IPAC2011 - List of Authors (Filhol, J.-M.)

Paper	Title	Page
MOPS049	Study of Ion-induced Instabilities and Transverse Feedback Performance at SOLEIL	712
	R. Nagaoka, L. Cassinari, M.D. Diop, J.-M. Filhol, M.-P. Level, A. Loulergue, P. Marchand, R. Sreedharan SOLEIL, Gif-sur-Yvette, France
	Experimental studies indicate that the SOLEIL storage ring at its maximum designed current of 500 mA is under a large influence of ions, potentially capable of inducing the so called fast beam-ion instability. To avoid it, the following three conditions have been empirically found effective: A reduced RF voltage, uniform filling and a large vertical chromaticity. While the choice of uniform filling appears contradictory to raising the ion instability threshold, it goes well with lowering of the RF voltage if outgassing due to beam-induced heating of the vacuum components is the primary source of ions. Additional difficulties associated are frequent occurrence of sudden beam blowups despite the presence of transverse feedback, which are large enough to trigger machine interlocks leading to complete beam losses. These blow ups may even take place horizontally inside in-vacuum insertion devices. The present paper reports on the results and findings obtained through experimental and simulation studies carried out on the collective beam dynamics and the transverse feedback performance, which are deeply interlinked, in order to clarify the mechanism of the encountered phenomena.

THPC044	Operation and Performance Upgrade of the Soleil Storage Ring	3002
	A. Nadji, P. Brunelle, M.-E. Couprie, J.-C. Denard, J.-M. Filhol, J.-F. Lamarre, P. Lebasque, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	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.

THPC149	Development of PrFeB Cryogenic Undulator (CPMU) at SOLEIL	3233
	C. Benabderrahmane, P. Berteaud, N. Béchu, L. Chapuis, M.-E. Couprie, J.P. Daguerre, J.-M. Filhol, C. Herbeaux, A. Lestrade, M. Louvet, J.L. Marlats, K. Tavakoli, M. Valléau, D. Zerbib SOLEIL, Gif-sur-Yvette, France
	A R&D programme for the construction of a 2 m long 18 mm period CPMU is under progress at SOLEIL. The cryogenic undulator will provide photons in the region of 1.4 to 30 keV. It will be installed in the next few months on the long straight section (SDL13) of the storage ring, and could be used later on to produce photons for the NANOSCOPIUM beamline. The use of PrFeB which features a 1.35 T remanence (Br) at room temperature enables to increase the peak magnetic field at 5.5 mm minimum gap, from 1.04 T at room temperature to 1.15 T at a cryogenic temperature of 77 K. Praseodymium was chosen instead of Neodymium magnetic material, because it is more resistant against the appearance of the Spin Reorientation Transition. Different corrections were performed first at room temperature to adjust the phase error, the electron trajectory and to reduce the multipolar components. The mounting inside the vacuum chamber enables the fitting of a dedicated magnetic measurement bench to check the magnetic performance of the undulator at low temperature. The results of the magnetic measurements at low temperature and the comparison with the measurement at room temperature are reported.

THPC151	The 65 mm Period Electromagnetic/Permanent Magnets Helical Undulator at SOLEIL	3239
	F. Marteau, P. Berteaud, F. Bouvet, L. Chapuis, M.-E. Couprie, J.P. Daguerre, T.K. El Ajjouri, J.-M. Filhol, P. Lebasque, J.L. Marlats, A. Mary, K. Tavakoli SOLEIL, Gif-sur-Yvette, France
	SOLEIL prepares a new 65 mm period Electromagnetic/Permanent Magnets Helical Undulator (EMPHU), with a rapid switching at 5 Hz of the polarization required for dichroïsm experiments. The vertical field Bz is produced by coils fed by a fast switching power supply (designed and built in house), with a maximum current of 350 A and a polarity switching time shorter than 100 ms. The coils consist of 25 stacked copper layers shaped by water jet cutting. The current flows in 16 layers and 9 of them are cooled with thermal drain to a water piping. 4 additional power supplies feed 2 types of correction coils for the dynamic compensation of the field integrals, besides the ones for the termination. 1.28 T remanence NdFeB permanent magnets generate the horizontal field Bx. Peak Bz and Bx in the helical configuration reach 0.24 T at 14.7 mm minimum gap. Thermal modelling and measurements aim at keeping the magnet temperature constant. The static magnetic configuration was optimised using the ID_Builder software and the trajectory were checked for insuring a good reproducibility of the photon beam pointing when sweeping from one helicity to the other.

