• S. Di Mitri, E. Allaria, R. Appio, L. Badano, D. Castronovo, M. Cornacchia, P. Craievich, S. Ferry, L. Froehlich, S.V. Milton, G. Penco, C. Scafuri, C. Spezzani, M. Trovò, M. Veronese
  ELETTRA, Basovizza
• R. Bartolini
  Diamond, Oxfordshire
• G. De Ninno, S. Spampinati
  University of Nova Gorica, Nova Gorica
• P. Evtushenko
  JLAB, Newport News, Virginia
• W.M. Fawley
  LBNL, Berkeley, California
• L. Giannessi
  ENEA C.R. Frascati, Frascati (Roma)
• A.A. Lutman
  DEEI, Trieste
• M. Sjöström
  MAX-lab, Lund

Some experiences have recently been collected from the FERMI@elettra Free Electron Laser first bunch compressor area. This includes a magnetic compressor, diagnostics for the characterization of the longitudinal and transverse phase space and suitable optics for matching to the downstream part of the linac. We report on the beam dynamics investigations in comparison with the modeling as well as the high level software control that has allowed this experience.

• S. Di Mitri, S. Ferry
  ELETTRA, Basovizza

Horizontal scraping, geometric and energy collimation of the Fermi@elettra electron beam has been investigated analytically and with the elegant particle tracking code. Beam scraping in the first magnetic bunch length compressor has been characterized in terms of reduction of the transverse emittance and variation of the energy chirp induced by the succeeding linac longitudinal wake field. The locations of the geometric and energy collimators have been identified in the machine lattice. A novel definition of collimation efficiency is proposed that allowed us to identify a configuration of the collimation system that is a compromise between the collimation performance, optics design and available space.