Author: Shin, Y.-M.
Paper Title Page
TUPME060 Simulation Analysis on Micro-Bunched Density Modulation from a Slit-Masked Chicane 1509
 
  • Y.-M. Shin, P. Piot, C.R. Prokop
    Northern Illinois University, DeKalb, Illinois, USA
  • D.R. Broemmelsiek, E.R. Harms, A.H. Lumpkin, J. Ruan, J.C.T. Thangaraj
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Pre-bunching a beam at a resonance condition with an accelerating structure vastly improves performance of beam-driven accelerators and undulators since it enhances a beam-wave coupling. We plan to test a slit-mask micro-buncher at the chicane of Fermilab-ASTA 50 MeV beamline in the effort of advanced accelerator research. With the chicane design parameters (bending angle (alpha) of 18 degree, R56 ~ - 0.18 m, and bending radius of ~ 0.78 m), analytic model showed that a slit-mask with W (period) = 900 um and a (aperture width) = 300 um (30 % transparency) generates 100 um spaced micro-bunches with 5 ~ 6 % correlated energy spread. Two kinds of combined beamline simulation, CST-PS+Impact-Z and Elegant+Shower, including space charge and CSR effects, showed that a 900 um spaced, 300 um wide slits placed in the middle of chicane splits 20 pC – 1 nC bunches into ~ 100 um spaced micro-bunches. It is possible that a further optimization of mask design creates sub-100 fs micro-bunches, which is currently under development.
*[1] NIM A 375, 597 (1996)
[2] PRL 101, 054801 (2008)
[3] Y.-E Sun, P. R. G. Piot, FEMILAB-CONF-08-408-APC
** ASTA: Advanced Superconducting Test Accelerator
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME060  
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TUPME061 Ultra-High Gradient Beam-Driven Channeling Acceleration in Hollow Crystalline Media 1512
 
  • Y.-M. Shin, T. Xu
    Northern Illinois University, Dekalb, Illinois, USA
  • G. Flanagan
    Muons, Inc, Illinois, USA
  • E.R. Harms, J. Ruan, V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
  
  Since the recent discovery of the Higgs boson particle, there is an increasing demand in Energy Frontier to develop new technology for a TeV/m range of acceleration gradient. The density of charge carriers, ~ 1024 – 1029 m-3, of crystals is significantly higher than that of a plasma gas, and correspondingly in principle wakefield gradients of up to 0.1 - 10 TV/m are possible. Our simulations (VORPAL and CST-PIC) with Fermilab-ASTA* beam parameters showed that micro-bunched beam gains energy up to ~ 70 MeV along the 100 um long channel under the resonant coupling condition of the plasma wavelength, ~ 10 um. Also, with lowering a charge, electron bunches channeling through a high-density plasma medium have higher energy gain in a hollow channel than in a uniformly filled cylinder, which might be attribute to lower scattering ratios of the tunnel structure. The numerical analysis implied that synthetic crystalline plasma media (e.g. carbon nanotubes) have potential to mitigate constraint of bunch charges required for beam-driven acceleration in high density plasma media. The channeling acceleration** will be tested at the ASTA facility, once fully commissioned.
* ASTA: Advanced Superconducting Test Accelerator
** [1] T. Tajima and M. Cavenago, PRL 59, 13(1987)
[2] P. Chen and R. Noble, SLAC-PUB-7402(1998)
[3] V.Shiltsev, Physics Uspekhi 55, 965(2012)
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME061  
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