Author: Feng, C.
Paper Title Page
MOZGBD5 A Proposal for Coherent Hard X-Ray Generation Based on Two-Stage EEHG 38
 
  • Z.T. Zhao, J.H. Chen, C. Feng, Z. Wang, K.Q. Zhang
    SINAP, Shanghai, People's Republic of China
 
  A two stage echo-enabled harmonic generation (EEHG) scheme to produce coherent hard X-rays is presented. Electron bunchs of quite different lengths are separately used in each stage of EEHG and a monochromator is employed to purify the radiation from the first stage for seeding the second one. Theoretical analysis and 3D simulations show that the proposed scheme can generate fully coherent hard X-ray pulses directly from a conventional UV seed laser.  
slides icon Slides MOZGBD5 [7.335 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBD5  
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THPMK069 Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai 4456
 
  • S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang
    SINAP, Shanghai, People's Republic of China
 
  A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK069  
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THPMK070 Optimization for the Two-Stage Hard X-Ray Self-Seeding Scheme the SCLF 4460
 
  • T. Liu, C. Feng, D. Wang, X. Wang, K.Q. Zhang
    SINAP, Shanghai, People's Republic of China
 
  Funding: Work supported by the National Natural Science Foundation of China 11475250 and 11605277, National Key Research and Development 2016YFA0401901 and Youth Innovation Promotion Association CAS 2015209.
Self-seeding mode has been demonstrated a great advantage for the achievement of a high brightness X-ray with a pure spectrum. Single-bunch self-seeding scheme with wake monochromators is adopted for the realization of the hard X-ray FEL at the Shanghai Coherent Light Facility (SCLF). Limited by the heat-loading of the monochromator, the two or multiple stages self-seeding scheme is required. In this contribution, we present a basic two-stage scheme design and optimization for the generation of the photon energy range of 3 keV to 15 keV at the line FEL-I of the SCLF. Simulation results show the peak power and pulse energy each stage, which illustrates the loaded energy required of the crystal monochromator as a pointcut of its following thermal analysis. The electron beam energy used in the study is 8 GeV and the central photon energy is 12.4 keV.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK070  
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THPMK075 A Possible Scheme for Generating High-harmonic Coherent Radiation in Storage Rings 4473
SUSPF009   use link to see paper's listing under its alternate paper code  
 
  • X.F. Wang, C. Feng, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
 
  A possible scheme for storage ring FEL which can introduce small energy dispersion and emittance simultaneously to generate intense coherent light in the storage rings is described. Based on a modified version of echo-enabled harmonic generation from free-electron lasers, the technique uses a dogleg and a wave-front tilted seed laser, one normal seed laser and two chicanes to make three-dimensional manipulation of the electron beam phase space, producing high-harmonic microbunching of a relativistic electron beam. Due to small energy dispersion and emittance growth, the storage rings do not need long damping time to recover the quality of the electron beams, so this scheme will significantly improve the performance of FELs based on rings. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in Shanghai Synchrotron Radiation Facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK075  
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THPMK077 The Preliminary Experiment Studies for Soft X-Ray Self-Seeding System Design of SCLF Facility 4481
 
  • K.Q. Zhang, C. Feng, D. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
 
  The preliminary experiment studies for soft x-ray self-seeding system design of SCLF facility have been pre-sented in this paper. Some practical problems and pre-engineering design have been studied for the experimental prepare of soft x-ray self-seeding for the future SCLF facility. The monochromator system designs in this paper include optical structure, optical parameters and mechanical design. The designed optical system has an optical resolution of 1/10000 at the photon energy of 700-1300eV based on the optical simulation. To make the system satisfy the experimental requirements, mechanical install requirements and install precisions are also analysed. Considering the actual varies errors, the errors analyses such as the surface errors of the optical mirror and the machining errors of the VLS grating are also carried out. In conclusion, preliminary experimental studies including system design and varies engineering requirements are introduced to make sure that the presented design is reliable for final soft x-ray self-seeding experiment of SCLF facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK077  
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THPMK078 Corrugated Structure as a Linearizer in High Repetition Rate X-Ray Free Electron Laser Source 4485
 
  • Z. Wang, C. Feng, D. Huang, K.Q. Zhang, M. Zhang
    SINAP, Shanghai, People's Republic of China
 
  A feasible method is proposed to compensate the high order mode (HOM) of the RF field, linearize the bunch compression process in the high repetition rate x-ray free electron laser source. In the proposed scheme, the corrugated structure is used in the superconducting linac to linearize the longitudinal phase space of the electron beam. The results show that the peak current of the electron beam will be increased from about 1 kA to over 2 kA with the charge of 100 pC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK078  
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