| Paper |
Title |
Page |
| MOPC005 |
The ARC-EN-CIEL Radiation Sources
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73 |
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- M.-E. Couprie, M. Labat
CEA, Gif-sur-Yvette
- C. Benabderrahmane, O. V. Chubar, G. Lambert, A. Loulergue, O. Marcouillé
SOLEIL, Gif-sur-Yvette
- C. Bruni
LAL, Orsay
- L. Giannessi
ENEA C. R. Frascati, Frascati (Roma)
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The ARC-EN-CIEL project proposes a panoply of light sources for the scientific community on a 1 GeV superconducting LINAC (phase 2) on which two ERL loops (1 and 2 GeV) are added in phase 3. LEL1 (200-1.5 nm), LEL2 (10-0.5 nm) and LEL4 (2-0.2 nm) are three kHz High Gain Harmonic Generation Free Electron Laser sources seeded with the High order Harmonics generated in Gas, with 100-30 FWHM pulses. A collaboration, which has been set-up with the SCSS Prototype Accelerator in Japan for test this key concept of ARC-EN-CIEL, has led to the experimental demonstration of the seeding with HHG and the observation up the 7th non linear harmonic with a seed at 160 nm. Besides. LEL3 (40-8 nm) installed on the 1 GeV loop is a MHz FEL oscillator providing higher average power and brilliance. In addition, in vacuum undulator spontaneous emission source extend the spectral range above 10 keV and intense THz radiation is generated by edge radiation of bending magnets. Optimisations and light sources characteristics are described.
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| MOPC017 |
Operation of the UVSOR-II CHG-FEL in Helical Configuration
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106 |
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- M. Labat
CEA, Gif-sur-Yvette
- M.-E. Couprie, G. Khalili
SOLEIL, Gif-sur-Yvette
- M. Hosaka, N. Yamamoto
Nagoya University, Nagoya
- M. Katoh, M. Shimada
UVSOR, Okazaki
- A. Mochihashi
JASRI/SPring-8, Hyogo-ken
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In the Coherent Harmonic Generation Free Electron Laser (CHG-FEL) configuration, an external laser source injected inside a first undulator modulates in energy, and consequently in phase, an electron bunch, allowing coherent radiation in a second undulator. The CHG-FEL implemented on UVSOR-II storage ring (Okazaki, Japan) consists of a 600 MeV electron beam, and of a 2.5 mJ Ti:Sa seeding laser at 800 nm wavelength, 1 kHz repetition rate, and 100 fs up to 2 ps pulse duration. Operation in planar configuration of the undulators is being characterized since 2005. Recent experiments enabled a step forward using helical configuration of the undulators. A description of the experimental setup is given, and the main results are presented: influence of seeding laser parameters (polarisation, average power, focusing) on the intensity and beam profile of the second and third coherent harmonics. Those investigations provide attractive insights for the future HGHG FEL sources, about to deliver sub-nm and sub-ps pulses.
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| MOPC018 |
Seeding the FEL of the SCSS Test Accelerator with the 5th Harmonic of a Ti: Sa Laser Produced in Gases
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109 |
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- G. Lambert, O. V. Chubar, M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- M. Bougeard, B. Carré, D. Garzella, O. B. Gobert, M. Labat, H. Merdji, P. Salieres
CEA, Gif-sur-Yvette
- T. Hara, T. Ishikawa, H. Kitamura, T. Shintake, M. Yabashi
RIKEN/SPring-8, Hyogo
- K. Tahara, Y. T. Tanaka, T. Tanikawa
RIKEN Spring-8 Harima, Hyogo
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We present the strong amplification of the 5th harmonic of a Ti: Sa laser (10 Hz, 100 fs) generated in a Xe gas cell, i.e. 160 nm, and the generation of intense and coherent odd and even Non Linear Harmonics (NLH) from 80 nm to 23 nm. The experiment has been carried out on the SCSS (SPring-8 Compact SASE Source, Japan) Test Accelerator FEL. This facility is mainly based on a thermionic cathode electron gun, a C-band LINAC (5712 MHz, 35 MV/m) and an in-vacuum undulator (15 mm of period, 2 sections of 4.5 m length). The external source is properly focused in the first undulator section in order to efficiently interact with the electron beam (150 MeV, 10 Hz, 0.5-3 ps). In case of high peak current mode, the 160 nm seed light is amplified by a factor of 7000 in the first undulator section. Moreover, the amplification can be observed even for very low HHG seed level. This result opens new perspectives for seeding at short wavelengths in the XUV to soft X-Ray region. Association with NLH, HGHG (High Gain Harmonic Generation) and/or cascade schemes would allow the generation of fully coherent X-ray radiations from the “water window” spectral range to the Angstrom region.
