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Title: Theoretical and experimental analysis of a linear accelerator endowed with single feed coupler with movable short-circuit

The front-end injection systems of the FERMI@Elettra linac produce high brightness electron beams that define the performance of the Free Electron Laser. The photoinjector mainly consists of the radiofrequency (rf) gun and of two S-band rf structures which accelerate the beam. Accelerating structures endowed with a single feed coupler cause deflection and degradation of the electron beam properties, due to the asymmetry of the electromagnetic field. In this paper, a new type of single feed structure with movable short-circuit is proposed. It has the advantage of having only one waveguide input, but we propose a novel design where the dipolar component is reduced. Moreover, the racetrack geometry allows to reduce the quadrupolar component. This paper presents the microwave design and the analysis of the particle motion inside the linac. A prototype has been machined at the Elettra facility to verify the new coupler design and the rf field has been measured by adopting the bead-pull method. The results are here presented, showing good agreement with the expectations.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4]
  1. Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Trieste (Italy)
  2. (Italy)
  3. (Paul Scherrer Institute), Villigen (Switzerland)
  4. Department of Engineering and Architecture, University of Trieste, Trieste (Italy)
Publication Date:
OSTI Identifier:
22220330
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 84; Journal Issue: 11; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ASYMMETRY; DESIGN; ELECTRICAL FAULTS; ELECTROMAGNETIC FIELDS; ELECTRON BEAMS; FREE ELECTRON LASERS; GEOMETRY; LINEAR ACCELERATORS; MICROWAVE RADIATION; PERFORMANCE; RADIOWAVE RADIATION; RF SYSTEMS; WAVEGUIDES