| Paper | Title | Page |
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| TUPE080 | Study of High Harmonic Generation at Synchrotron SOLEIL using an Echo Enabling Technique | 2308 |
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SOLEIL is presently installing a laser bunch slicing set-up to produce ultra-short X-ray pulses. We propose a method to generate coherent synchrotron radiation at high harmonics in a storage ring using an echo scheme. Like in the method proposed recently for free electron lasers, the echo scheme uses two modulators and two dispersive sections. We show that this can be done at the synchrotron SOLEIL by adapting the classical slicing scheme. In the present study at SOLEIL, the two laser/electrons interactions are planned to occur in two out of vacuum wigglers of period 150 mm, and the high harmonic radiation will be emitted in an APPLE-II type undulator with a period of 44mm or 80 mm in the beamline TEMPO or with a period of 52 mm in the beamline DEIMOS. |
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| WEPEA010 | Operation and Performance Upgrade of the SOLEIL Storage Ring | 2493 |
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The SOLEIL synchrotron light source is now delivering photons to 20 beamlines with a current of 400 mA in top-up mode. The long and short term H and V beam position stabilities are in the range of one micron thanks to the efficient slow and fast orbit feedbacks, and to the improved tunnel temperature regulation. The bunch by bunch transverse feedback is running with two independent H and V loops. To enable canted undulator implementations, a 3 magnet chicane has been installed in a medium straight whereas an additional triplet of quadrupole was inserted in the middle of a long straight to create a double low vertical beta. 17 insertion devices are now installed in the storage ring, 2 will be added early 2010, 8 are under construction, including a cryogenic undulator. Following the significant progression of the vacuum conditioning, the lifetime is now mainly Touchek limited. An electron bunch slicing set-up is also being installed to provide 100 fs long X-rays pulses to two existing beamlines. ~4500 hours will have been delivered in 2009 to the Beamlines with an availability above 96 % thanks to the very reliable operation of the unique SOLEIL RF system. |
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| WEPEA011 | Double Low Beta Straight Section for Dual Canted Undulators at SOLEIL | 2496 |
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SOLEIL is the French 2.75 GeV high brilliance third generation synchrotron light source delivering photons to 20 beamlines with a current of 400 mA in multibunch or hybrid modes, and 60 mA in 8 bunch mode. There are already 17 insertion devices installed and 9 others are planned in the next 2 coming years. Among them, two canted in vacuum insertion devices are planned, for the Nanoscopium and Tomography beamlines, and will be accommodated in a 12 m long straight section, with a 6.5 mrad separation angle. These ~150 m long beamlines will exploit the high brilliance and coherence characteristics of the X-ray (5-20 keV) beam both for diffraction limited focusing and for contrast formation. To provide low vertical beta functions at each undulator, an extra triplet of quadrupoles was added in the middle of the section. We present here the lattice implementation footprint, the different working point under investigations as well as the first results of the measurements on the machine performances. |
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| WEPEA012 | Status of the SOLEIL Femtosecond X-ray Source | 2499 |
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An electron bunch slicing set-up is being installed on the SOLEIL storage ring, based on Zholents and Zolotorev method [1]. This will provide 100 fs long X-ray pulses with reasonable flux to two existing beamlines, working with soft X-rays (TEMPO) and hard X-rays (CRISTAL). The parameters of the laser system and of the wiggler modulator, and the optimisation of the laser focusing optics and beam path, from the laser hutch in the experimental hall to the inside of the storage ring tunnel have been finalised. The construction work will start early 2010, including the ordering of the laser, the construction of the laser hutch, the construction of the wiggler, the installation of a new modified vacuum dipole chamber by which the laser will enter into the ring, and the modifications of some components in the beamlines front-ends to provide the best possible separation of the sliced X-Ray. In this paper, we will report on the status of the installation of the set-up and the expected performances including laser-electron interaction efficiency, halo background effect and the possible operation filling patterns. |
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| WEPD007 | Development of a PrFeB Cryogenic Undulator at SOLEIL | 3096 |
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The production of hard X rays at SOLEIL, a 2.75 GeV, requires short period and small gap in-vacuum undulators. For shifting further the radiation toward higher energies, the peak magnetic field of the undulators can be further increased by cooling the permanent magnets at cryogenic temperature below 100 K. A R&D programme for the construction of a 2 m long 18 mm period CPMU is launched: the use of PrFeB enables to increase the peak magnetic field at a cryogenic temperature of 77 K. Praseodymium was chosen instead of Neodymium type magnets, because it prevents the appearance of the Spin Reorientation Transition. The magnetic characterisation of different permanent magnet grades at cryogenic temperatures (NdFeB and PrFeB), and the magnetic and thermal measurements on a small 4 period NdFeB cryogenic undulator are presented. The status on the progress of the CPMU conception is given. The magnetic and mechanical design, including the cooling of the girders at 77K, and the thermal budget are described. The designs of the dedicated magnetic measurement benches, which will be required to check the magnetic performance of the undulator at low temperature, are also reported. |
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| WEPD008 | Development of a Short Period High field APPLE-II Undulator at SOLEIL | 3099 |
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At SOLEIL, the production of high brilliant photon beams with adjustable polarization is achieved by means of Advanced Planar Polarized Light Emitter-II (APPLE-II) undulators. The HU36 is a short period high field APPLE-II type undulator with 36 mm period and 0.8 T peak field at a minimum gap of 11 mm. The HU36 circularly polarized radiation ranges from 2 keV to 5 keV, while the planar one extends up to 10 keV. High harmonic radiation (up to the 13th) is required to reach such high energy; therefore a small RMS phase error is needed. To enable closing the gap at 11 mm, the HU36 is planned to be installed in a short section where the large horizontal beta function imposes constraining tolerances on the integrated field errors. However at low period and high field, the magnet holders, commonly used at SOLEIL to maintain magnets on the girders, experience mechanical deformation due to the large magnetic forces. This results in the variation of field integrals when the shift between girders is changed. Solutions to minimize these errors are discussed and finally the HU36 magnetic performances are reviewed. |
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| WEPD009 | Production of High Flux Hard X-ray Photons at SOLEIL | 3102 |
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The production of high fluxes in the hard X-rays region is a major issue on medium energy storage rings. It requires the installation of Insertion Devices with high magnetic field and a large number of periods. The construction of a superconducting wiggler has been first envisaged but reveals to be maintenance constraining, much more complex and expensive than the permanent magnet technology. A small gap in vacuum wiggler composed of 38 periods of 50 mm has been preferred. The compact magnetic system allows to produce in a limited space a magnetic field of 2.1 T in a small gap of 5.5 mm, whereas an auxiliary counterforce system based on non-magnetic springs compensate the magnetic forces (up to 8.5 Tons) acting between magnet arrays. The gap between jaws and the mechanical deformations have been controlled and corrected. Magic fingers corrections have been also performed to reduce the integrated multipoles and to minimize the 2nd order integrals resulting from the tight width of the wiggler poles. This paper presents the design of the wiggler, the construction, and the results of the measurements after magnetic corrections. |