Author: De Ninno, G.
Paper Title Page
TUOA04
 Coherence Properties of FERMI@Elettra  
 
  • B. Mahieu, E. Allaria, G. De Ninno, E. Ferrari, F. Parmigiani, L. Raimondi, S. Spampinati, C. Spezzani, C. Svetina, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • B. Mahieu
    CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
  
  We report the results of a campaign of measurements aimed at characterizing the spatial and temporal coherence of the FERMI@Elettra free-electron laser. The results (the first obtained on a high-gain seeded single-pass free-electron laser), are compared with those obtained on other (SASE-based) facilities.  
slides icon Slides TUOA04 [3.274 MB]  
 
TUPD17 Seeding of SPARC-FEL with a Tunable Fibre-based Source 269
 
  • N.Y. Joly
    University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany
  • S. Bielawski
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • W. Chang, P. Hölzer, K. Mak, P.St.J. Russell, F. Tani, J.C. Travers
    Max Planck Institute for the Science of Light, Erlangen, Germany
  • F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • M.-E. Couprie, M. Labat, T. Tanikawa
    SOLEIL, Gif-sur-Yvette, France
  • G. De Ninno, B. Mahieu
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. Gatti
    INFN/LNF, Frascati (Roma), Italy
  • V. Petrillo
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • J.V. Rau
    ISM-CNR, Rome, Italy
  
  Instead of seeding a free electron laser in the UV-VUV with a frequency doubled or tripled laser or high order harmonics, here we investigate and present the first results on seeding SPARC-FEL with a fiber-based tunable ultraviolet source. The seed generation system consists of a kagomé hollow-core photonic crystal fiber filled with noble gas. Diffraction-limited DUV pulses of >50 nJ and fs-duration which are continuously tunable from below 200 nm to above 300 nm are generated. The process is based on soliton-effect self-compression of the pump pulse down to a few optical cycles, accompanied by the emission of a resonant dispersive wave in the DUV spectral region. The quality of the compression highly depends on the pump pulse duration, and ideally, pulses <60 fs should be used. Our experimental set-up and associated GENESIS simulations enable us to study the utility of the seed tunability, and the influence of the seed quality, on the performance of the SPARC-FEL in the 200-300 nm range.  
 
WEPD20 Time-Sliced Emittance and Energy Spread Measurements at FERMI@Elettra 417
 
  • G. Penco, E. Allaria, P. Craievich, G. De Ninno, S. Di Mitri, W.M. Fawley, E. Ferrari, L. Giannessi, C. Spezzani, M. Trovò
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • S. Spampinati
    SLAC, Menlo Park, California, USA
  
  FERMI@Elettra is a single pass seeded FEL based on the high gain harmonic generation scheme, producing intense photon pulses at short wavelengths. For that, a high-brightness electron beam is required, with a small uncorrelated energy spread. In this paper, we present a detailed campaign of measurements aimed at characterizing the electron-beam time-sliced emittance and energy spread, both after the first magnetic compressor and at the end of the linac.  
 
FROBI01
 Towards Compact Short FEL Sources : Seeding and LWFA based FEL  
 
  • M. Labat, M.-E. Couprie, A. Loulergue
    SOLEIL, Gif-sur-Yvette, France
  • S. Bielawski
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • G. De Ninno
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • N.Y. Joly
    University of Erlangen-Nuremberg, Erlangen-Nuremberg, Germany
  • P.St.J. Russell
    Max Planck Institute for the Science of Light, Erlangen, Germany
  
  The seeding technique, proposed to improve the FEL temporal coherence and to enable more compact schemes, progressed significantly during this last decade. After conventionnal laser sources, eventually doubled or tripled in crystal, high order harmonics generated in gas were successfully used, bringing FELs in the XUV range. We are now involved in the demonstration of a new scheme, using fiber based tunable ultraviolet source. Its output power and tunability are of high interest. Last results obtained with the MaxPlanck Institute and the SPARC teams are presented. Seeding can lead to complex dynamics between the electron and the light pulse. Numerical studies revealed possible pulse splitting effects. We will report on their possible observation in collaboration with the FERMI team. Future FELs may also rely on emerging accelerators generated by laser wakefiled acceleration. Recently, the LUNEX5 project was proposed in France. It consists in one undulator line, fed by either a conventionnal LINAC or a laser wakefield accelerator (LWFA), to deliver XUV fs pulses to pilot user experiments. Preliminary work on radiation optimization of an FEL based on a LWFA will be also presented.  
 