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| MOPC023 |
ARC-EN-CIEL Beam Dynamics
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115 |
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- A. Loulergue, M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- C. Bruni
LAL, Orsay
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ARC-EN-CIEL project is based on a CW 1.3 GHz superconducting linac accelerator delivering high charge, subpicosecond and low emittance electron bunches at high repetition rate. According to the electron energy, it provides tunable light source of high brightness in the VUV to soft X-ray wavelength domain. The project will evolve into three phases: first and second phases are based on high brightness single pass SC linac configuration with a low average current (few μA), while third phase comports recirculation loops to increase the average current (up to 100 mA). This paper deals with electron beam dynamics issues for the single pass configuration in the two first phases from the RF gun to undulators including magnetic compression stages. In the ERL configuration of the third phase, the accelerator scheme and focusing are investigated in order to take into account collective effects as Beam Break Up instability.
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| WEPC016 |
Operation Status and Performances Upgrade on SOLEIL Storage Ring
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2022 |
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- J.-M. Filhol, J. C. Besson, F. Bouvet, P. Brunelle, L. Cassinari, M.-E. Couprie, J.-C. Denard, C. Herbeaux, J.-F. Lamarre, J.-P. Lavieville, P. Lebasque, M.-P. Level, A. Loulergue, P. Marchand, A. Nadji, L. S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette
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SOLEIL is the French 2.75 GeV third generation synchrotron light source delivering beam to users since January 2007. Beginning of 2008 up to 13 beam-lines are taking beam, 7 from insertion devices (IDs), 2 from IR ports, and 4 from dipole ports, and 6 of them are open to external Users. Users have a full control of their IDs. With a 300 mA stored beam current in multi-bunch filling pattern, and position stability in the few micron range, the main target performances have been reached. A beam of 50 mA in 8 bunches was delivered to users for the first time in December 2007 for time structure experiments. Operation and performance status will first be given, namely subsystem behaviour (RF, vacuum, …), beam optics, orbit stability, beam lifetime, and operation statistics. Then the main objectives for 2008 will be reviewed: delivery of 4000 hours of user beam time, installation and commissioning of a second cryomodule for reaching the 500 mA current target, construction and installation of 6 new IDs leading to a total number of 17, improvement of the orbit stability with a fast orbit feedback complementary to the slow orbit one, and preparation for top-up operation.
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| WEPC098 |
Development of Cryogenic Undulator CPMU at SOLEIL
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2225 |
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- C. Benabderrahmane, P. Berteaud, N. Béchu, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, C. A. Kitegi, J. L. Marlats, A. Mary, K. Tavakoli
SOLEIL, Gif-sur-Yvette
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On SOLEIL at 2.75 GeV, producing hard X rays requires short period and small gap in-vacuum hybrid permanent magnet undulators. Besides, higher achieved peak magnetic field can be while operating at cryogenic temperature Tc (around 140 K). When cooling down the permanent magnets, the remanence Br increases down to a certain temperature at which the process is limited by the appearance of the Spin Reorientation Transition phenomenon. The coercivity is also increased at Tc which improves significantly the resistance to radiation. R&D studies, aims at replacing SmCo by NdFeB permanent magnets whose Br of 1.4 T, could enable to increase at least by 30% the peak magnetic field at Tc. Unfortunately such magnet grade can’t be heated to high temperature without degrading the magnetic properties, which limits the residual pressure that can be achieved. Temperature gradient and mechanical deformation are also technical issues. Different permanent magnet grades at Tc are characterized. Studies are also carried out on a small assembly of four periods. Residual pressures obtained with or without partial baking on standard U20 in-vacuum undulators are compared.
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| WEPC102 |
Commissioning of the Electromagnetic Insertion Devices at SOLEIL
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2237 |
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- F. Briquez, P. Brunelle, O. V. Chubar, M.-E. Couprie, J.-M. Filhol, O. Marcouillé, F. Marteau, A. Nadji, L. S. Nadolski, M. Valleau, J. Vétéran
SOLEIL, Gif-sur-Yvette
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SOLEIL is the French 2.75 GeV third generation synchrotron radiation light source. Eleven undulators are installed yet in the storage ring and nineteen more Insertion Devices (ID) will be installed on the ring by January 2010. Among the installed IDs, there are four electromagnetic undulators of two different designs: one 640 mm period air coils undulator called HU640 and three 256 mm period undulators called HU256, made up of independent H yoke dipoles. The HU640 provides photons in any polarisation from linear to elliptical, in a range extending from 5 to 40 eV, thanks to three different groups of coils powered independently. The HU256, which are subject to hysteresis, provide horizontal and vertical, periodic or quasi-periodic linear polarisations, and also circular polarisation, covering a total range from 10 eV to 1 keV. The effects of each undulator on the closed orbit have been extensive studied, and compensated, using dedicated embedded steering coils. The correction method will be explained and its results will be shown and compared to the magnetic measurements. Finally, the first measurements of the radiation produced will be shown and compared to previsions.
