. The aim of this thesis is devoted to study the feasibility of an instrument based on DR and the limitation of this technique applied to high energy linear accelerators. Since DR is sensitive to beam parameters other than the transverse profile (e.g. its divergence and position), preparatory simulations have been performed with realistic beam parameters. A new dedicated instrument has been designed, installed and commissioned in the KEK Accelerator Test Facility (ATF2) beam line. At present DR has been observed in the visible wavelength range and in the ultraviolet (down to 250 nm) to optimize sensitivity to small beam sizes. Presented here are the latest results of these DR beam size measurements and simulations showing that this technique allows beams as small as a few microns to be measured.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Karataev, Pavel, Supervisor
  • Mazzoni, Stefano, Supervisor, External person
Award date1 Jun 2019
Publication statusUnpublished - 2018


  • UV
  • visible
  • ATF
  • KEK
  • CERN
  • transition radiation interference
  • electromagnetic shadowing
  • particle accelerator
  • ATF2
  • beam size
  • non-invasive
  • non interceptive beam size measurements
  • beam instrumentation
  • beam diagnostics
  • beam emittance
  • transverse beam size
  • Linear Accelerator
  • CLIC
  • ILC

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