Author: Fawley, W.M.
Paper Title Page
MOD04 Status and Perspectives of the FERMI FEL Facility 1
  • L. Giannessi, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, F. Cilento, P. Cinquegrana, M. Coreno, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, F. Iazzourene, S. Krecic, M. Lonza, N. Mahne, M. Malvestuto, C. Masciovecchio, M. Milloch, N.S. Mirian, F. Parmigiani, G. Penco, A. Perucchi, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  FERMI is the seeded Free Electron Laser (FEL) user facility at the Elettra laboratory in Trieste, operating in the VUV to EUV and soft X-rays spectral range; the radiation produced by the seeded FEL is characterised by a number of desirable properties, such as wavelength stability, low temporal jitter and longitudinal coherence. In this paper, after an overview of the FELs performances, we will present the development plans under consideration for the next 3 to 5 years. These include an upgrade of the LINAC and of the existing FEL lines, the possibility to perform multi-pulse experiments in different configurations and an Echo Enabled Harmonic Generation experiment on FEL-2, the FEL line extending to 4 nm (310 eV).  
Towards the Demonstration of Soft X-Ray Echo-Enabled Harmonic Generation at Fermi  
  • E. Allaria, R. Bracco, D. Castronovo, I. Cudin, M.B. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, W.M. Fawley, M. Ferianis, L. Giannessi, M. Lonza, G. Penco, P. Rebernik Ribič, E. Roussel, S. Spampinati, C. Spezzani, L. Sturari, M. Svandrlik, M. Veronese, R. Visintini, M. Zaccaria, D. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • H.-H. Braun, E. Prat, S. Reiche
    PSI, Villigen PSI, Switzerland
  • G. De Ninno
    University of Nova Gorica, Nova Gorica, Slovenia
  • B.W. Garcia, J.B. Hastings, E. Hemsing, T.O. Raubenheimer, G. Stupakov, J.J. Welch
    SLAC, Menlo Park, California, USA
  • G. Penn
    LBNL, Berkeley, California, USA
  • E. Roussel
    SOLEIL, Gif-sur-Yvette, France
  • A. Zholents
    ANL, Argonne, Illinois, USA
  The echo-enabled harmonic generation seeding scheme is based on an echo mechanism that develops in the electron beam phase-space interacting with two seed lasers before and after a strong dispersive region. It has been proposed for extending the capabilities of externally seeded free electron lasers to reach short wavelengths. After the original proposal, a few experiments have confirmed the capabilities of efficient bunching generation at very high harmonics. However, up to now none of the experiments demonstrated FEL amplification from high harmonic bunching produced at 10 nm wavelengths or shorter. In this work, we report about our plans for performing an EEHG experiment at FERMI. The experiment will be done at the FEL-2 line normally operated in the double stage high-gain harmonic generation configuration in the wavelength range 20-4 nm. After the modification of a few hardware components planned for the first semester of 2018, the FEL-2 layout will be suitable for EEHG at wavelengths down to approximately 6 nm.  
High-Flux, Fully Coherent X-Ray FEL Oscillator  
  • K.-J. Kim, S.P. Kearney, T. Kolodziej, R.R. Lindberg, X. Shi, D. Shu, Yu. Shvyd'ko
    ANL, Argonne, Illinois, USA
  • K.L.F. Bane, Y. Ding, P. Emma, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell
    SLAC, Menlo Park, California, USA
  • V.D. Blank, S. Terentiev
    TISNCM, Troitsk, Russia
  • W.M. Fawley
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • C. Grizolli
    LNLS, Campinas, Brazil
  • W. Qin
    PKU, Beijing, People's Republic of China
  • S. Stoupin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J. Zemella
    DESY, Hamburg, Germany
  Funding: The ANL part of this work is supported by the U.S. DOE Office of Science under Contract No. DE-AC02-06CH11357 and the SLAC part under contract No. DE-AC02-76SF00515.
By optimizing the parameters of the accelerator, undulator, and the optical cavity, an XFELO driven by an 8-GeV superconducting linac is predicted to produce 10zEhNZeHn photons per pulse at the important photon energies around 14.4 keV.* This is an order of magnitude larger than that in previous designs.** With a BW of 3 meV (FWHM), rep rate of 1 MHz, and taking into account the full coherence, the spectral brightness is then 2×1026 photons per (mm2mr2 0.1\% BW), which is higher than any other source currently operating or anticipated in the future. Experiments at APS beam lines have shown that a high-quality diamond crystal can survive the power density (~15 kW/mm2) expected at the XFELO intra-cavity crystals preserving the high reflectivity.*** The compound refractive lenses can serve as the focusing element. Adding an XFELO to the suite of other FEL sources will, at a minor incremental cost but with a major scientific payoff, significantly expand the scientific capabilities at superconducting linac-based XFEL facilities, such as the European XFEL, the proposed LCLS-II High Energy upgrade and the XFEL project in Shanghai.
* W. Qin et al., this conference.
** R.R. Lindberg et al., Phys. Rev. ST Accel. Beams, vol 14, 403 (2011).
*** T. Kolodziej et al., this conference.
TUB01 Seeding Experiments and Seeding Options for LCLS II 1
  • E. Hemsing, R.N. Coffee, W.M. Fawley, Y. Feng, B.W. Garcia, J.B. Hastings, Z. Huang, G. Marcus, D.F. Ratner, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • G. Penn, R.W. Schoenlein
    LBNL, Berkeley, California, USA
  We discuss the present status of FEL seeding experiments toward the soft x-ray regime and on-going studies on possible seeding options for the high repetition soft x-ray line at LCLS-II. The seeding schemes include self-seeding, cascaded HGHG, and EEHG to reach the 1-2 nm regime with the highest possible brightness and minimal spectral pedestal. We describe relevant figures of merit, performance expectations, and potential issues.