Author: Mitchell, C.E.
Paper Title Page
MOPWO062 A Parallel Multi-objective Differential Evolution Algorithm for Photoinjector Beam Dynamics Optimization 1031
  • J. Qiang, C.E. Mitchell, S. Paret, R.D. Ryne
    LBNL, Berkeley, California, USA
  • Y.X. Chao
    UCB, Berkeley, California, USA
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
In photoinjector design, there is growing interest in using multi-objective beam dynamics optimization to minimize the final transverse emittances and to maximize the final peak current of the beam. Most previous studies in this area were based on genetic algorithms. Recent progress in optimization suggests that the differential evolution algorithm could perform better in comparison to the genetic algorithm. In this paper, we propose a new parallel multi-objective optimizer based on the differential evolution algorithm for photoinjector beam dynamics optimization. We will discuss the numerical algorithm and some benchmark examples. This algorithm has the potential to significantly reduce the computation time required to reach the optimal Pareto solution.
TUPME062 Simulation and Analysis of Microbunching Instability in a High Repetition rate FEL Beam Delivery System 1709
  • J. Qiang, J.N. Corlett, P. Emma, C.E. Mitchell, M. Venturini
    LBNL, Berkeley, California, USA
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
Microbunching instability in the accelerator beam delivery system of an FEL can significantly degrade the electron beam quality and limit performance of the X-ray radiation. In this paper, we present detailed numerical simulation and analytical analysis of the microbunching instability in a high repetition rate X-ray FEL beam delivery system that is being studied at Lawrence Berkeley National Laboratory. Our results suggest that by using a flexible accelerator design and a laser heater, the effects of microbunching instability can be suppressed without significantly sacrificing the final electron beam quality.
TUPWA057 Effects of Transient CSR Wakefields on Microbunching in a Bunch Compressor 1832
  • C.E. Mitchell, J. Qiang
    LBNL, Berkeley, California, USA
  Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The standard analytical model of CSR-induced microbunching in a bunch compressor chicane makes use of a steady-state 1-D model of the longitudinal CSR interaction. This model is numerically generalized to include the effects of transient CSR wakefields due to bend entry and exit, as well as CSR that is generated in upstream bends and propagates across one or more lattice elements before interacting with the beam. The resulting linear integral equation for CSR-induced microbunching is solved numerically for the second bunch compressor of a proposed Next Generation Light Source.