Author: Kim, D.
Paper Title Page
MOPP27 EPU-PBPM with CVD-diamond Blade at PLS-II 112
 
  • J. Ko, T. Ha, G. Hahn, D. Kim, S. Shin
    PAL, Pohang, Republic of Korea
 
  All 18 photon beam position monitors (PBPM) installed on the PLS-II are tungsten blade types. The elliptical polarized undulator (EPU) has the characteristic that the spatial profile of the beam varies depending on the polarization mode. This relates to the thermal load of the blade and changes in the blade material at fixed blade gaps are inevitable. In this paper, we analyze power density and flux density according to EPU mode and describe the process of installing PBPM with CVD-diamond blades on the PLS-II beamline for the first time.  
poster icon Poster MOPP27 [1.962 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2021-MOPP27  
About • paper received ※ 20 July 2021       paper accepted ※ 15 September 2021       issue date ※ 15 October 2021  
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WEPP10 Development of an On-Line Bunch Length Monitoring System at PLS-II Using an Ultrafast Photodiode 384
 
  • W.J. Song
    POSTECH, Pohang, Republic of Korea
  • T. Ha, G. Hahn, Y.D. Joo, D. Kim, Y.S. Lee
    PAL, Pohang, Republic of Korea
  • J.-G. Hwang
    HZB, Berlin, Germany
 
  Users of time-resolving experiments at 3rd generation synchrotron light sources deem online bunch length and filling pattern monitoring as an important real-time diagnostic. We developed an on-line monitoring system that can measure bunch lengths and filling pattern using a photodiode, a wideband pre-amplifier, and a sampling digitizer. Two different methods were evaluated to reconstruct the bunch lengths: Gaussian deconvolution method as an approximation scheme and Fourier analysis as a method to restore the original signal by using the power transmission characteristics of the electronic devices in the system, including a bias-tee, a wideband amplifier, cables, and the photodiode. A bunch lengthening experiment has been conducted to compare and verify the results of those two methods of the photodiode and the result of the streak camera images by changing the overall gap voltage of the superconducting RF cavities. In this paper, we elaborate upon the said photodiode-based measurement techniques, and present the experimental results.  
poster icon Poster WEPP10 [0.563 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2021-WEPP10  
About • paper received ※ 08 September 2021       paper accepted ※ 27 September 2021       issue date ※ 07 October 2021  
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