| Paper | Title | Page |
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| TUPC069 | Bunch Length Measurements from the Incoherent Synchrotron Radiation Fluctuation at SOLEIL | 1159 |
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Bunch length measurements can be made by analysing the pulse to pulse intensity fluctuation of the incoherent synchrotron radiation as it has been reported elsewhere*. Such a method has been tested at SOLEIL for picosecond bunch durations, at several wavelengths and bandwidths in the visible range, using an avalanche photodiode. Thanks to the low-alpha optics the lengths of 10 μA bunches as short as 3 ps have been measured in good agreement with the streak camera results. We first used the radiation from a bending magnet, and then from a HU640 undulator that enhances the photon flux. Moreover, taking advantage of using the radiation from an undulator, we show that the method can still be used when the number of spikes emitted by the electron bunch is reduced to a few hundreds. This could be of interest for bunch length measurements of X-ray SASE FELs. Furthermore, we intend to use a single crystal diamond detector in order to perform these measurements in the X-ray range.
* F. Sannibale et al., "Absolute bunch length measurements by incoherent radiation fluctuation analysis", PRST AB 12, 032801 (2009). |
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| 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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| THPC150 | Review of Insertion Device Dedicated to HIgh Energy Photons at SOLEIL | 3236 |
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| Producing high energy photons between 10 keV and 70 keV is a challenging topic in a medium energy storage ring. It requires up-to-date measurement techniques and specific Insertion Device (ID) technologies to produce high magnetic fields and short periods. SOLEIL (2.75 GeV) has designed and built eight conventional in-vacuum hybrid undulators operating at high radiation harmonics and also one small gap multipole wiggler to produce high magnetic field. The construction has been progressively improved by the choice of new magnetic materials of better quality and higher magnetization, additional correction techniques and mechanical changes. A 2-m long full scale cryogenic undulator made of PrFeB and vanadium permendur has been built, measured, corrected and is to be tested on the beam. An additional wiggler dedicated for Slicing experiments has been designed. The required magnetic field is high enough to also consider the ID as a good candidate for the production of hard X-ray photons. This paper presents the ID dedicated for the high energy photons and their spectral performances. | ||
| THPC152 | Measurements of SOLEIL Insertion Devices using Pulsed Wire Method | 3242 |
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| SOLEIL permanent magnets insertion devices are usually measured with a Hall probe in order to evaluate the electron angular deflexion, their deviation and the optical phase error, a figure of merit related to the quality of the insertion device radiation. A pulsed wire bench is developed at SOLEIL for reducing the measurement time of an undulator and for providing a measurement method without lateral access. A current pulse injected in a stretched wire inside the magnetic field area generates acoustic wave. The wire motion is detected by optical sensors whose signals are proportional to the local integral value. The signal-to-noise ratio of this method is often reduced due to several effects such as electronic noise, external and wire vibrations. However, following some hardware optimization it was possible to increase it up to almost 26 dB, making the method accurate and reproducible in order to realize efficient corrections. Measurements of first and second integral performed with Pulse wire, with Hall probe and with the electron beam are compared on three different types of insertions: an U18 in-vacuum cryogenic undulator, a HU60 APPLE-II undulator and a WSV50 in-vacuum wiggler. | ||