Author: Kim, C.
Paper Title Page
MOPMB058 Bunch Arrival Time Monitor Test at PAL-XFEL ITF 223
  • J.H. Hong, J.H. Han, C. Kim, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
  Femtosecond resolution electron bunch arrival time monitor (BAM) will be required for the beam-based RF phase feedback during PAL-XFEL operation. Two S-band cavity-type BAMs were manufactured for the test at the PAL-XFEL injector test facility (ITF). The resonance frequencies of the cavities are 2856 MHz and 2826.25 MHz. Electron beam induced signal from the cavities was digitized using a low level RF (LLRF) module. In this paper, the resolution of these cavities are analyzed and a possible improvement for better resolution are discussed.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB058  
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MOPMR001 Micro-mover Development and Test in the PAL-XFEL 229
  • B.G. Oh, J.H. Han, H. Heo, J.H. Hong, H.-S. Kang, C. Kim, D.E. Kim, K.-H. Park, Y.J. Suh
    PAL, Pohang, Republic of Korea
  Two micro-movers, which are able to control the horizontal, vertical and longitudinal positions as well as the yaw and pitch angles remotely, were developed and installed in the PAL-XFEL linac. The solenoid micro-mover in the gun section allows beam-based alignment of an electron beam to the solenoid field and the gun RF field. The X-band cavity micro-mover minimizes the transverse wake field effect caused by transverse misalignment between the beam and X-band cavity. Two micro-movers has similar specifications and the same mechanism, but the sizes are different from each other. In this paper, we present the design, manufacture and test results of the micro-movers.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR001  
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WEYB01 Diagnostic Systems of the PAL-XFEL 2091
  • C. Kim, S.Y. Baek, H. J. Choi, J.H. Hong, H.-S. Kang, G. Kim, J.H. Kim, I.S. Ko, S.J. Lee, G. Mun, B.G. Oh, B.R. Park, D.C. Shin, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
  The Pohang Accelerator Laboratory (PAL) started an x-ray free electron laser project (PAL-XFEL) in 2011. The construction was finished at the end of 2015 and the commissioning is planned from the beginning of 2016. In the PAL-XFEL, an electron beam with 200 pC will be generated from a photocathode RF gun and will be accelerated to 10 GeV by using a linear accelerator. The electron beam will pass through undulator section to produce hard X-ray radiation. For the successful commissioning and beam operation, various kinds of instruments were prepared.  
slides icon Slides WEYB01 [11.770 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEYB01  
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WEPOR004 Fast Orbit Feedback System at the Pls-Ii Storage Ring 2667
  • S.-C. Kim, W.S. Cho, C. Kim, J.M. Kim, K.R. Kim, E.H. Lee, J. Lee, J.W. Lee, T.-Y. Lee, C.D. Park, G.S. Park, S. Shin, J.C. Yoon
    PAL, Pohang, Kyungbuk, Republic of Korea
  Funding: This work is supported by the Ministry of science, ICT and Future Planning, Korea.
The transverse position of the electron beam in the Pohang Light Source-II (PLS-II) is stabilized by the global orbit feedback system. Currently, 2 Hz slow orbit feedback (SOFB) system is operating, and 1 kHz fast orbit feedback (FOFB) system is installed recently. This FOFB system is consists of 96 electron beam position monitors (BPMs), 48 horizontal fast correctors, 48 vertical fast correctors and VME control system. We present the design and implementation of the FOFB system and its test result. Analysis through the simulation is presented and future improvement is discussed
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR004  
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THPOY057 RF Timing Distribution and Laser Synchronization Commissioning of PAL-XFEL 4234
  • C.-K. Min, S.H. Jung, H.-S. Kang, C. Kim, I.S. Ko, S.J. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
  PAL-XFEL requires <100 fs synchronization of LLRF systems and optical lasers for stable operation and even lower jitter is favorable in higher performance and pump-probe experiments. The RF timing distribution system is based on a 476 MHz reference line, which is converted to 2.856 GHz at 16 locations over 1.5 km distance using phase-locked DRO. The 2.856 GHz signals are amplified and split to 10 outputs, which is connected to LLRFs, BAMs, and DCMs through low timing drift cables. The jitter between two different PLDRO units is estimated to ~1 fs from 1 Hz to 1 MHz. The synchronization jitter between a Ti:sapphire laser and the 2.856 GHz signal is measured less than 20 fs.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY057  
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