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Title |
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| WEPC048 |
Experimental Characterization of the Insertion Device Effects on Beam Dynamics at SOLEIL
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2097 |
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- P. Brunelle, C. Benabderrahmane, F. Briquez, O. V. Chubar, O. Marcouillé, F. Marteau, A. Nadji, L. S. Nadolski
SOLEIL, Gif-sur-Yvette
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SOLEIL, the French 2.75 GeV third generation light source, has been delivering photons to beam lines in routine operation since January 2007. The storage ring is presently equipped with eleven insertion devices: 3 in-vacuum 20mm period undulators (U20), 1 Apple-II type 52mm period undulator (HU52), 3 Apple-II type 80mm period undulators (HU80), 3 electromagnetic 256mm period undulators (HU256) and 1 electromagnetic 640mm period 10m long undulator (HU640). Commissioning of insertion devices consists of characterizing all the effects on beam dynamics in terms of focussing, injection efficiency, beam lifetime and sensitivity to working point, and also in optimizing feedforward tables in order to compensate for closed orbit distortions during field variations (this last point is detailed in other papers). We will focus here on the significant effects observed with some undulators. Measurements, using electron beam, of the transverse variation of field integrals, were helpful to understand bad effects impacting the daily operation. The introduction of real magnetic characteristics in the lattice model is in progress in order to further optimize the working point.
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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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