Travish, G.
(Gil Travish)

MOPOS27 Status Report on SPARC Project
Alberto Renieri, Mariano Carpanese, Franco Ciocci, Giuseppe Dattoli, Antonio Di Pace, Andrea Doria, Francesco Flora, Gian Piero Gallerano, Luca Giannessi, Emilio Giovenale, Giovanni Messina, Luca Mezi, Pier Luigi Ottaviani, Simonetta Pagnutti, Giovanni Parisi, Luigi Picardi, Marcello Quattromini, Giuseppe Ronci, Concetta Ronsivalle, Elio Sabia, Mauro Sassi, Alberto Zucchini (ENEA C.R. Frascati, Frascati - Roma), Carlo Joseph Bocchetta, Miltcho B. Danailov, Gerardo D'Auria, Mario Ferianis (Elettra, Basovizza, Trieste), F. Alessandria, A. Bacci, Ilario Boscolo, F. Broggi, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, M. Romè, Luca Serafini (INFN Milano, Milano), D. Levi, Mario Mattioli, G. Medici, Pietro Musumeci (INFN Roma, Roma), L. Catani, E. Chiadroni, Sergio Tazzari (INFN-Roma2, Roma), David Alesini, M. Bellaveglia, Sergio Bertolucci, M.E. Biagini, Caterina Biscari, R. Boni, Manuela Boscolo, Michele Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, Massimo Ferrario, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, Susanna Guiducci, M. Incurvati, C. Ligi, F. Marcellini, Mauro Migliorati, C. Milardi, Luigi Palumbo, L. Pellegrino, Miro Preger, P. Raimondi, R. Ricci, C. Sanelli, Mario Serio, F. Sgamma, Bruno Spataro, A. Stecchi, A. Stella, Franco Tazzioli, Cristina Vaccarezza, Mario Vescovi, C. Vicario, M. Zobov (INFN/LNF, Frascati (Roma)), A. Cianchi, A. D'Angelo, R. Di Salvo, A. Fantini, D. Moricciani, Carlo Schaerf (Rome University Tor Vergata, Roma), D. H. Dowell, Paul J Emma, C. Limborg-Deprey, D. T. Palmer (SLAC, Menlo Park, California), James B Rosenzweig, Gil Travish (UCLA, Los Angeles, California), Sven Reiche (UCLA/DPA, Los Angeles - California)

We review the status of FEL source activity of the on going SPARC FEL experiment, developed within the framework of a collaboration among ENEA, CNR, INFN, INFM, Sincrotrone Trieste and University of Rome Tor Vergata. The project is aimed at realising a SASE FEL source, operating in the visible (around 500 nm), with an extended range of tunability down to the VUV (100nm) by the use of the mechanism of non-linear harmonic generation. The development of the relevant activities foresees the realisation of an advanced 150 MeV photo-injector source, aimed at producing a high brightness electron beams, needed to drive a SASE-FEL experiment and a 12 m long undulator. We present the status of the design and construction of the injector, of the undulator and of the e-beam transport line. In particular we discuss the choice of the project parameters, their optimisation and the sensitivity of the SPARC performance to any parameter variation. We will show, using start to-end simulations, what is the impact of the e-beam and of the undulator parameters on the characteristics of the output laser field and in particular on the amount of the non linearly generated power at higher harmonics.

THPOS56 VISA IB: Ultra-High Bandwidth, High Gain SASE FEL
Gerard Andonian, Ronald Barkley Agustsson, Alex Murokh, Claudio Pellegrini, Sven Reiche, James B Rosenzweig, Gil Travish (UCLA, Los Angeles, California), Marcus Babzien, Ilan Ben-Zvi, Jung Yun Huang, Vladimir N. Litvinenko, Vitaly Yakimenko (BNL, Upton, Long Island, New York), Ilario Boscolo, S. Cialdi, Alessandro Flacco (INFN Milano, Milano), Massimo Ferrario, Luigi Palumbo, C. Vicario (INFN/LNF, Frascati (Roma))

The results of a high energy-spread SASE FEL experiment, the intermediary experiment linking the VISA I and VISA II projects, are presented. A highly chirped beam (~1.7%) was transported without correction of longitudinal aberrations in the ATF dogleg, and injected into the VISA undulator. The output FEL radiation displayed an uncharacteristicly large bandwidth (~11%) with extremely stable lasing and measured energy of about 2 microJoules. Start-to-end simulations reproduce key features of the measured results and provide an insight into the mechanisms giving rise to such a high bandwidth. These analyses are described as they relate to important considerations for the VISA II experiment.

THPOS57 Acceleration of Electrons in a Diffraction Dominated IFEL
Pietro Musumeci, Chan Joshi, Claudio Pellegrini, J. Ralph, James B Rosenzweig, C. Sung, Sergei Tochitsky, Gil Travish (UCLA, Los Angeles, California), Sergey Tolmachev, Alexander Varfolomeev, Alexander Varfolomeev Jr., Timofey Yarovoi (RRC Kurchatov Institute, Moscow), Salime Boucher, Adnan Doyuran, Robert England, Rodney Yoder (UCLA/DPA, Los Angeles - California)

We report on the observation of energy gain in excess of 20 MeV at the Inverse Free Electron Laser Accelerator experiment at the Neptune Laboratory at UCLA. A 14.5 MeV electron beam is injected ina 50 cm long undulator strongly tapered both in period and field amplitude. A CO2 10 μ m laser with power >300 GW is used as the IFEL driver. The Rayleigh range of the laser (1.8cm) is shorter than the undulator length so that the interaction is diffraction dominated. Few per cent of the injected particles are trapped in stable accelerating buckets and electrons with energies up to 35 MeV are detected on the magnetic spectrometers. Experimental results on the scaling of the accelerator characteristics versus input parameters like injection energy, laser focus position and laser power are discussed. Three dimensional simulations are in good agreement with the electron energy spectrums observed in the experiment and indicate that substantial energy exchange between laser and electron beam only occurs in the first 25-30 cm of the undulator. An energy gradient of >70 MeV is inferred. In the second section of the undulator higher harmonic IFEL interaction is observed.