Giannessi, L.

Paper	Title	Page
MOPPH026	Overview of Perseo, a System for Simulating FEL Dynamics in Mathcad	91
	L. Giannessi ENEA C. R. Frascati, Frascati (Roma)
	The computing performances of today's personal computers are sufficient for executing interactively one dimensional FEL simulations. Mathcad is a versatile tool for implementing math expressions, plotting data and analysing results with the main prerogative of the simplicity of the user-interface. This suggested to develope a set of functions devoted to the simulation of FEL dynamics that can be accessed from the Mathcad environment. The result is Perseo, a flexible tool that can be simply programmed to set up FEL simulations in a wide variety of practical configurations. Perseo allows the time dependent simulation of SASE and seeded FEL configurations, oscillator configurations and exhotic configurations like master oscillator power amplifier or multiple stages cascaded FELs. The model include higher order harmonics and startup from shot-noise. Perseo is freely available at http://www.perseo.enea.it
MOPPH028	Future Seeding Experiments at SPARC	95
	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
	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.
MOPPH047	Seeding SPARC Facility with Harmonic Generation in Gases: Preliminary Tests of the Harmonic Generation in Gas Chamber	142
	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)
	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.
MOCAU05	Analysis of the Process of Amplification in a Single Pass FEL of High Order Harmonics Generated in a Gas Jet	248
	L. Giannessi, M. Quattromini ENEA C. R. Frascati, Frascati (Roma) P. Musumeci INFN-Roma, Roma M. Nisoli, G. Sansone, S. Stagira, S. de Silvestri Politecnico/Milano, Milano
	We have studied the amplification of high harmonics generated by a short infrared pulse in a gas jet, injected in a free electron laser amplifier. The high-order harmonic spectra have been simulated using a 3D non-adiabatic model that includes both the single atom response and the effect of the propagation of the XUV field inside the gas jet. The response of a single atom to the IR field is calculated in the framework of the Strong Field Approximation (SFA); The nonlinear polarization associated to this process is evaluated as the acceleration of the nonlinear dipole moment. This term is used as source term in the propagation of the harmonic field inside the gas jet. The propagation effect are extremely relevant for the temporal structure of the XUV field as the coherent interference of the dipole emission of the different atoms leads to the selection of only one XUV pulse for each semi-cycle of the driving IR field. The amplification in the free electron laser has been simulated both in 1D and 3D with Perseo and GENESIS 1.3 respectively. The effects of filtering the seed spectrum have been analyzed and the coherence properties of the light are considered.
	Slides
	Talk
THPPH031	Commissioning of the SPARC Photo-Injector	637
	M. Bellaveglia, D. Alesini, S. Bertolucci, M. E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, M. Migliorati, A. Mostacci, L. Palumbo, L. Pellegrino, M. A. Preger, R. Ricci, C. Sanelli, F. Sgamma, B. Spataro, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario INFN/LNF, Frascati (Roma) A. Bacci, I. Boscolo, F. Broggi, S. Cialdi, D. Giove, M. Mauri, A. R. Rossi, L. Serafini INFN-Milano, Milano L. Catani, E. Chiadroni, A. Cianchi, S. Tazzari INFN-Roma II, Roma L. Giannessi, M. Quattromini, A. Renieri, C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma) M. Mattioli, P. Musumeci, M. Petrarca INFN-Roma, Roma A. Perrone INFN-Lecce, Lecce J. B. Rosenzweig UCLA, Los Angeles, California
	The SPARC project is born to perform R&D activity headed to realize SASE-FEL experiments at 500nm and higher harmonic generation. The project foresees the realization of a high brightness photo-injector able to produce a 150-200MeV electron beam to drive FEL process inside a dedicated 14m long undulator. The machine is going to be assembled at LNF and its final configuration is made up of an RF gun, driven by a Ti:Sa laser, injecting into three SLAC type accelerating sections. Nowadays we are working in a photo-injector test phase, aiming to characterize the main hardware components and to investigate the behavior of the e-beam dynamics in the first meters of drift. To do this we utilize the emittance-meter, a home designed diagnostic device placed just after the RF gun, able to move 1.2 meters along the longitudinal axis to measure beam parameters. In this paper we report a more accurate description of the project, the status of the single systems constituting the machine and the most important results we obtained in the e-meter phase.