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Shi, J.

Paper Title Page
TUPMN054 Design of a Source to Supply Ultra-fast Electron and X-Ray Pulses 1046
  • W.-H. Huang, H. Chen, Y.-C. Du, Hua, J. F. Hua, R. K. Li, Y. Lin, J. Shi, C.-X. Tang, D. Xiang, L. X. Yan, P.-CH. Yu
    TUB, Beijing
  In this paper we report the preliminary design and considerations on a multi-discipline ultra-fast source, which is capable of providing the user community with femtosecond electron bunch and light pulses with the wavelength ranging from IR to X-ray. The facility is based on photocathode RF gun driven by a Ti:Sapphire laser system. The low emittance subpicosecond electron bunch at the gun exit can be used in femtosecond electron diffraction setup to visualize the ultrafast structural dynamics. After acceleration and compression, the electron beam with the energy of 50 MeV is further used to provide high peak brightness X-ray by inverse Compton scattering with TW laser. We also consider the possibility and reliability of storing the electron beam in a compact storage ring and the laser pulse in a super-cavity. Operating in this scheme may increase the average flux of the X-ray photons by orders of magnitude.  
THPAS045 Method of Perturbative-PIC Simulation for Interactions between a Bunch and Its Synchrotron Radiation 3594
  • J. Shi
    KU, Lawrence, Kansas
  • G. Hoffstaetter
    CLASSE, Ithaca
  Funding: This work is supported by the US Department of Energy under Grant No. DE-FG02-04ER41288.

A self-consistant simulation method is developed for the study of coherent synchrotron radiation effects by using a perturbation expansion of retarded radiation field and the particle-in-cell method. The perturbation expansion of the radiation field is based on the fact that the time dependance of a bunch particle distribution has typically two significantly different time scales, a fast time scale related to the linear dynamics and a slow time scale of the beam-size growth due to nonlinear perturbations. Since the scale of the retardation of the radiation field is usually much shorter than the slow time scale of the particle distribution, the retardation on the slow time scale of the particle distribution is treated perturbatively while the retardation on the fast time scale is removed by transformations associated the linear lattice. With this method, the particle-radiation interaction can be calculated in configuration space without memorizing the history of the particle distribution.

THPAN054 Experiment on a Cold Test Model of a 2-Cell SC Deflecting Cavity for ALS at LBNL 3348
  • J. Shi, H. Chen, C.-X. Tang, S. Zheng
    TUB, Beijing
  • D. Li
    LBNL, Berkeley, California
  Deflecting Cavities can be used to generate sub-pico-second X-ray pulse and are proposed at ALS at LBNL. A 2-cell structure has been simulated earlier to achieve the required deflecting voltage with damping waveguide to get low impedance. An aluminum cold test model has been made to demonstrate the simulation and the idea for damping LOM with waveguide. Field distribution as well as (R/Q)s are measured using 'bead-pull' method. Qs with/without waveguide loaded are measured and compared with simulation. Detailed configuration and experiment progress is presented.