| Paper |
Title |
Page |
| MOPPH003 |
The Effect of Shot-Noise on the Start-Up of the Fundamental and Harmonics in Free-Electron Lasers
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9 |
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- H. Freund, W. H. Miner
SAIC, McLean
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
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The problem of radiation start-up in FELs is important in the simulation of virtually all FEL configurations including oscillators and amplifiers in both seeded-MOPA (Master Oscillator Power Amplifier) and SASE (Self-Amplified Spontaneous Emission) modes. Both oscillators and SASE FELs start up from spontaneous emission due to shot-noise that arises from the random fluctuations in the electron phase distribution. The injected power in a MOPA is usually large enough to overwhelm the shot-noise; however, this noise must be treated correctly to model the initial start-up of the harmonics. We discuss and compare two different shot noise models that are implemented in both 1D wiggler-averaged (PERSEO) and non-wiggler-averaged (MEDUSA1D) simulations, and a 3D, non-wiggler-averaged (MEDUSA) formulation. These models are compared for examples describing both SASE and MOPA configurations in 1D in steady-state and time-dependent simulations, and remarkable agreement is found between PERSEO and MEDUSA1D. In addition, 3D correction factors have been included in the MEDUSA1D and PERSEO, and show reasonable agreement with MEDUSA for a sample MOPA in steady-state and time-dependent simulations.
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| 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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| MOPPH066 |
The ARC-EN-CIEL Fourth Generation Light Source Proposal
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131 |
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- M.-E. Couprie, C. Benabderrahmane, O. V. Chubar, J. Denard, P. Dumas, J.-M. Filhol, M. Idir, M. Labat, P. Lebasque, A. Lestrade, M. Louvet, P. Marchand, O. Marcouillé, P. Mercere, P. Morin, L. S. Nadolski, L. Nahon
SOLEIL, Gif-sur-Yvette
- C. Bruni
LAL, Orsay
- E. Collet
University of Rennes, Rennes
- D. Garzella
CEA, Gif-sur-Yvette
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
- G. Lambert, P. Zeitoun
LOA, Palaiseau
- J. Luning
CCPMR, Paris
- M. Meyer
LIXAM, Orsay
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The ARC-EN-CIEL project proposes a suit of novel light sources for the scientific community. Three FEL (LEL1, LEL2 and LEL4) sources rely on High Gain Harmonic Generation radiation and their Non Linear Harmonics seeded with the High Order Harmonics generated in gas. LEL1 will cover the 200-1.5 nm spectral range with 100-30 fs FWHM pulses, adjustable in polarisation, at a few kHz. LEL2 will provide 10-0.6 nm radiation with planar polarisation, with 100-30 fs pulses at a few kHz repetition rate. LEL4 will cover the 2-0.2 nm range, with 50-30 fs pulses at 1 kHz. LEL3 is a FEL oscillator in the 40-8 nm range with a repetition rate of 4.5 MHz. These FEL sources will reach MW to GW of peak power. In addition, undulator radiation will provide 200 fs pulses with energies up to 20 keV. FEL calculations are presented. . The accelerator is based on superconducting technology to enable a high repetition rate. ARC-EN-CIEL is well adapted for studies in various scientific domains using coherent imaging, linear spectroscopy, pump-probe experiments, non-linear and high intensities studies. The use of plasma acceleration in the project is under investigation.
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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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| TUPPH012 |
Single spike experiments with the SPARC SASE FEL
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258 |
| |
- M. Ferrario, M. Boscolo, L. Palumbo, C. Vaccarezza
INFN/LNF, Frascati (Roma)
- G. Andonian, E. Hemsing, G. Marcus, S. Reiche, J. B. Rosenzweig
UCLA, Los Angeles, California
- A. Bacci, I. Boscolo, F. Castelli, S. Cialdi, V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano
- L. Giannessi, C. Ronsivalle
ENEA C. R. Frascati, Frascati (Roma)
- M. Serluca
INFN-Roma, Roma
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We describe in this paper a possible experiment with the existing SPARC photoinjector to test the generation of sub-picosecond high brightness electron bunches able to produce single spike radiation pulses at 500 nm with the SPARC self-amplified spontaneous emission free-electron laser (SASE-FEL). The main purpose of the experiment will be the production of short electron bunches as long as few SASE cooperation lengths and to validate scaling laws to foresee operation at shorter wavelength in the future operation with SPARX. We present in this paper start to end simulations of the expected FEL performance and discuss the layout of the machine, including the diagnostics to measure the FEL pulse length and other aspects of FEL performance. The experience gained from this experiment, will help in the configuration of the VUV and X-ray FEL SPARX to obtain FEL pulses below 10 fs.
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| TUPPH018 |
Longitudinal Diagnostic for Single-Spike SASE FEL Operation
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274 |
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- G. Marcus, G. Andonian, A. Fukasawa, S. Reiche, J. B. Rosenzweig
UCLA, Los Angeles, California
- M. Ferrario, L. Palumbo
INFN/LNF, Frascati (Roma)
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
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The possibility of ultra-short beam, very low charge, short wavelength FELs at SPARC has been recently investigated. This paper explores the development of a longitudinal diagnostic that will provide the capability to characterize the short wavelength radiation based on the Frequency Resolved Optical Gating (FROG) technique. The paper includes studies of pulses simulated for the SPARC case using GENESIS and reconstructed using the FROG algorithm as well as proposed experimental layouts for the device.
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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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