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Di Mitri, S.

 
Paper Title Page
MOPCH019 Baseline Design of the Linac Upgrade for Fermi 92
 
  • G. D'Auria, P. Craievich, P. Delgiusto, S. Di Mitri, M. Ferianis, M.M. Milloch, G.C. Pappas, G. Penco, M. Trovo
    ELETTRA, Basovizza, Trieste
  • L.R. Doolittle, A. Ratti
    LBNL, Berkeley, California
  
  The FERMI FEL requires a major upgrade of the existing linac, which needs to be transformed from being the injector for the ELETTRA light source, to becoming the source for the FERMI FEL. In this work, we present the baseline design, including the integration of the 7 additional systems from the LIL linac, and one X-band station as linearizers. We will present the new layout with the required modifications and additions to the existing infrastructure to meet the more demanding needs of the system. Such modifications include a new RF controller, improvements in the modulator stability and an upgrade to the average power capabilities of the system to operate at 50 Hz. Test results from the characterization of the existing systems will be included, as well as plans for future development.  
MOPCH021 FERMI @ Elettra: Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays 0
 
  • C.J. Bocchetta, E. Allaria, D. Bulfone, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, M. Ferianis, A. Gambitta, A. Gomezel, E. Karantzoulis, G. Penco, M. Trovo
    ELETTRA, Basovizza, Trieste
  • J.N. Corlett, W.M. Fawley, S.M. Lidia, G. Penn, A. Ratti, J.W. Staples, R.B. Wilcox, A. Zholents
    LBNL, Berkeley, California
  • M. Cornacchia, P. Emma
    SLAC, Menlo Park, California
  • W. Graves, F.O. Ilday, F.X. Kaertner, D. Wang
    MIT, Middleton, Massachusetts
  • F. Parmigiani
    Università Cattolica-Brescia, Brescia
  
  We present a summary of the conceptual design for the FERMI FEL project funded for construction at the Sincrotrone Trieste, Italy. The project will be the first user facility based on seeded harmonic cascade FEL's, providing controlled, high peak-power pulses, and complementing the storage ring light source at Sincrotrone Trieste. The facility is to be driven by electron beam from a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac. Designed for an initial complement of two FEL's, providing tunable output over a range from ~100 nm to ~10 nm, FERMI will allow control of pulse duration from less than 100 fs to approximately1 ps, and with polarization control from APPLE undulator radiators. Seeded by tunable UV lasers, FEL-1 is a single-stage of harmonic generation to operate over ~100 nm to ~40 nm, and FEL-2 a two-stage cascade operating from ~40 nm to ~10 nm or shorter wavelength. Photon output is spatially and temporally coherent, with peak power in the 100’s MW to GW range. We have designed FEL-2 to minimize the output radiation spectral bandwidth. Major systems and overal facility layout are described, and key performance parameters summarized.  
MOPCH047 Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac 145
 
  • M. Cornacchia, P. Craievich, S. Di Mitri
    ELETTRA, Basovizza, Trieste
  • I.V. Pogorelov, J. Qiang, M. Venturini, A. Zholents
    LBNL, Berkeley, California
  • D. Wang
    MIT, Middleton, Massachusetts
  • R.L. Warnock
    SLAC, Menlo Park, California
  
  A study of the electron beam dynamics in the linac is made within the framework of the design of a free electron laser (FEL) at the Syncrotrone Trieste*. A scope of the work includes analysis of two operational scenarios, one with relatively long electron bunches of the order of 1.5 ps and a moderate peak current of 500 A and one with shorter bunches of the order of 0.7 ps and higher peak current of the order of 800 A. In both cases, care has been taken to preserve the slice and projected emittances formed in the photocathode gun injector and to minimize the slice energy spread. The latter goal is accomplished by balancing the onset of the microbunching instability driven by the longitudinal space charge forces and the emission of coherent synchrotron radiation using Landau damping produced by a so-called laser heater. Various analytical techniques and tracking codes have been employed to obtain the reported results.

*C. Bocchetta, et al., this conference.

