Lambert, G.
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| MOPP012 | Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti:Sa Laser Produced in Xe Gas | |
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In order to reach very short wavelengths in systems based on Free Electrons Laser (FEL), and to have a more compact, fully coherent and tunable source, a particular seeding configuration is studied here. It is foreseen to test it as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). SCSS phase 1 is a linac-based FEL project, providing a compact SASE source with high brightness in the X-ray range. The external laser source, which is employed, is straightfully in the XUV range, the 13th harmonic of a Ti:Sa femtosecond laser (61.5 nm), generated in Xe gas. This harmonic can be now easily generated by focusing the Ti: Sa laser (25 mJ, 10 Hz, 100 fs) on a 10 Hz pulsed Xe gas cell. This High order Harmonics Generation (HHG) process provides us with a VUV beam with intense (1 μJ) and ultra-short (50 fs) properties. |
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| MOOC004 | Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti: Sa Laser (61.5 nm) Produced in Xe Gas | 224 |
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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. |
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| MOPP011 | The ARC-EN-CIEL FEL Proposal | 55 |
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ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light), the French project of a fourth generation light source aims at providing the user community with coherent femtosecond light pulses covering from UV to soft X ray. It is based on a CW 1 GeV superconducting linear accelerator delivering high charge, subpicosecond, low emittance electron bunches with a high repetition rate. The FEL is based on in the injection of High Harmonics in Gases in a High Gain Harmonic Generation scheme, leading to a rather compact solution. The produced radiation extending down to 0.8 nm with the Non Linear Harmonic reproduces the good longitudinal and transverse coherence of the harmonics in gas. Optional beam loops are foreseen to increase the beam current or the energy. They will accommodate fs synchrotron radiation sources in the IR, VUV and X ray ranges and a FEL oscillator in the 10 nm range. An important synergy is expected between accelerator and laser communities. Indeed, electron plasma acceleration will be tested for possible future compact electron beam sources for Xray FEL. Fs hard X ray can also be produced by Thomson Scattering. An overview of the user scientific case will also be given. |
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| MOPP014 | Status of the Seeding Experiment at SPARC | 63 |
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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. |
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| THPP004 | Remaining Dynamics in SR-FELs Stabilized by Feedback Control: Modeling of the Field Evolution and Experiments at UVSOR | |
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FEL oscillator operation is known to be strongly affected by instability issues. Recently, it has been demonstrated experimentally and theoretically that the "macropulse instabilities" which affects the laser pulse train enveloppe can be suppressed using feedback control techniques. From a detailed experimental and numerical study, we show here that "hidden" dynamical evolutions remain in controlled FELs. Though not visible in the evolution of the pulse enveloppe, this affects the internal pulse shape evolution, and thus the FEL spectrum and coherence properties. The experiments are performed on the UVSOR FEL. The modeling is made using the field master equation [1] based on the Dattoli/Elleaume approach. The shochastic nature of spontaneous emission is taken into account, and appears as an essential ingredient. [1] S. Bielawski, C. Bruni, D. Garzella, G.-L. Orlandi and M.E. Couprie, Phys. Rev. Lett. to appear. |
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