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insertion-device

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WPPA13 Upgrade of Corrector Power Supplies for Pohang Light Source power-supply, feedback, controls, insertion 342
 
  • J. Choi, K. M. Ha, J. Y. Huang, S.-H. Jeong, H.-S. Kang, S.-C. Kim, J.-H. Suh, I. S. Ko
    PAL, Pohang, Kyungbuk
  There are 70 vertical and 70 horizontal correctors for Pohang Light Source. Until 2003, power supplies for these correctors were based on 1980’s technology, so the global orbit feedback system was not possible with poor 12-bit resolution. In 2003, a task force team was assembled to develop new power supplies with BESSY type ADC cards. By Summer 2004, two vertical correctors in each lattice were connected with new power supplies, and the global orbit feedback was available within the accuracy of 5 microns. However, this replacement was not enough to satisfy the beam stability requirement of 2 microns for PLS. We have launched another power supply design based on all digital technology. This attempt was completed within a year, and 80 units were assembled in house. Currently, the global orbit feedback system is running successfully with new digital power supplies and the compensation of chamber motion due to the thermal load by using digital displacement transducers attached on each BPMs.  
 
RPPA10 Status of the Diamond Fast Orbit Feedback System feedback, controls, power-supply, insertion 535
 
  • M. G. Abbott, J. A. Dobbing, M. T. Heron, I. P.S. Martin, G. Rehm, I. Uzun, J. Rowland
    Diamond, Oxfordshire
  • S. Duncan
    University of Oxford, Oxford
  We present the development of transverse orbit stability control at Diamond. We discuss the low latency feedback loop required to effectively suppress high-frequency noise, which informs the choice of network topology and processing units. We explore the use of the field-programmable gate array in the Libera beam position monitor as a communication controller and the vector unit of the PowerPC G4 in the compensator. System models and results from preliminary tests on the machine are shown.  
 
RPPA29 A Feed-Forward Procedure to Counteract Orbit Distortions and Photon Beam Displacements from Insertion Device Operation at the SLS photon, insertion, electron, undulator 573
 
  • T. Schmidt, A. Streun, D. Zimoch, J. T.M. Chrin
    PSI, Villigen
  Insertion devices of various types provide light of high brilliance to experimenters at the SLS beamlines. Changes in the photon energy and polarization by movement of the ID gap and phase shift, however, cause orbit distortions that result in a displacement of the photon beam in both angle and position at the beamline. A feed-forward correction scheme has been developed to quantify and precisely correct these effects using designated correctors local to the photon source. The corrector settings are determined using an orbit configuration consisting of 73 digital BPMs and associated correctors; recently commissioned X-ray BPMs located at the beamline front-end are also included in the correction algorithmn and serve to constrain the photon beam to its specified position. The feed-forward table is finally implemented at the local processor level and applied at a rate of 10 Hz. A photon pointing stability at the sub-microradian level is achieved. The entire gap scan, feed-forward generation and subsequent verification can now be completed within 15 to 60 minutes depending on the complexity of the ID. The methodology of the procedure and high-level software framework is described.