 
WEPCH077 Particle Tracking in a Sextupole Field using the Euler Method Approximation 2098
 
  • S. Di Mitri, E. Karantzoulis
    ELETTRA, Basovizza, Trieste
  
  The purpose of this paper is to evaluate any differences in the single particle tracking through a magnetic lattice when sextupoles are treated either like sliced or single-kick elements. Only on-energy transverse motion is considered. Convergence and symplecticity of the method of sliced sextupoles are discussed. Dynamic apertures and transverse phase spaces applied to the Elettra synchrotron lattice are compared for the two cases.  
THOPA01 Formation of Electron Bunches for Harmonic Cascade X-ray Free Electron Lasers 2738
 
  • M. Cornacchia, S. Di Mitri, G. Penco
    ELETTRA, Basovizza, Trieste
  • A. Zholents
    LBNL, Berkeley, California
  
  A relatively long electron bunch is required for an operation of harmonic cascade free electron lasers (FELs). This is because they repeatedly employ a principle when the radiation produced in one cascade by one group of electrons proceeds ahead and interacts with other electrons from the same electron bunch in the next cascade. An optical laser is used to seed the radiation in the first cascade. Understandably the length of the electron bunch in this situation must accommodate the length of the x-ray pulse multiplied by a number of cascades plus a time jitter between the arrival time of the electron bunch and a seed laser pulse. Thus a variation of the peak current along the electron bunch as well as slice energy spread and emittance may affect the performance of the FEL. In this paper we analyze all possible sources affecting the distributions and interplay between them and show how desirable distributions can be produced. Results are illustrated with simulations using particle tracking codes.  
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THPCH043 Jitter Studies for the FERMI@ELETTRA Linac 2880
 
  • P. Craievich, S. Di Mitri
    ELETTRA, Basovizza, Trieste
  • A. Zholents
    LBNL, Berkeley, California
  
  The FEL project FERMI@ELETTRA* will use the existing linac upgraded to 1.2GeV to produce photon pulses in the wavelength range between 100-10 nm by means of harmonic generation in a seeded scheme. FEL operations foresee stringent requirements for the stability of the global linac output parameters, such as the electron bunch arrival time, peak current, average energy and the slice electron bunch parameters, such as the slice peak current and slice average energy. In order to understand the sensitivity of these parameters to jitters of various error sources along the linac an elaborate study using tracking codes has been performed. As a result, we created a tolerance budget to be used as guidance in the design of the linac upgrade. In this paper we give a detailed description of the applied procedures and present the obtained results.

*C. Bocchetta et al. "FERMI@ELETTRA - Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays", this conference.

 
THPCH044 Beam Break-up Instability in the FERMI@ELETTRA Linac 2883
 
  • S. Di Mitri, P. Craievich
    ELETTRA, Basovizza, Trieste
  
  The beam break-up instability is studied for the 1.2 GeV linac of FERMI @ ELETTRA FEL*. This instability is driven by transverse wake fields acting on an electron beam travelling off-axis in the accelerating structures due to the launching errors in positions, angles, energy and misalignment of various lattice elements. Two operational scenarios are considered: one with a relatively long electron bunch of 1.5 ps and a moderate peak current of 500 A and one with a shorter bunch of 0.7 ps and a higher peak current of 800 A. Attention is given to the correction of the "banana" shape of the electron bunch caused by the instability. The simulation results are compared with the analytical predictions.

*C. Bocchetta et al. “FERMI@Elettra – Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays”, this conference.

 
THPLS033 Elettra New Full Energy Injector Status Report 3356
 
  • M. Svandrlik, S. Bassanese, F.C. Cargnello, A. Carniel, K. Casarin, D. Castronovo, P. Craievich, G. D'Auria, R. De Monte, S. Di Mitri, A. Fabris, R. Fabris, M. Ferianis, A. Gambitta, F. Giacuzzo, M. Giannini, F. Iazzourene, G.L. Loda, M. Lonza, F.M. Mazzolini, D.M. Morelli, G. Pangon, C. Pasotti, G. Penco, L.P. Pivetta, L. Rumiz, C. Scafuri, G. Tromba, A. Vascotto, R. Visintini, D. Zangrando
    ELETTRA, Basovizza, Trieste
  
  The Elettra new full energy injector will be based on a 100 MeV linac pre-injector, a 2.5 GeV booster synchrotron and two new beam transfer lines. It will replace the existing 1.2 GeV linac injector and transfer line. Full funding was finally available in 2005, which allowed to start, or in some cases to re-start, the construction activities. The status of the project will be presented in this paper, in particular the progress of the fabrication of various components, like magnets, power supplies, vacuum chambers; also the status of the construction of the building and technical plants will be given. Results of recent optimization studies will also be outlined. The commissioning of the new injector is scheduled to start in Spring 2007, while the first ELETTRA operation for user's with the new full energy injector is expected for the last quarter of 2007.