Author: Chen, S.
Paper Title Page
Status of Dalian Coherent Light Source  
  • W.Q. Zhang, D.X. Dai, G.L. Wang, G.R. Wu, X.M. Yang
    DICP, Dalian, People's Republic of China
  • S. Chen, C. Feng, D. Wang, M. Zhang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  Funding: DCLS is a joint project of Dalian Institute of Chemical Physics (DICP) and Shanghai Institute of Applied Physics (SINAP), CAS. It is supported by National Natural Science Foundation of China (21127902)
A Free Electron Laser with high brightness, ultrafast laser pulses in the vacuum ultraviolet (VUV) wavelength region is an ideal light source for excitation of valence electrons and ionization of molecular systems with very high efficiency. it is quite helpful for studies of important dynamic processes in physical, chemical and biological systems. Dalian Coherent Light Source (DCLS) plans to deliver optical beam from 50-150nm in picoseconds or 100 femtoseconds for such research. High gain harmonic generation is the perfect choice in VUV FEL for narrow bandwidth, stable power and low cost due to fewer undulators. After eight months of installation and machine commissioning, a 300-MeV electron beam was achieved with peak current of more than 300A, and the emittance was less than 1.5 mm.mrad. The FEL power for individual pulse at 133nm approached more than 200uJ with 266nm seed laser on Jan. 2017. The gain curve and spectrum of HGHG & SASE FEL was measured, and tapering undulator helps increase the power by almost 100% when the FEL output saturated. The user experiment will start on June 2017. It is open for good proposals from the whole world.
Design Study of FEL-2 for Dalian Coherent Light Source  
  • G.L. Wang
    DICP, Dalian, People's Republic of China
  • S. Chen
    SINAP, Shanghai, People's Republic of China
  Dalian Coherent Light Source (DCLS) is a free electron laser (FEL) user facility working at 50-150 nm, and is now in user operation with its first FEL line, FEL-1. In this paper, we present a design study of the second FEL line, FEL-2, a polarization controllable and femtosecond FEL. The main components including the switchyard and undulator system are considered and a possible schematic of the switchyard is presented to divert the beam and guarantee the beam properties will not be spoiled. The FEL-2 will be based on the principle of High-Gain Harmonic Generation (HGHG), and the radiator system is composed of 2 planer undulators and 3 helical afterburners. With the help of 3D simulation codes, we show the detailed performance of FEL-2 with the realistic parameters of DCLS.  
Design Study and Preparations for the Echo-30 Experiment at SXFEL  
  • C. Feng, S. Chen, H.X. Deng, B. Liu, D. Wang, X.T. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • D. Xiang
    Shanghai Jiao Tong University, Shanghai, People's Republic of China
  In this work, design study and hardware preparations for the echo-30 experiment at the SXFEL test facility are presented. With the realistic parameters of the SXFEL, start-to-end simulations considering various three-dimensional effects have been carried out, and the simulation results demonstrate that a single-stage EEHG can generate high-power soft x-ray radiation pulses with narrow bandwidth directly from UV seed lasers. We also show the preparations of the seed lasers, undulators and photon beam diagnostics for the echo-30 experiment at the SXFEL.  
Design of the Beam Distribution System for a Soft X-Ray FEL User Facility in Shanghai  
  • S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang
    SINAP, Shanghai, People's Republic of China
  A soft X-ray user facility will be upgraded from an existing soft X-ray test facility in Shanghai. One or more extended FEL undulator lines will be constructed parallel to the previous undulator line. For simultaneous operation of several undulator lines, a beam distribution system is required for spreading the electron bunches from linac to each undulator lines. In this work, the physics design of such a beam distribution system will be described.