Author: Marlats, J.L.
Paper Title Page
WEPC169 BPM System Interlock for Machine Protection at SOLEIL 2379
 
  • J.-C. Denard, C. Herbeaux, M. Labat, V. Leroux, A. Loulergue, J.L. Marlats
    SOLEIL, Gif-sur-Yvette, France
 
  SOLEIL, a third generation light source, has its Beam Position Monitors (BPM) processed by the LIBERA electronics built by Instrumentation Technologies. This electronics initiated and specified by SOLEIL features a fast hardware interlock output for machine protection. Although interlocks are available in both horizontal and vertical planes, it was initially thought that only the vertical interlocks would be useful. Actually, the high photon beam power densities (up to 1kW/mm2) generated by the in-vacuum undulators could damage vacuum chamber elements in case of corrector power supply failures in horizontal or vertical plane. Crotch absorbers, XBPMs and their upstream absorbers were designed on the basis that they will be protected with interlock thresholds not tighter than ±1mm. This approach was also applied for specifying the apertures of the XBPMs and of their upstream absorbers. More recently tracking simulation has shown that the crotch absorber apertures downstream the new canted undulators needed special attention.  
 
THPC140 Design, Tuning and Results of the Pulsed Magnetic Systems for the Beam Injection in the SOLEIL Storage Ring Operated in ‘Transparent’ Top Up Mode 3215
 
  • P. Lebasque, R. Ben El Fekih, M. Bol, J. Da Silva Castro, A. Hardy, C. Herbeaux, J.-P. Lavieville, A. Loulergue, J.L. Marlats, D. Muller, G. Renaud, J.P. Ricaud
    SOLEIL, Gif-sur-Yvette, France
 
  From the beginning, the SOLEIL Storage Ring was designed to operate in Top Up injection mode. So all equipments involved have been specified to generate as small as possible beam perturbations of the stored beam during the electron beam injection. This concerns many aspects of the design and realization of the injection pulsed magnets (kickers and septa), their vacuum chambers, pulsed power supplies and timing electronics. Despite quite satisfactory results of pulsed magnetic measurements in labs, a still too large perturbation was observed on the e- beam orbit during the Storage Ring commissioning. Therefore a strong work of systematic measurements, analysis of each phenomena, tuning or modification of each device was led until reaching rather good and acceptable performances. This paper will present the results obtained. At this stage, the Storage Ring beam orbit is sufficiently stable in Top Up injection mode so that it is almost transparent to the 24 beam lines, even for the most sensitive ones. After a summary of the main significant topics, we present the developments foreseen to further improve the performances and make a new step towards a “perfect” Top Up injection.  
 
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 IDBuilder software and the trajectory were checked for insuring a good reproducibility of the photon beam pointing when sweeping from one helicity to the other.  
 
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.