Author: Li, W.W.
Paper Title Page
THPMK018 Design of a rotationally symmetric S-band photocathode RF gun 4336
 
  • Zh. X. Tang
    USTC, Hefei, Anhui, People's Republic of China
  • Z.G. He, W.W. Li, Y.J. Pei, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  The photocathode RF gun is one of the most critical components for high quality electron beam sources. The asymmetric multi-pole field contributes to the transverse emittance growth and degrades the beam quality. In order to overcome the problem, we propose a novel rotationally symmetric 1.6 cell RF gun to construct the symmetric field in this paper. The concrete proposal is that a coaxial cell with a symmetrical distribution of four grooves is concatenated to the first 0.6 cell at the photocathode end to form a new resonant cell (NRC) to mantain the symmetric multi-pole field in 1.6 cell. Our simulations indicate that 3D multi-pole fields of NRC are with the perfect symmetry. After that, the profile of the RF gun is optimized to improve the shunt impedance and mode separation and make the surface peak electric field at the photocathode end. Our simulations demonstrate promising outlook of using coaxial cell for photocathode RF guns with various applications.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK018  
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THPMK124 The Radiation Source for a Pre-Bunched THz Free Electron Laser 4608
 
  • R. Huang, Z.G. He, Q.K. Jia, H.T. Li, W.W. Li, Y. Lu, L. Wang, Z. Zhao
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: Work is supported by National Natural Science Foundation of China (Grant No. 51627901)
Electron beam, generated in a photoinjector and bunched at terahertz (THz) frequency, will excite the coherent THz radiation when entering an undulator. We present a scheme of the radiation source for the pre-bunched THz free electron laser (FEL). The physical design of electron source is described in detail. The radiation frequency is widely tunable by both the pulse train tuning and the undulator gap tuning. It is simulation proved that the radiation power is greatly enhanced in our scheme. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK124  
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THPMK126 Numerical Method for Longitudinal Dynamics of a Terahertz Cherenkov Free Electron Laser Driven by a Mev Picosecond Electron Beam 4614
 
  • W.W. Li, Z.G. He, Q.K. Jia, S.M. Jiang, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • D. He
    Anhui Electrical Engineering Professional Technique College, Hefei, People's Republic of China
  
  Funding: Natural Science Foundation of China (11705198, 11775216) China Postdoctoral Science Foundation (2017M622023) Fundamental Research Funds for the Central Universities (WK2310000061)
Corrugated or dielectric structures have been widely used for producing electron bunch train or THz radiation source. Recently, a novel scheme of sub-terahertz free electron laser (FEL) from a metallic pipe with corrugated walls driven by a non-ultra-relativistic (<10 MeV) picosecond electron beam was proposed and analyzed using the Vlasov-Maxwell equations. In this paper, we use the dielectric loaded waveguide instead, and a numerical method for the longitudinal beam dynamics and electromagnetics of the FEL interaction is presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK126  
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