Author: Huang, C.-K.
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MOPLH22 Focusing Studies of an Electron Beam in Diamond Field Emitter Array Cathodes 217
  • R.L. Fleming, H.L. Andrews, D. Gorelov, C.-K. Huang, D. Kim, J.W. Lewellen, K.E. Nichols, V.N. Pavlenko, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  Funding: Los Alamos National Laboratory LDRD Program
We present the simulations and test results for focusing studies performed on diamond field emitter array cathodes. This design utilized a simple variable-focus solenoidal lens in conjunction with a scanning wire technique in order to measure the beam spot size. The spot size was measured by scanning a thin copper wire across the beam in 1 µm increments, with voltage being measured and averaged at each location in order to map the location and intensity of the beam. Scans were taken at different distances away from the magnetic center of the lens, and show good agreement with our simulations of the beam. Ultimately this has allowed us to focus the beam to a spot size of 5.72 µm with an average current of 15.78 µA.
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About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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Comparison of Numerical Methods for the Calculation of Synchrotron Radiation From Electrons  
  • F.Y. Li, B.E. Carlsten, R. Garimella, C.-K. Huang, T.J. Kwan
    LANL, Los Alamos, New Mexico, USA
  The phenomenon of synchrotron radiation from electrons is at the core of modern accelerator based light sources. While synchrotron radiation in the far field has been well established, the self-consistent beam dynamics due to the near-field synchrotron radiation becomes increasingly important as high-brightness beams and coherent light sources are developed. Since it is difficult to diagnose the near fields in experiments, accurate and efficient numerical methods are essential to the design of these light sources. Here, we investigate several existing methods for the calculation of the radiation near fields, including the finite difference method, the Lienard-Wiechert method and a novel near-field method. We compare the accuracy and efficiency of these methods in both 1D and multi-dimensions, for both steady-state and dynamic beam trajectories, both radiation field and space charge field, as well as for both coherent and incoherent fields. We also discuss a self-similarity feature in the synchrotron radiation that can be exploited to improve the calculation.
Work supported by the LDRD program at LANL.
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