• 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, M. Cornacchia, P. Craievich, G. Penco
  ELETTRA, Basovizza
• S. Spampinati
  University of Nova Gorica, Nova Gorica
• M. Venturini, A. Zholents
  LBNL, Berkeley, California

Two machine configurations of the electron beam dynamics in the FERMI@elettra linac have been investigated, namely the one-stage and the two-stage electron bunch compression. One of the merits of the one-stage compression is that of minimizing the impact of the microbunching instability on the slice energy spread and peak current fluctuations at the end of the linac. Special attention is given to the manipulation of the longitudinal phase space, which is strongly influenced by the linac structural wake fields. The electron bunch with a ramping peak current is used in order to obtain, at the end of the linac, an electron bunch characterized by a flat peak current profile and a flat energy distribution. Effects of various jitters on electron bunch energy, arrival time and peak current are compared and relevant tolerances are obtained.