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Title |
Page |
| MOPPH009 |
Comparison of HGHG and Self Seeded Scheme for the Production of Narrow Bandwidth FEL Radiation
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25 |
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- A. Marinelli
Rome University La Sapienza, Roma
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
- C. Pellegrini, S. Reiche
UCLA, Los Angeles, California
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One goal of several FEL facilities operating in the soft x-ray spectral range, is the production of narrow bandwidth FEL radiation. Several schemes have been proposed to obtain narrower bandwidths than that achievable with SASE-FELs. In this paper we investigate numerically, and compare, the properties of two schemes: Self-Seeding and High Gain Harmonic Generation. These schemes have been thoroughly studied analitically and numerically in the past. The aim of this work is to compare the performances of these schemes with respect to several non-ideal properties of the electron beam and seed laser, such as shot to shot energy fluctuations, nonlinear energy chirp and phase noise in the seed source. The work has been carried out with the aid of the time dependent FEL codes GENESIS (3D) and PERSEO (1D).
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| TUBAU04 |
Generation of Sub-fsec, High Brightness Electron Beams for Single Spike SASE FEL Operation
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214 |
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- J. B. Rosenzweig, M. P. Dunning, L. Faillace, A. Fukasawa, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci, B. D. O'Shea, C. Pellegrini, S. Reiche
UCLA, Los Angeles, California
- M. Boscolo, M. Ferrario, L. Palumbo, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma)
- L. Giannessi, C. Ronsivalle
ENEA C. R. Frascati, Frascati (Roma)
- V. Petrillo
Istituto Nazionale di Fisica Nucleare, Milano
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We present here the theory and computational modeling of beams in a new regime, where <1 pC beams are strongly velocity bunched at low energy, and then compressed at several GeV to less than a fsec. This regime of operation produces beams with thermally dominated transverse emittance, and mitigates many problems associated with the nC-level operation. These problems include CSR induced instability and intra-undulator wakes. The resulting beams have extremely high brightness, enabling very high gain, efficiency, and single spike operation. We present the scaling laws governing this regime, and the detailed example of the proposed SPARX FEL design.
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| TUPPH023 |
Quasicrystalline Beam Formation in RF Photoinjectors
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285 |
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- J. B. Rosenzweig, M. P. Dunning, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci
UCLA, Los Angeles, California
- M. Ferrario
INFN/LNF, Frascati (Roma)
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The recent observation of coherent optical transition radiation from the beam after the injector line at the LCLS has raised serious questions concerning the present model of beam dynamics in RF photoinjectors. We present here an analysis of what we term quasicrystalline beam formation. In this scenario, the relatively low longitudinal temperature, in combination with strong acceleration and, finally, temporal rearrangement due to bending, allows the longitudinal beam dimension to become more regular, on the microscopic scale of optical wavelengths, than expected from equilibrium statistical properties. This beam distribution then may then display a strong degree of coherence in its optical transition radiation output. We discuss further experimental investigations of this phenomenon.
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| TUPPH048 |
Recent Results of the SPARC Project
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359 |
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- M. Ferrario, D. Alesini, M. Bellaveglia, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, A. Marcelli, B. Marchetti, M. Migliorati, A. Mostacci, E. Pace, L. Palumbo, L. Pellegrino, R. Ricci, U. Rotundo, C. Sanelli, F. Sgamma, B. Spataro, F. Tazzioli, S. Tomassini, C. Vaccarezza, M. Vescovi, C. Vicario
INFN/LNF, Frascati (Roma)
- A. Bacci, I. Boscolo, F. Broggi, F. Castelli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, A. R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano
- M. Bougeard, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Salieres, O. Tchebakoff
CEA, Gif-sur-Yvette
- L. Catani
INFN-Roma II, Roma
- A. Cianchi
Università di Roma II Tor Vergata, Roma
- F. Ciocci, G. Dattoli, M. Del Franco, A. Dipace, A. Doria, G. P. Gallerano, L. Giannessi, E. Giovenale, G. L. Orlandi, S. Pagnutti, A. Petralia, M. Quattromini, C. Ronsivalle, E. Sabia, I. P. Spassovsky, V. Surrenti
ENEA C. R. Frascati, Frascati (Roma)
- M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- A. Marinelli, J. B. Rosenzweig
UCLA, Los Angeles, California
- M. Mattioli, M. Petrarca, M. Serluca
INFN-Roma, Roma
- J. Rossbach
Uni HH, Hamburg
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The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the “invariant envelope” matching , the demonstration of the “velocity bunching” technique in the linac and the characterisation of the spontaneous emission radiation in the SPARC undulators. In this paper we report the experimental results obtained so far.
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