A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Ha, K. M.

Paper Title Page
WPPA13 Upgrade of Corrector Power Supplies for Pohang Light Source 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.  
WPPA16 Upgrade of BPM Data Acquisition System Using Reflective Memory at PLS 348
  • J. Choi, K. M. Ha, H.-S. Kang, E.-H. Lee, J. C. Yoon, J. W. Lee
    PAL, Pohang, Kyungbuk
  We upgraded the BPM data acquisition system of the PLS 2.5-Gev storage ring with the use of RFM (Reflective Memory). Our present BPM data acquisition system is based on EPICS VME IOC. It uses an analog-to-digital converter with 16-bit resolution and a 100-KHz conversion rate to digitize BPM raw electric signals. To get better position data from the digitized raw BPM data, we developed BPM data-averaging software utilizing RFM. With this averaging software, we could average 4000 samples of raw BPM data with the refresh rate of 2 seconds and get much better position data compared with the previous one. We installed data-averaging software and reflective memory modules into 12 local BPM IOCs for the routine operation. We are also planning to develop a fast global feedback system using RFM to improve beam quality in the near future.