Author: Choi, H. J.
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MOPMB057 Automatic Microbeam Focusing for X-Ray Microbeam Experiments at the 4B Beamline of Pohang Light Source-II 220
  • K.H. Gil, H. J. Choi, J.-H. Lim
    PAL, Pohang, Kyungbuk, Republic of Korea
  The 4B beamline of the Pohang Light Source-II performs X-ray microdiffraction and microfluorescence experiments using X-ray microbeams. When performing X-ray micro-experiments, an X-ray microbeam should first be prepared. Up to recently, the microbeams with vertical and horizontal sizes (full width at half maximum) of less than 3 μm have been achieved, by manually adjusting the translations and pitch angles of the vertically and horizontally focusing mirrors, in a Kirkpatrick'Baez (K-B) mirror system. In this research, we developed a program that automates the complex and cumbersome process of microbeam focusing, divided into half-cutting and focusing phases. The developed program was applied to the 4B beamline and enabled the focusing of an X-ray beam to a minimum size within one hour. This paper introduces the algorithms of the program and also examines its performance.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB057  
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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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WEPOR015 Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder 2693
  • H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo
    PAL, Pohang, Kyungbuk, Republic of Korea
  To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR015  
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