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Todd, D.S.

Paper Title Page
TPPE010 A Parallel 3D Model for the Multi-Species Low Energy Beam Transport System of the RIA Prototype ECR Ion Source VENUS 1183
 
  • J. Qiang, D. Leitner, D.S. Todd
    LBNL, Berkeley, California
 
  Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. DOE under Contract DE AC03-76SF00098.

The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and optimize the low energy beam line optics of the RIA front end, we have developed a new parallel three-dimensional model to simulate the low energy, multi-species beam transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multi-section overlapped computational domain has been used to break the original transport system into a number of independent subsystems. Within each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented.

 
TPPE032 Particle-in-Cell Simulations of the VENUS Ion Beam Transport System 2236
 
  • D.S. Todd, D. Leitner, C.M. Lyneis, J. Qiang
    LBNL, Berkeley, California
  • D.P. Grote
    LLNL, Livermore, California
 
  Funding: This work was supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. DOE under Contract DE AC03-76SF00098

The next-generation superconducting ECR ion source VENUS serves as the prototype injector ion source for the linac driver of the proposed Rare Isotope Accelerator (RIA). The high-intensity heavy ion beams required by the RIA driver linac present significant challenges for the design and simulation of an ECR extraction and low energy ion beam transport system. Extraction and beam formation take place in a strong (up to 3T) axial magnetic field, which leads to significantly different focusing properties for the different ion masses and charge states of the extracted beam. Typically, beam simulations must take into account the contributions of up to 30 different charge states and ion masses. Two three-dimensional, particle-in-cell codes developed for other purposes, IMPACT and WARP, have been adapted in order to model intense, multi-species DC beams. A discussion of the differences of these codes and the advantages of each in the simulation of the low energy beam transport system of an ECR ion source is given. Direct comparisons of results from these two codes as well as with experimental results from VENUS are presented.