• M. Lonza, S. Cleva, S. Di Mitri, O. Ferrando, G. Gaio, A.A. Lutman, G. Penco, L. Pivetta, G. Scalamera
  ELETTRA, Basovizza

FERMI@Elettra is a new 4th-generation light source based on a single pass free electron laser. It consists of a 1.5-GeV normal-conducting linac working at 50 Hz repetition rate and two chains of undulators where the photon beams are produced with a seeded laser multistage mechanism. A number of control loops, some of them working on a shot by shot basis, are required to stabilize the crucial parameters of the beams. For this purpose, a generalized real-time framework integrated in the control system has been designed to flexibly and easily implement feedback loops using several monitoring and control variables. The paper discusses the requirements of the control loops and the implementation of the feedback framework. The first closed loop results and the experience gained in the operation of the feedbacks during the first phase of the machine commissioning will also be presented.

• G. Penco, E. Allaria, L. Badano, S. Bassanese, M. Bossi, D. Castronovo, G. Ciani, S. Cleva, P. Craievich, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, S. Di Mitri, M. Ferianis, O. Ferrando, S. Ferry, L. Froehlich, G. Gaio, R. Ivanov, M. Lonza, A.A. Lutman, S.V. Milton, M. Petronio, M. Predonzani, F. Rossi, L. Rumiz, C. Scafuri, G. Scalamera, P. Sigalotti, S. Spampinati, C. Spezzani, M. Trovò, M. Veronese
  ELETTRA, Basovizza
• L. Pavlovič
  Uni LJ, Ljubljana

The FERMI@Elettra injector, comprised of a high-gradient, s-band, photo-cathode rf gun, the PC gun driven laser, the first two accelerating sections, controls, and suite of diagnostics has been commissioned in 2009. The electron beam has been characterized in terms of charge, energy, energy spread and transverse emittance, and results are provided in this paper. In early 2010 linac commissioning up to 250MeV continued, and by using the RF deflecting cavity, the slice parameters of the beam have been measured. Moreover, studies on the laser pulse shaping and the relative optimization of the longitudinal ramp profile required by the nominal bunch configuration are presented in this paper.

Slides

• G. Lanfranco, P. Craievich, D. La Civita, G.L. Loda, A.A. Lutman, F. Pradal, G. Sostero, M. Stefanutti
  ELETTRA, Basovizza
• M. Canetti, F. Gangini
  RIAL VACUUM S.p.A, Parma

The FERMI@Elettra project at the ELETTRA Laboratory of Sincrotrone Trieste (ST), currently under construction, will be comprised of a linear accelerator and two Free-Electron-Laser beamlines (FEL1, FEL2). In order to deliver high-intensity VUV and soft X-ray pulses, permanent magnet undulators with 9 mm minimum variable gap will be used. The adopted vacuum chambers will have a 7 by 25 mm² elliptical internal cross-section. While manufacturing the vacuum chamber in aluminum helps reducing the resistive wall wakefield effects, the chamber inner wall surface quality is strongly correlated to the surface roughness wakefield component. We report on the results of the study to improve the wall surface finish and lower the roughness periodicity. The chamber manufacturing status and its alignment mechanism is also presented.