| Paper | Title | Page |
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| TUXB01 | Methods and Tools to Simulate and Analyse Non-linear Dynamics in Electron Storage Rings | 937 |
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| This talk will present the different approaches and tools that have been recently developed while trying to understand or predict the non-linear dynamics of electron storage rings. Different algorithms have been recently used at different places to optimize the sextupole tunings, while the refinement of the models of existing machines together with more accurate measurement techniques enable now to fully understand the limitations of such facilities specially in the presence of insertion devices. | ||
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Slides TUXB01 [7.624 MB] | |
| WEPC050 | New Optics for the SOLEIL Storage Ring | 2124 |
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SOLEIL, the French 2.75GeV synchrotron light source is delivering photons to 24 beam lines and is presently equipped with 22 insertion devices (ID) including a high field and small gap in-vacuum wiggler*. This paper presents the continuous work performed to reduce the strong non linear effects of several IDs. On one side, the ID defaults have been precisely identified using on-beam measurements, and magnetic correction developments are going on, especially for the in-vacuum wiggler and for the 10m long HU640 undulator. On the other side, a new optics has been optimised in terms of beta-functions (at the ID location) and non linear dynamics in order to improve the injection efficiency and the beam lifetime in the presence of IDs. The modified optics has been used daily in operation since November 2010 and ensures a beam lifetime greater than 10h for a 400mA stored beam with the users ID configuration. In parallel, an extensive experimental optimization has been performed to prepare the operation with an additional quadrupole triplet that provides double low vertical beta functions in one long straight section that will accommodate two canted in-vacuum insertion devices**.
* O. Marcouillé et al., IPAC10, p. 3102 (2010). ** A. Loulergue et al., IPAC10, p. 2496 (2010). |
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| THPC005 | First Measurements with a Kicked Off Axis Bunch for Pseudo Single Bunch Mode Studies at SOLEIL | 2912 |
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At SOLEIL, the time resolved French community benefits of single bunch operation few weeks a year. Meanwhile most of the multi-bunch filling pattern based experiments are not possible due to the low photon flux. Following the pioneer work performed at ALS*, a new operation mode is under study at SOLEIL where the storage ring is filled up with a special hybrid mode: ¾ multibunch filling pattern and a single bunch with higher current in the last ¼. The so-called pseudo single bunch-filling pattern is obtained if the closed orbit of the single bunch is not the same as the one of the other bunches. Preliminary results are presented where the pinger magnet time impulse response has been significantly reduced while its frequency was increased from 3 Hz up to 1 kHz. This magnet is used as an additional corrector magnet to change only the single bunch closed orbit. First experimental results observed at one interested beamline are also discussed.
* S. Kwiatkowski et al., “'CAMSHAFT' Bunch Kicker Design for the ALS Storage Ring", Proc. of EPAC2006, THPLS114, p. 3547, (2006). |
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| THPC006 | Experiments to Measure Electron Beam Energy using Spin Depolarization Method on SOLEIL Storage Ring | 2915 |
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| The electron beam energy on SOLEIL storage ring was successfully measured using spin depolarization method after several attempts over the past few years. The experimental results demonstrate that the effective polarization was 91.3%±3% and polarization time was 17±2.3 minutes as expected from the simulation using SLIM code. The beam was depolarized using an AC shaker and the depolarization was monitored using DCCT and beam loss monitors. The beam energy was measured with accuracy up to a few 10-5. | ||
| THPC044 | Operation and Performance Upgrade of the Soleil Storage Ring | 3002 |
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| SOLEIL delivers photons to 24 beamlines. Up to 22 very diverse insertion devices (IDs) are now installed on the storage ring, and 4 more will come by summer 2011, including a Cryogenic undulator and an electromagnetic/permanent magnet helical undulator, both designed and built at SOLEIL. Work is continuing on beam dynamics and magnetic corrections to reduce the nonlinear effects of all these IDs. A new optics incorporating an additional quadrupole triplet in one long straight section has been successfully tested and will be put in operation by fall 2011. A new coupling correction will also be implemented to maintain the ratio of the vertical to the horizontal emittances at 1% for any IDs configuration. The electron beam orbit stability has been significantly improved reaching a residual noise of 300 nm RMS. Photon LIBERA modules of X-BPM located on the bends, will be integrated soon in the orbit feedback loops. 4905 hours have been delivered in 2010 to the beamlines with an availability of 96.3%. The user operation with the maximum current of 500 mA is foreseen to start by fall 2011, after the completion of the radiation safety tests of the beamlines. | ||
| TUPC068 | SOLEIL Beam Orbit Stability Improvements | 1156 |
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| The electron beam orbit stability has been significantly improved at synchrotron SOLEIL. Low frequency noise sources have been localized and identified: the fans installed on the storage ring to cool down the ceramic chambers of the kickers, shaker and FCT, were slightly wobbling the electron beam orbit at 46, 50, 54 and 108 Hz. The localization method and the solutions that will allow reducing the noise from 0.8 μm RMS down to 0.3 μm are presented. Besides, a new 160 m long beamline, NANOSCOPIUM, is being installed on a canted straight section. Its photon beam position stability requirements are very tight calling for the following improvements: addition of 2 more BPMs and fast correctors in the orbit feedback loops, new INVAR stands for BPM and XBPM integrating Hydrostatic Level System sensors. The paper is also discussing other projects that did or will contribute to improving the beam orbit stability: installation of 145 temperature sensors on the storage ring, a new analog feedforward correction system for insertion devices, and the use of the bending magnet X-BPM measurements in the slow and fast orbit feedback loops. | ||
| THPO001 | Design Power Supply Considerations to Compensate Booster Power Supply Effects on the SOLEIL Storage Ring | 3335 |
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| Top-up injection mode has been routinely in operation since March 2009 for various bunch filling patterns at Synchrotron SOLEIL. The electron beam stored current is maintained within 1%. At each injection the 3 Hz booster power supplies are ramped up and down over 10 seconds every 3 minutes in average. During this time DC and AC perturbations are observed on the storage ring horizontal closed orbit. Typically, the beamline source points can be shifted up to 10-20 μm and the amplitude of the 3Hz frequency is multiplied by a factor 9. The origin of these perturbations lies in the imperfect compensation of the magnet currents circulating along the booster ring located inside the storage ring. To compensate these disturbances, a wire loop was installed in the booster cable tray fed by an in-house developed power supply. Its output current is driven by direct measurement of the main currents of the booster dipole, quadrupole, sextupole power supplies with a proper amplitude and phase shift. This paper presents the determination of the compensation needs according to beam measurements, the original design and the performance reached when this power supply is acting. | ||