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Ha, K. M.

Paper Title Page
MOPAN060 Compensation of BPM Chamber Motion in PLS Orbit Feedback System 290
  • H.-S. Kang, J. Choi, K. M. Ha, E.-H. Lee, W. W. Lee, I. S. Park
    PAL, Pohang, Kyungbuk
  The false BPM reading resulting from the BPM vacuum chamber motion due to thermal load change by synchrotron radiation is compensated by the real-time monitoring of the chamber position in the PLS orbit feedback system. The BPM chamber moves up to 20 μm during the beam refill and the chamber motion has a time constant of about one and half hour, which is related to thermal equilibrium of the vacuum chamber. To monitor the BPM chamber motion, LVDTs with 0.2 μm reading accuracy were installed on all BPM chambers, and the measured data are used in the orbit feedback every 1 minute. In this paper, we will describe how serious the BPM chamber motion are and how well it is compensated.  
MOPAN061 Compact Output Filter for Switching Frequency Elimination at the PLC Linac New Magnet Power Supply 293
  • S.-C. Kim, J. Choi, K. M. Ha, J. Y. Huang
    PAL, Pohang, Kyungbuk
  Funding: This work is supported by the Ministry of Science and Technology, Korea.

At 2006, PLS Linac magnet power supply (MPS) has been upgraded for the stable beam injection and 4th generation light source research. New MPS are developed new compact MPS of 16-bit resolution and 20ppm stability using four-quadrant switching scheme with 50kHz MOSFET switching device, and consists of main power board, control power board, regulator board and CPU board. Size of each board is only 100mm width and 240mm depth. Output of MPS is 10V, ±10A for the bipolar and 50V, 50A for the unipolar magnet. Main board is consisted four-quadrant FET switch, driver and output filter. Output filter must be perfectly eliminating switch frequency and compact size. In this paper, we report on development and characteristics of compact output filter of the new MPS for PAL linac.