| Paper |
Title |
Page |
| 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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| THPC065 |
Orbit Stability Status and Improvement at SOLEIL
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3134 |
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- L. S. Nadolski, J. C. Besson, F. Bouvet, P. Brunelle, L. Cassinari, J.-C. Denard, J.-M. Filhol, N. Hubert, J.-F. Lamarre, A. Loulergue, A. Nadji, D. Pedeau, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette
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SOLEIL is a 2.75 GeV third generation synchrotron light source delivering photons to beam-lines since January 2007. Stability of the beam-line source points is crucial for the user experiments. Typically this stability has to be below one tenth of the transverse beam sizes. This is challenging especially in the vertical plane leading to sub-micrometer values. This paper will describe the position stability achieved today without and with the slow orbit feedback. Impact of different noise sources and present limitations will be described. To end an improvement strategy will be given for short and medium terms.
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| THPC115 |
Commissioning of SOLEIL Fast Orbit Feedback system
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3248 |
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- N. Hubert, L. Cassinari, J.-C. Denard, J.-M. Filhol, N. Leclercq, A. Nadji, L. S. Nadolski, D. Pedeau
SOLEIL, Gif-sur-Yvette
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The Fast Orbit Feedback system at SOLEIL is fully integrated into the BPM system equipped with Libera modules. Indeed, the correction algorithm has been embedded into the Libera FPGA which directly drives the power supplies of dedicated air coil correctors. The beam position measurements of the 120 BPMs are distributed around the storage ring by a dedicated network. Then, the correction is computed and applied at a rate of 10 kHz to 48 correctors installed over stainless-steel bellows, on each side of every straight section. The BPM system has been operational for some time. The fast orbit feedback system is in its commissioning phase. The design and first results of the latter are reported.
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| THPP142 |
Vacuum Conditioning of the SOLEIL Storage Ring with Extensive Use of NEG Coating
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3696 |
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- C. Herbeaux, N. Béchu, J.-M. Filhol
SOLEIL, Gif-sur-Yvette
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The vacuum system of the SOLEIL storage ring is designed using a combination of standard pumps like Sputter Ion Pumps and Titanium Sublimation Pumps (TSP) and Non Evaporable Getter (NEG) coating. Following the ESRF results on low gap insertion device (ID) chambers, it was decided to use, in addition to the traditional pumps, NEG coating deposited by magnetron sputtering on extruded aluminium vessels. This has been applied in an extensive way to all the straight vessels of the storage ring that means quadrupole vessels and ID vessels, which represent about 56% of the circumference. The starting configuration of the SOLEIL vacuum system included all the NEG coated low gap ID chambers among which a 10.5 m long chamber. Conditioning of the vacuum system over an integrated beam dose of 500 A.h will be presented. The periodical re-activations of the TSP performed early 2007 improved significantly the conditioning rate. A comparison of the vacuum behaviour of two similar cells one with NEG coating and traditional pumping versus one with only NEG coating demonstrates the ability of the NEG coating to keep alone the pressure at low level.
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