• G. Lambert, M. Bougeard, W. Boutu, P. Breger, M.-E. Couprie, D. Garzella, H. Merdji, P. Monchicourt, P. Salieres
  CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette
• B. Carre
  CEA/Saclay, Gif-sur-Yvette
• T. Hara, H. Kitamura, T. Shintake
  RIKEN Spring-8 Harima, Hyogo

In order to reach very short wavelengths in FEL, and to have a more compact, fully coherent and tunable source, a particular seeding configuration is foreseen to be tested as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). The external source is the 13th harmonic (61.5 nm) of a Ti: Sa laser (25 mJ, 10 Hz, 100 fs) generated in 10 Hz pulsed Xe gas cell. The harmonic generation process provides us with a intense (1 μJ) and ultra-short (50 fs) VUV beam. The design of the experiment implantation is discussed, taken into account the performances of the generation process, the focusing of the selected harmonic into the modulator, and the resistance of the optical components. Besides one should consider the vacuum needs, the geometrical problems and the mechanics for the under UHV mirrors translation. One first chamber is dedicated to the harmonic generation. A second one is used for spectral selection and adaptation of the harmonic in the modulator. Finally theoretical estimates of the performances relying on 1D simulations using PERSEO code and 3D simulations using GENESIS code are also given.

• L. Giannessi, M.C. Carpanese, F. Ciocci, G. Dattoli, A. Dipace, A. Doria, G.P. Gallerano, E. Giovenale, G. Parisi, M. Quattromini, A. Renieri, C. Ronsivalle, E. Sabia, S. Spampinati, I.P. Spassovsky
  ENEA C.R. Frascati, Frascati (Roma)
• D. Alesini, M.E. Biagini, A. Drago, M. Ferrario, V. Fusco, A. Ghigo, B. Spataro, C. Vaccarezza, C. Vicario
  INFN/LNF, Frascati (Roma)
• M. Bougeard, B. Carre, M.-E. Couprie, D. Garzella, M. LABAT, G. Lambert, H. Merdji, P. Salieres
  CEA/Saclay, Gif-sur-Yvette
• M. Mattioli, P. Musumeci, M. Petrarca
  Universita di Roma I La Sapienza, Roma
• M.  Migliorati, L. Palumbo
  Rome University La Sapienza, Roma
• M. Nisoli, S. Stagira, S. de Silvestri
  Politecnico/Milano, Milano
• L. P. Poletto, G. T. Tondello
  Univ. degli Studi di Padova, Padova

Funding: Work supported by the EU Commission in the sixth framework programme, contract no. 011935 – EUROFEL.

Sources based on high order harmonics generated in gas with high power Ti:Sa lasers pulses represent promising candidates as seed for FEL amplifiers for several reasons, as spatial and temporal coherence, wavelength tunability and spectral range, which extends down to the 10(-9)m wavelength scale. This communication is devoted to the description of a research work plan that will be implemented at the SPARC FEL facility in the framework of the EUROFEL programme. The main goal of the collaboration is to study and test the amplification and the FEL harmonic generation process of an input seed signal obtained as higher order harmonics generated both in crystal (400nm and 266 nm) and in gas (266nm, 160nm, 114nm) from a high intensity Ti:Sa laser pulse.