Giannessi, L.
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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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| MOPP015 | Beam Dynamics Studies for the SPARXINO Linac | 67 |
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The first phase of the SPARX project is essentially an R&D activity focused on developing techniques and critical components for future X-ray FEL facilities. The SPARXINO test facility will generate ultra-high peak brightness electron beams at 1 GeV, thanks to the upgrade of the existing Frascati 800 MeV linac. This facility will allow driving a single pass FEL experiment in the range of 3-5 nm, both in SASE and SEEDED FEL configurations. A peculiarity of this linac design is the choice of integrating a rectilinear RF compressor in the early stage of the acceleration, producing a 300-500 A beam, with a magnetic chicane afterwards, for a further compression up to 1 kA. In this paper we discuss the dynamics of the beam, which is in the space charge dominated regime throughout almost all the linac. Start to end simulations and preliminary stability studies taking into account some significant parameter fluctuations are also reported. |
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| MOPP056 | Phase Shifters for the SPARC Undulator System | 187 |
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In the framework of the SPARC FEL experiment, a 14-m long undulator divided into six sections is presently under construction (by ACCEL Instruments GmbH). In order to correct the phase difference between the electron beam and the radiation, a tunable device will be inserted at the end of each of the six sections of the undulator. In this paper a preliminary design of this device, performed with RADIA code, is proposed,. The phase shifter consists of two groups of a few permanent magnets, arranged as in the main undulator in a variable gap magnet assembly. Adjusting the gap allows to correct the electron-radiation phase difference. Results from beam dynamics simulation, performed with GENESIS code, show the impact of the phase shifter on the characteristics of the output laser field. |
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| MOOC001 | Non Linear Pulse Evolution in Seeded and Cascaded FELs | 210 |
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The advances in laser technology have made available very short and intense laser pulses which can be used to seed a high gain single pass Free-Electron Laser (FEL) amplifier. With these seed pulses, a regime of the FEL interaction where the radiation evolution is simultaneously dominated by non-linear effects (saturation) and time-dependent effects (slippage) can be explored. This regime is characterized by the propagation of a solitary wave-like pulse where the power of the optical wave grows quadratically with time, its pulse length decreases and the spectral bandwidth increases. We analyze the interplay between the field and particles dynamics of this propagation regime which was studied before and termed superradiance. Furthermore we analyze the properties of the strong higher order harmonics emission from this wave and its behaviour when propagating in a cascade FEL. The superradiant pulse is indeed capable of passing through the stages of a cascade FEL and to regenerate itself at the wavelength of the higher order harmonic. The optical pulse obtained is shorter than a cooperation length and is strongly chirped in frequency, thus allowing further longitudinal compression down to the attosecond time-scale. |
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| TUPP013 | Spectral Properties of Planar Bi-Harmonic Undulators and Their Use for FEL Operation | |
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We study the spectral details of planar bi-harmonic undulators and show that they have quite interesting properties. They can indeed be exploited to enhance or suppress harmonics and can be exploited in high gain segmented FEL devices to make more efficient the mechanisms of harmonic generation. We also show that the formalism we develop can be extended to the multi-component case and can usefully be exploited to study undulator magnetization errors. |
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| THPP032 | An Experimental Test of Superradiance in a Single Pass Seeded FEL | 526 |
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Funding: Work suppoted by the Brookhaven National Lab and Office of Naval Research The SDL facility at BNL[1] is an excellent platform to explore some of the recent ideas related to superradiance in a seeded single pass FEL. At the SDL facility there is an operating FEL with a Ti:Sapphire seed laser and a high brightness e-beam with an energy up to 250 MeV. Seeding may be realized with pulses shorter than the e-beam bunch length to induce the superradiant regime. A status report concerning this experiment will be presented. [1] A. Doyuran et al., PRSTAB, Vol. 7, 050701 (2004). |
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| THPP019 | Status of the SPARX FEL Project | 491 |
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The first phase of the SPARX project, now funded by MIUR (Research Department of Italian Government), is an R&D activity focused on developing techniques and critical components for future X-ray FEL facilities. This project is the natural extension of the activities under development within the ongoing SPARC collaboration. The aim is the generation of electron beams characterized by an ultra-high peak brightness with a linear accelerator based on the upgrade of the existing Frascati 800 MeV LINAC and to drive a single pass FEL experiment in the range of 3-5 nm, both in SASE and SEEDED FEL configurations, exploiting the use of superconducting and exotic undulator sections. In this paper we discuss the present status of the collaboration. |
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