MOOB06 First Lasing of FERMI FEL-2 (1° Stage) and FERMI FEL-1 Recent Results 13
 
  • L. Giannessi, E. Allaria, L. Badano, D. Castronovo, P. Cinquegrana, P. Craievich, G. D'Auria, M.B. Danailov, A.A. Demidovich, S. Di Mitri, B. Diviacco, W.M. Fawley, E. Ferrari, L. Fröhlich, G. Gaio, R. Ivanov, E. Karantzoulis, B. Mahieu, N. Mahne, I. Nikolov, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, M. Veronese, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. De Ninno
    University of Nova Gorica, Nova Gorica, Slovenia
  • F. Parmigiani
    Università degli Studi di Trieste, Trieste, Italy
  
  The FERMI@Elettra seeded Free Electron Laser (FEL) is based on two complementary FEL lines, FEL-1 and FEL-2. FEL-1 is a single stage cascaded FEL delivering light in the 80-20nm wavelength range, while FEL-2 is a double stage cascaded FEL where the additional stage should extend the frequency up-conversion to the spectral range of 20-4nm. The FEL-1 beam line is in operation since the end of 2010, with user experiments carried on in 2011 and 2012. During 2012 the commissioning of the FEL-2 beam line has started and the first observation of coherent light from the first stage of the cascade has been demonstrated. In the meanwhile the commissioning of a number of key components of FERMI, as the laser heater, the X-Band cavity for the longitudinal phase space linearization and the high energy RF deflector has been completed. The additional control on the longitudinal phase space and a progressive improvement in the machine optics optimization had a significant impact of FEL-1 performances, which has reached the expected specifications. In addition, emission of radiation at very high order conversion factors (up to 29th) has been observed and double stage cascades have been preliminarily tested with the observation of coherent radiation in the water window, up to the 65th harmonic of the seed laser, at about 4 nm.  
slides icon Slides MOOB06 [6.633 MB]  
 
MOPD58 Commissioning of the FERMI@ELETTRA Laser Heater 177
 
  • S. Spampinati, E. Allaria, L. Badano, S. Bassanese, D. Castronovo, M.B. Danailov, A.A. Demidovich, S. Di Mitri, B. Diviacco, W.M. Fawley, L. Giannessi, G. Penco, C. Spezzani, M. Trovò
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. De Ninno, E. Ferrari
    University of Nova Gorica, Nova Gorica, Slovenia
  
  The linac of the FERMI seeded free electron laser includes a laser heater to control the longitudinal microbunching instability, which otherwise is expected to degrade the quality of high brightness electron beam sufficiently to reduce the FEL power. The laser heater consists of an short undulator located in a small magnetic chicane through which an external laser pulse enters to the electron beam both temporally and spatially. The resulting interaction within the undulator produces an energy modulation of the electron beam on the scale of the optical wavelength. This modulation together with the effective R52 transport term of the chicane increases the incoherent energy spread (i.e., e-beam heating). We present the first commissioning results of this system and its impact on the electron density and energy distribution and on FEL output quality.  
 
TUOB02 Spectral Characterization of the FERMI Pulses in the Presence of Electron-beam Phase-space Modulations 213
 
  • E. Allaria, S. Di Mitri, W.M. Fawley, E. Ferrari, L. Fröhlich, L. Giannessi, B. Mahieu, G. Penco, C. Spezzani, M. Trovò
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. De Ninno, S. Spampinati
    University of Nova Gorica, Nova Gorica, Slovenia
  
  As a seeded FEL based on a single stage HGHG configuration, FERMI's FEL-1 has produced very narrow bandwidth FEL pulses in the XUV wavelength region relative to those typical of SASE devices. This important feature of seeded FELs relies however upon the capability to produce high quality electron beams and with clean longitudinal phase spaces. As has been predicted previously, the FEL output spectra can be modified from a simple, nearly transform-limited single spike by modulation and distortions of the longitudinal phase space of the electron beam. In this work we report a study of the FEL spectra recorded at FERMI for various situations showing the effects of phase-space modulation on the FEL properties.  
slides icon Slides TUOB02 [4.376 MB]