Paper

Title

Page

Study of Ion-induced Instabilities and Transverse Feedback Performance at SOLEIL

712

R. Nagaoka, L. Cassinari, M.D. Diop, J.-M. Filhol, M.-P. Level, A. Loulergue, P. Marchand, R. Sreedharan
SOLEIL, Gif-sur-Yvette, France

Experimental studies indicate that the SOLEIL storage ring at its maximum designed current of 500 mA is under a large influence of ions, potentially capable of inducing the so called fast beam-ion instability. To avoid it, the following three conditions have been empirically found effective: A reduced RF voltage, uniform filling and a large vertical chromaticity. While the choice of uniform filling appears contradictory to raising the ion instability threshold, it goes well with lowering of the RF voltage if outgassing due to beam-induced heating of the vacuum components is the primary source of ions. Additional difficulties associated are frequent occurrence of sudden beam blowups despite the presence of transverse feedback, which are large enough to trigger machine interlocks leading to complete beam losses. These blow ups may even take place horizontally inside in-vacuum insertion devices. The present paper reports on the results and findings obtained through experimental and simulation studies carried out on the collective beam dynamics and the transverse feedback performance, which are deeply interlinked, in order to clarify the mechanism of the encountered phenomena.

THPC044

Operation and Performance Upgrade of the Soleil Storage Ring

3002

A. Nadji, P. Brunelle, M.-E. Couprie, J.-C. Denard, J.-M. Filhol, J.-F. Lamarre, P. Lebasque, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

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.

THPC149

Development of PrFeB Cryogenic Undulator (CPMU) at SOLEIL

3233

C. Benabderrahmane, P. Berteaud, N. Béchu, L. Chapuis, M.-E. Couprie, J.P. Daguerre, J.-M. Filhol, C. Herbeaux, A. Lestrade, M. Louvet, J.L. Marlats, K. Tavakoli, M. Valléau, D. Zerbib
SOLEIL, Gif-sur-Yvette, France

A R&D programme for the construction of a 2 m long 18 mm period CPMU is under progress at SOLEIL. The cryogenic undulator will provide photons in the region of 1.4 to 30 keV. It will be installed in the next few months on the long straight section (SDL13) of the storage ring, and could be used later on to produce photons for the NANOSCOPIUM beamline. The use of PrFeB which features a 1.35 T remanence (Br) at room temperature enables to increase the peak magnetic field at 5.5 mm minimum gap, from 1.04 T at room temperature to 1.15 T at a cryogenic temperature of 77 K. Praseodymium was chosen instead of Neodymium magnetic material, because it is more resistant against the appearance of the Spin Reorientation Transition. Different corrections were performed first at room temperature to adjust the phase error, the electron trajectory and to reduce the multipolar components. The mounting inside the vacuum chamber enables the fitting of a dedicated magnetic measurement bench to check the magnetic performance of the undulator at low temperature. The results of the magnetic measurements at low temperature and the comparison with the measurement at room temperature are reported.

THPC151

The 65 mm Period Electromagnetic/Permanent Magnets Helical Undulator at SOLEIL

3239

F. Marteau, P. Berteaud, F. Bouvet, L. Chapuis, M.-E. Couprie, J.P. Daguerre, T.K. El Ajjouri, J.-M. Filhol, P. Lebasque, J.L. Marlats, A. Mary, K. Tavakoli
SOLEIL, Gif-sur-Yvette, France

SOLEIL prepares a new 65 mm period Electromagnetic/Permanent Magnets Helical Undulator (EMPHU), with a rapid switching at 5 Hz of the polarization required for dichroïsm experiments. The vertical field Bz is produced by coils fed by a fast switching power supply (designed and built in house), with a maximum current of 350 A and a polarity switching time shorter than 100 ms. The coils consist of 25 stacked copper layers shaped by water jet cutting. The current flows in 16 layers and 9 of them are cooled with thermal drain to a water piping. 4 additional power supplies feed 2 types of correction coils for the dynamic compensation of the field integrals, besides the ones for the termination. 1.28 T remanence NdFeB permanent magnets generate the horizontal field Bx. Peak Bz and Bx in the helical configuration reach 0.24 T at 14.7 mm minimum gap. Thermal modelling and measurements aim at keeping the magnet temperature constant. The static magnetic configuration was optimised using the ID_Builder software and the trajectory were checked for insuring a good reproducibility of the photon beam pointing when sweeping from one helicity to the other.