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Kim, K.-J.

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TUYAB01 Transverse-transverse and Transverse-longitudinal Phase Space Converters for Tailoring Beam Phase Spaces 775
  • K.-J. Kim
    ANL, Argonne, Illinois
  This talk covers basic beam dynamics theory, including emittance converters and the flat beam technique, and also new ideas for transverse-longitudinal coupling. The work done in collaboration with SLAC, FNAL, and NIU, including a preliminary experiment performed at Fermilab, is to be presented.  
slides icon Slides  
THPMN090 Systematic Study of Undulator Based ILC Positron Source: Production and Capture 2918
  • W. Liu, W. Gai, K.-J. Kim
    ANL, Argonne, Illinois
  A systematic study of the positron production and capture systems for the undulator-based ILC positron source has been performed. Various undulator parameters, such as k and λ, were considered. Our model starts from the electron beam production of the polarized photons in the undulator section, photon transport and collimation in the drift section, and photon interaction on the target (titanium or tungsten). Next, our model transports the produced polarized positrons from the target, through the tapered capturing magnet, and through the normal conducting linac to several hundred MeV. Finally, the captured positrons meeting the damping ring emittance and energy spread requirements are accelerated up to 5 GeV using the standard ILC superconducting cavities. We will present parametric studies for the different scenarios (e.g. 60% polarization vs. unpolarized; target immersed in magnetic field vs. non-immersed) currently under consideration and report on the capturing yield and polarizations achieved for each.  
THPAN090 Fourier Spectral Simulation for Wake Field in Conducting Cavities 3432
  • M. Min, Y.-C. Chae, P. F. Fischer, K.-J. Kim
    ANL, Argonne, Illinois
  • Y. H. Chin
    KEK, Ibaraki
  Recent demand of short-bunch beams poses high-order computational tools for investigating beam dynamics in order to improve the beam quality. We have studied a new computational approach with spectrally accurate high-order approximation for wake field calculations. The technique employs the standard Fourier basis combined with a post-processing procedure for noise reduction by Gegenbauer reconstruction. We integrate this scheme into the existing 2D wake field calculation code ABCI and investigate possible enhancemance of its performance on the same grid base. We will demontrate 2D wake potential simulations for various cylindrically symmetric structures with the quality improvement in comparison to the conventional lower-order method.  
THPAN094 Design Study of a Transverse-to-Longitudinal Emittance Exchange Proof-of-principle Experiment 3441
  • Y.-E. S. Sun, K.-J. Kim, J. G. Power
    ANL, Argonne, Illinois
  • P. Piot, M. M. Rihaoui
    Northern Illinois University, DeKalb, Illinois
  Funding: Dr. Sun's work is supported by U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Transverse-to-longitudinal emittance exchange can be achieved through certain arrangements of dipole magnets and dipole mode rf cavity. Theory on such schemes has been developed in the past several years. In this paper we report our numerical simulations on the emittance exchange using particle tracking codes. Photoelectron beams with energy less than 20 MeV are used, as our purpose of simulations is to study the feasibility of performing such emittance exchange at existing facilities of beam energy at this level. Parametric studies of the dipole magnets and cavity strengths, as well as initial beam parameters, are presented.

THPAS094 Transverse to Longitudinal Emittance Exchange Beamline at the A0 Photoinjector 3702
  • R. P. Fliller
    BNL, Upton, Long Island, New York
  • D. A. Edwards, H. Edwards
    Fermilab, Batavia, Illinois
  • K. C. Harkay, K.-J. Kim
    ANL, Argonne, Illinois
  • T. W. Koeth
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  Funding: Work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

The A0 photoinjector is being reconfigured to test the principal of transverse to longitudinal emittance exchange as proposed by Emma et. al., Kim and Sessler, and others. The ability to perform such an exchange could have major advantages to FELs by reducing the transverse emittance. Several schemes to carry out the exchange are possible and will be reported separately. At the Fermilab A0 Photoinjector we are constructing a beamline to demonstrate this transverse to longitudinal emittance exchange. This beamline will consist of a dogleg, and a TM110 5 cell copper cavity followed by another dogleg. The beamline is designed to reuse the bunch compressor dipoles of the photoinjector, along with some existing diagnostics. Beamline layout and optics discussed along with inital data. Future possibilites of performing a similar experiment at the proposed NML facility at Fermilab are also discussed.