Keyword: space-charge
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PO13 Longitudinal Beam Motion in the KEK Digital Accelerator: Tracking Simulation and Experimental Results simulation, induction, acceleration, synchrotron 83
 
  • X. Liu
    Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
  • T. Adachi
    Sokendai, Ibaraki, Japan
  • S. Harada
    Tokyo City University, Tokyo, Japan
  • T. Iwashita
    KEK, Ibaraki, Japan
  • K. Takayama, T. Yoshimoto
    TIT, Yokohama, Japan
  
  Beam commissioning in the KEK Digital Accelerator*, which is a small scale induction synchrotron (IS), has been conducted since the middle of 2011. Longitudinal beam motion in the induction synchrotron, which utilizes induction cells (IC) for acceleration and confinement, is characterized as barrier bucket acceleration. . These ICs are driven by the switching power supply (SPS). Pulse voltage is fully managed by the gate control for solid-state switching elements in the SPS, where FPGAs and DSPs take a key role**. A tracking code has been developed to understand the longitudinal motion affected by longitudinal space charge forces, under programmed settings of confinement and acceleration voltage. This code, where the trigger control scenario is fully implemented, calculates temporal evolution of momentum and phase of macro-particles. The simulation result has well reproduced beam commissioning results, such as bunch squeezing experiment and barrier bucket acceleration. In addition, the code is going to be applied to explain the rapid growth of micro-bunch structure in the injected ion bunch.
* T. Iwashita et al., “KEK Digital Accelerator” , Phys. Rev. ST-AB 14, 071301 (2011). And K.Takayama et al., in this conference.
** S.Harada, Ms. Thesis (TCU) (2011).
 		 
 
PO17 Simulation of Electron and Ion Dynamics in an EBIS ion, electron, simulation, background 97
 
  • L. Zhao, E.G. Evstati, J.S. Kim
    Far-Tech, Inc., San Diego, California, USA
  • E.N. Beebe, A.I. Pikin
    BNL, Upton, Long Island, New York, USA
  
  Funding: Grant supported by DOE office of Nuclear Physics
To model the dynamics of the ions in an Electron Beam Ion Source (EBIS), a time-dependent, self-consist particle-in-cell Monte Carlo code (EBIS-PIC) has been developed by FAR-TECH, Inc. The energetic background electron beam is modeled by PBGUNS (http://www.far-tech.com/pbguns/index.html) by dividing the long beam path into several segments to resolve the big length-to-radius spatial scaling problem. The injected primary ions and ionized neutral gas ions are tracked using Monte Carlo method which includes the ionization, charge-exchange and Coulomb collisions with the electron beam and the neutral gas in the potential well, which is calculated by solving the Poisson equation each time step. EBIS-PIC has been able to predict the spatial and velocity space distributions and the evolution of the charge state distribution (CSD) of trapped ions in EBIS devices operating in fast or slow trapping mode. The physical model of EBIS-PIC code and the simulations of the trapping and charge-breeding of injected Cs+1 ions on the Test EBIS* at BNL will be presented. The simulation results have shown good consistency with the experiments.
* S. Kondrashev, J.G. Alessi, E.N.Beebe, C. Dickerson, P.N.Ostroumov, A. Pikin, G. Savard, NIMPR. A, 642 (2011), 18-24.