Author: Liu, B.
Paper Title Page
TUPRB046 Second Order Intensity Correlation and Statistical Properties of a Soft X-Ray Free Electron Laser 1788
 
  • C.L. Li, J.H. Chen, Z.C. Chen, X.T. Wang, H.L. Wu
    SINAP, Shanghai, People’s Republic of China
  • B. Liu, T. Liu
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  
  High degree of transverse field coherence is one of the unique properties of an FEL compared with a 3rd gen-eration storage ring light source. As a result, the FEL advances the development of innovative research and technology that was not previously feasible. A truly coherent source should be coherent in all orders de-scribed from the intensity correlation functions. In this paper, second order intensity correlation of FEL radia-tion is investigated based on the Hanbury Brown-Twiss intensity correlation method. The statistical properties of radiation produced from SASE was also investigated and compared with the statistical proper-ties of a phase-locked laser. The results show that the statistical properties of a SASE mode behave as a cha-otic source, which is significantly different from the properties of a phase-locked laser beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB046  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB055 First Results of the IVU16 Prototype Undulator Measurements 1808
 
  • C. Yu, Y.Z. He, X. Hu, Z. Jiang, M.F. Qian, Y.M. Wen, S. Xiang, L. Yin, J.D. Zhang, W. Zhang, Q.G. Zhou
    SINAP, Shanghai, People’s Republic of China
  • H.X. Deng, B. Liu, D. Wang
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • H.F. Wang, Z.T. Zhao
    SSRF, Shanghai, People’s Republic of China
  
  The Shanghai Synchrotron Radiation Facility (SSRF) has developed a 16 mm period length, 4 mm gap, in-vacuum undulator (IVU) that is planned to be installed and tested in the 1.5 GeV SXFEL-SBP beam line. This paper will describe the main parameters of the undulator and the key design choices that have been made. The first undulator prototype was assembled and magnetically tested. First measurements with vacuum chamber will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB055  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB054 The Beam-Based Alignment Simulation and Preliminary Experiment at SXFEL 1804
 
  • L. Zeng, H.X. Deng, C. Feng, D. Gu, B. Liu, Z.T. Zhao
    SINAP, Shanghai, People’s Republic of China
  • G.L. Wang
    DICP, Dalian, People’s Republic of China
  
  The Shanghai soft X-ray Free-electron Laser facility (SXFEL) is now serving as an experimental platform for fundamental free-electron laser (FEL) principle tests. The machine puts very tight tolerance on the straightness of the electron beam orbit. It is hard to achieve the required trajectory due to the off-axis field of the misaligned quadrupoles and undulator segments especially for the SXFEL driven by low energy linac (840MeV). This tight requirement on electron beam straightness can only be met through the beam-based alignment (BBA) technology which achieved great success at LCLS, PAL-XFEL, European-XFEL and SCALA with high electron beam energies. But there has been no report about satisfactory BBA experiment results on soft X-ray FEL facility driven by relatively low energy linacs (on the order of 2 GeV or less) up to now. Here, we report the simulation results and preparatory experiment progress of the BBA at SXFEL with the method of dispersion-free steering (DFS). The experiment results show some improvements of the electron beam orbit and the phenomenon of the dispersion-free. The entire BBA experiment and a feedback system of electron beam trajectory may also be included.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB054  
About • paper received ※ 18 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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THPRB043 Design and Simulation of Thin Eddy-Current Septum for Injection of Diffraction Limited Storage Ring 3908
 
  • J. Tong, M. Gu, B. Liu, Y.F. Liu, R. Wang
    SINAP, Shanghai, People’s Republic of China
  
  Funding: Work supported by the National Key Research and Development Program of China(Grant No.2016YFA0402002)
Ultra-low emittance in Diffraction Limited Storage Ring (DLSR) usually has small Dynamic Aperture (DA), which makes the traditional off-axis injection inadequate. Fast kickers together with thin septum magnets or direct current lambertsons could support on-axis injection for closely-spaced bunches with small DA. Thin eddy-current septum prototype had been designed for injection with laminated silicon steel sheets as magnet core. Theoretical analysis and transient simulation had been carried out within OPERA software. Due to the minimum thickness of the septa is only 1 mm , several optimization approaches had been applied, such as shielding with strongly paramagnetic material and exciting with full cycle driving pulse, to satisfy the requirement that the leakage field is less than 0.1% with respect to the main one. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB043  
About • paper received ※ 29 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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