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Lee, W.W.

Paper Title Page
WEPKF049 Stretched Wire Flip Coil System for Magnetic Field Measurements 1714
 
  • D.E. Kim, C.W. Chung, H.S. Han, Y.G. Jung, H.G. Lee, W.W. Lee, K.-H. Park, H.S. Suh
    PAL, Pohang
  
  A flip-coil system using a stretched wire measuring the magnetic field properties of accelerator magnets is described. This system is similar to the conventional rotating coil system except that the stretched wires are used instead of wires wound on the machined surface. This system has advantage of simple fabrication and flexible operation so that different length and bore magnets can be easily measured using the same system. The system also has two loop coils to buck the dominant fundamental field so as to increase the measurement accuracy. This kind of system has issues related to the reproducibility, accuracy of the measured results. The system is evaluated to verify its performances and its results were discussed. The analyzing methods and various efforts to keep the system in high accuracy are presented. Measurement results with this loop coil system were compared with that of the other system.  
THPLT084 Test Result of Slow Global Orbit Feedback using MATLAB at PLS 2691
 
  • H.-S. Kang, J. Choi, K.M. Ha, E.-H. Lee, T.-Y. Lee, W.W. Lee
    PAL, Pohang
  
  A slow global orbit feedback using MATLAB has been tested to control the slow orbit movement for the PLS. The feedback program uses MATLAB tools such as matrix algebra, mathematical functions, and graphic display, and uses the SVD (singular value decomposition) method. The PLS uses 70 corrector magnets with the maximum angle of 2-mrad for each plane among which 11 use the 16-bit DAC power supplies for the insertion device orbit control and others the 12-bit corrector power supplies with the minimum step of 1-micro-rad, and thus the orbit feedback is not acceptable to beamline users. For the best performance of the feedback, the major hardware components have been upgraded: the replacement of 12-bit BPMs with 16-bit was completed, and the upgrade of corrector power supplies from DAC 12-bit to 18-bit or higher will be completed soon. In this paper, the orbit feedback test result using the current corrector power supplies is presented and the upgrade plan of orbit feedback is described.