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| WEPC106 |
Compensation of Variable Skew- and Normal quadrupole Focusing Effects of APPLE-II Undulators with Computer-aided Shimming
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2246 |
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- O. V. Chubar, F. Briquez, M.-E. Couprie, J.-M. Filhol, E. Leroy, F. Marteau, F. Paulin, O. Rudenko
SOLEIL, Gif-sur-Yvette
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Variable (phase- and gap-dependent) skew- and normal-quadrupole focusing effects of APPLE II undulators on electron beam are reportedly complicating practical use of this type of insertion devices in many synchrotron radiation sources. We show that these undesirable effects, whatever their "origin", can be well controlled and in many cases efficiently compensated during the standard "virtual" shimming of APPLE-II undulators. Our method exploits small variations of the skew- and normal-quadrupole focusing components resulting from extra magnetic interaction, introduced by displacements of permanent magnet blocks during the shimming procedure, at different undulator phase and gap values. These variations can be calculated to a high accuracy, included into the corresponding "shim signatures" of magnetic field integrals, and used, along with undulator magnetic measurements data, for calculation of the most efficient magnet displacements. This approach is well suited for a computer-aided (e.g., genetic optimization based) shimming procedure. Practical results obtained with several APPLE-II undulators, which are currently successfully operating on the SOLEIL storage ring, are presented.
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| WEPC107 |
Observation and Interpretation of Dynamic Focusing Effects Introduced by APPLE-II Undulators on Electron Beam at SOLEIL
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2249 |
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- O. V. Chubar, P. Brunelle, M.-E. Couprie, J.-M. Filhol, A. Nadji, L. S. Nadolski
SOLEIL, Gif-sur-Yvette
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The paper presents the results of electron beam closed orbit distortion (COD) and tune shift measurements performed on three different APPLE-II type undulators when making horizontal displacements of the electron beam orbit in those straight sections of the SOLEIL storage ring where these undulators are installed. In agreement with data from other storage rings, our results show that, when APPLE-II undulators are used in elliptical, linear-vertical or linear-tilted polarization modes, the measured tune shifts and the COD can not be explained only by residual first-order focusing effects: taking into account the second-order, or dynamic focusing effects, is necessary. We describe a COD interpretation method allowing for straightforward comparison of the measured effects on electron beam with the corresponding predictions from calculations and magnetic measurements. The observed dynamic effects are in good agreement with calculations performed using RADIA code. We also discuss possible modification of the figures of merit to be used at computer-aided shimming of APPLE-II undulators, which would allow for simultaneous minimization of the first- and second-order focusing effects.
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| WEPC120 |
An In Vacuum Wiggler WSV50 for Producing Hard X-rays at SOLEIL
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2288 |
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- O. Marcouillé, P. Brunelle, O. V. Chubar, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, J. L. Marlats, A. Mary, K. Tavakoli
SOLEIL, Gif-sur-Yvette
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SOLEIL is a medium energy storage ring (2.75 GeV) operating since 2006. The production of intense high energy photon beams requires insertion devices with high magnetic field and large number of periods. To cover the 20 keV-50 keV Photon Energy range, an in vacuum wiggler has been preferred to a superconducting wiggler. This choice results from a compromise between photon flux, investment and running cost. Deep studies have been performed to find the optimum magnetic field and period producing the maximum flux in the dedicated spectral range (20-50 keV). The wiggler is composed of 38 periods of 50 mm producing a 2.1 T magnetic field at a minimum gap of 5.5 mm. To minimize the high magnetic forces acting between the magnet arrays (10 tons), two compensation systems, composed of either springs or magnet blocks, have been designed. This paper presents the spectral performances of the wiggler compared with an optimized superconducting wiggler, the mechanical and magnetic design of the wiggler and the first tests of the compensation system.
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| WEPC075 |
Recent Results and Future Perspectives of the SPARC Project
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2169 |
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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, B. Marchetti, A. Marinelli, C. Marrelli, 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
INFN-Milano, 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, 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
- M. Mattioli, M. Serluca
INFN-Roma, Roma
- M. Migliorati, A. Mostacci
Rome University La Sapienza, Roma
- M. Petrarca
Università di Roma I La Sapienza, Roma
- J. B. Rosenzweig
UCLA, Los Angeles, California
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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, a Thomson backscattering source and a plasma accelerator experiment. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. As a first stage of the commissioning a complete characterization of the photoinjector has been accomplished with a detailed study of the emittance compensation process downstream the gun-solenoid system and the demonstration of the emittance oscillation in the drift. 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 and the demonstration of the “velocity bunching” technique in the linac. In this paper we report the experimental results obtained so far and the scientific program for the near future.
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