Author: Poletto, L. P.
Paper Title Page
MOP019 Double-grating Monochromator for Ultrafast Free-electron Laser Beamlines 58
  • F. Frassetto, L. P. Poletto
    CNR-IFN, Padova, Italy
  • M. Kuhlmann, E. Plönjes
    DESY, Hamburg, Germany
  We present the design of an ultrafast monochromator explicitly designed for extreme-ultraviolet FEL sources, in particular the upcoming FLASH II at DESY. The design originates from the variable-line-spaced (VLS) grating monochromator by adding a second grating to compensate for the pulse-front tilt given by the first grating after the diffraction. The covered spectral range is 6-60 nm, the spectral resolution is in the range 1000–2000, while the residual temporal broadening is lower than 15 fs. The proposed design minimizes the number of optical elements, since just one grating is added with respect to a standard VLS monochromator and requires simple mechanical movements, since only rotations are needed to perform the spectral scan.  
MOP020 Compact Spectrometer for Single Shot X-ray Emission and Photon Diagnostics 62
  • F. Frassetto, P. Miotti, L. P. Poletto
    CNR-IFN, Padova, Italy
  • M. Coreno
    CNR-IMIP, Monterotondo Stazione RM, Italy
  • A. Di Cicco, F. Iesari
    Università di Camerino, Camerino, Italy
  • P. Finetti, E. Giangrisostomi, R. Mincigrucci, E. Principi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • C. Grazioli
    Universita Degli Studi di Trieste, Trieste, Italy
  • A. Kivimaki
    IOM-CNR, Trieste, Italy
  • S. Stagira
    CNR-IFN & Dipartimento di Fisica - Politecnico di Milano, Milano, Italy
  • S. Stagira
    Politecnico/Milano, Milano, Italy
  The design and characterization of a compact spectrometer realized for photon in-photon out experiments (in particular X-Ray Emission Spectroscopy), conceived to be used at the FERMI free-electron-laser (FEL) at ELETTRA (Italy) is here presented. The instrument can be easily installed on different end stations at variable distances from the target area both at synchrotron and FEL beamlines. Different input sections can be accommodated in order to fit the experimental requests. The design is compact in order to realize a portable instrument within an overall size of less than one square meter. The spectrometer covers the 25-800 eV spectral range, with spectral resolution better than 0.2%. The characterization on Gas Phase @ ELETTRA as instrument for XES and some experimental data of the FEL emission acquired at EIS-TIMEX @ FERMI, where the instrument has been used for photon beam diagnostics, are introduced.  
Chirped Pulse Amplification in a Seeded Free-electron Laser: Design of a Test Experiment at FERMI  
  • G. De Ninno, E. Allaria, I. Cudin, M.B. Danailov, A.A. Demidovich, S. Di Mitri, E. Ferrari, D. Gauthier, L. Giannessi, N. Mahne, G. Penco, L. Raimondi, P. Rebernik Ribič, C. Spezzani, L. Sturari, C. Svetina, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • H. Dacasa, B. Mahieu, P. Zeitoun
    LOA, Palaiseau, France
  • M. Fajardo
    IPFN, Lisbon, Portugal
  • E. Ferrari
    Università degli Studi di Trieste, Trieste, Italy
  • F. Frassetto, L. P. Poletto
    LUXOR, Padova, Italy
  • D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  In solid-state lasers, frequency chirping is employed to stretch a short pulse prior to amplification, mitigating the problems related to high power in the active medium. After amplification, the chirp is compensated in order to recover short pulse duration and, hence, high peak power. Chirped pulse amplification (CPA) in seeded FEL’s relies on a similar principle: the seed pulse is stretched in time before interacting with the electron beam. This permits one to create bunching on a larger number of electrons, and to (approximately) linearly increase the output energy of the generated FEL pulse. In ideal conditions, the chirp carried by the phase of the seed pulse is transmitted to the output phase of the FEL pulse. Chirp compensation after the last undulator allows production of a short (ideally Fourier-transformed) pulse and, therefore, a larger peak power with respect to what obtained, for the same conditions, in standard (i.e., no-chirp-on-the-seed) operation mode. In this paper, we present the preparatory studies (i.e., numerical simulations and compressor design), which have been carried out at FERMI, in view of performing the first test experiment of CPA on a seeded FEL.