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| MOPPH001 |
Coherent Harmonic Generation on UVSOR-II Storage Ring
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37 |
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- M. Labat, G. Lambert
CEA, Gif-sur-Yvette
- M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- T. Hara
RIKEN Spring-8 Harima, Hyogo
- M. Hosaka, M. Katoh, A. Mochihashi, M. Shimada, J. Yamazaki
UVSOR, Okazaki
- D. Nutarelli
LAC, Orsay
- Y. Takashima
Nagoya University, Nagoya
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In the Coherent Harmonic Generation Free Electron Laser configuration, an external seed signal, a commercial laser source, is focused inside the first undulator. The interaction between the electron beam and this seed leads to a more coherent light emission. Such devices are very promising for short wavelength operation with a rather compact facility. Experiments have been performed on the UVSOR-II Storage Ring (Okazaki, Japan) with electrons stored at 600 MeV, and using a 2.5 mJ Ti:Sa laser at 800 nm wavelength, 1 kHz repetition rate, and 100 fs up to 2 ps pulse duration, allowing emission at 266 nm. This third harmonic has been characterised versus various parameters. Optimizations have been realized on the electron beam and laser synchronisation, seed characteristics (focussing point, energy, and pulse duration). The dependency of the harmonic signal on the gain (undulator gap, magnetic functions) has also been studied. Theory is compared to experiment using both analytical models and simulation. These encouraging results make UVSOR-II storage ring an active test facility for Coherent Harmonic Generation scheme, as well as a potential VUV source for users experiments.
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| MOPPH028 |
Future Seeding Experiments at SPARC
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95 |
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- L. Giannessi, S. Ambrogio, F. Ciocci, G. Dattoli, A. Doria, G. P. Gallerano, E. Giovenale, M. Quattromini, A. Renieri, C. Ronsivalle, I. P. Spassovsky
ENEA C. R. Frascati, Frascati (Roma)
- D. Alesini, M. E. Biagini, R. Boni, M. Castellano, A. Clozza, A. Drago, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, M. Migliorati, L. Palumbo, C. Sanelli, F. Sgamma, B. Spataro, S. Tomassini, C. Vaccarezza, C. Vicario
INFN/LNF, Frascati (Roma)
- M. Bougeard, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Salieres, O. Tcherbakoff
CEA, Gif-sur-Yvette
- M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- A. Dipace, E. Sabia
ENEA Portici, Portici (Napoli)
- M. Mattioli
Università di Roma I La Sapienza, Roma
- P. Musumeci, M. Petrarca
INFN-Roma, Roma
- M. Nisoli, G. Sansone, S. Stagira, S. de Silvestri
Politecnico/Milano, Milano
- P. L. Ottaviani, S. Pagnutti, M. Rosetti
ENEA-Bologna, Bologna
- L. P. Poletto, G. T. Tondello
Univ. degli Studi di Padova, Padova
- L. Serafini
INFN-Milano, Milano
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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 10-9m wavelength scale. This communication is devoted to the description of a research work plan that is under implementation 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.
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| MOPPH046 |
Seeding the FEL of the SCSS Prototype Accelerator with Harmonics of a Ti:Sa Laser Produced in Gas.
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138 |
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- G. Lambert, M. Bougeard, W. Boutu, B. Carré, D. Garzella, M. Labat
CEA, Gif-sur-Yvette
- O. V. Chubar, M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- T. Hara, H. Kitamura, T. Shintake
RIKEN Spring-8 Harima, Hyogo
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A particular seeded configuration will be tested in 2006 on the SCSS test facility (SPring-8 Compact Sase Source, Japan). This facility is based on a thermionic cathode electron gun (1 nC), a C-band LINAC (5712 MHz, 35 MV/m) and two in-vacuum undulators (15 mm of period). The maximum electron beam energy is 250 MeV and the SASE emission from visible to 60 nm can be obtained. The external source, obtained by the High order Harmonic Generation (HHG) process, can be tuned from the 3th (260 nm) to the 13th harmonic (60 nm) of a Ti: Sa laser generated in a gas cell. The experiment contains a first chamber, dedicated to harmonic generation and a second one for harmonic beam diagnostics and adaptation of the harmonic waist in the modulator. The tests have been performed in Saclay (15 mJ, 10 Hz, 50 fs). An energy of 2e-6J with a high stability for the 3th harmonic and a good transversal shape with an optimized energy level and a high stability for the 13th harmonic have been obtained at the modulator center place. The performances using PERSEO, GENESIS and SRW will be updated. The chambers will be installed on the SCSS test facility in the beginning of July for seeding tests during summer.
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| MOPPH047 |
Seeding SPARC Facility with Harmonic Generation in Gases: Preliminary Tests of the Harmonic Generation in Gas Chamber
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142 |
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- O. Tcherbakoff, M. Bougeard, P. Breger, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Monchicourt, P. Salieres
CEA, Gif-sur-Yvette
- M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- A. Doria, L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
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A coherent short wavelength source can be realised with a Free Electron Laser by using High Gain Harmonic Generation configuration. The injection of an external light source in the first part of an undulator results in a coherent light emission in its second part. The SPARC FEL (Frascati, Italy), delivering an electron beam at 200 MeV passing through an undulator of 6 sections, can be configured to test such schemes. We propose to use High order Harmonic Generation (HHG) in gases process as the seed. HHG produces a coherent XUV source by focusing an intense laser pulse into a gas medium. This beam, composed of odd harmonics of the fundamental laser, is then shaped using a telescope of two spherical mirrors, allowing the focusing at a given position, in the SPARC undulator. Appropriate tuning of the undulator gaps will amplify the 3rd and 5th harmonics seeded, and non-linear harmonics of those wavelengths, allowing the perspective of producing VUV coherent radiation. The chambers for harmonic generation and shaping have been realised and tested at the CEA (Saclay, France). We present these tests as well as simulations of the expected performances of the SPARC FEL with this seed.
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| MOPPH048 |
The ARC-EN-CIEL FEL Proposal
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146 |
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- C. Bruni, O. V. Chubar, J.-M. Filhol, A. Loulergue, L. Nahon
SOLEIL, Gif-sur-Yvette
- P. Bosland, B. Carré, M.-E. Couprie, G. Devanz, D. Garzella, O. Gobert, Ph. Hollander, M. Jablonka, M. Labat, G. Lambert, M. Luong, F. Meot, P. Monot, A. Mosnier, G. Petite, O. Tcherbakoff, B. Visentin
CEA, Gif-sur-Yvette
- J.-R. Marquès
LULI, Palaiseaux
- H. Monard, J.-M. Ortega
CLIO/ELYSE/LCP, Orsay
- A. Rousse
LOA, Palaiseau
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ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray in France. Phase 1 aims at exploiting the different sources of seeding, in particular Harmonic generation in Gas (HHG), to improve the longitudinal coherence and shortening the output radiation wavelength in a rather compact device. Phase 2 uses a CW 10 KHz 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches for HHG seeded High Gain harmonic Generation extending to 1 nm. In phase 3, fs undulator sources in the IR, VUV and X ray and a FEL oscillator in the 10 nm range will be implemented on ERL beam loops for beam current or energy enhancement. Electron plasma acceleration and fs hard X ray produced by Thomson Scattering are also foreseen. Preliminary studies are carried out in the frame of the EUROFEL collaboration, concerning the electro-optical measurement at ELYSE, carbon nanotubes, synchronisation and beam shaping for the gun, seeding with high harmonics produced in gas on SPARC and compensation of microphonics for the Linac.
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