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Beard, K.

Paper Title Page
TPPP013 Simulations of Parametric Resonance Ionization Cooling of Muon Beams 1321
 
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • R.P. Johnson, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
 
  Funding: This work was supported in part by DOE SBIR grants DE-FG02-03ER83722, and 04ER84016.

The technique of using a parametric resonance to allow better ionization cooling is being developed to create small beams so that high collider luminosity can be achieved with fewer muons. In the linear channel that is studied in this effort, a half integer resonance is induced such that the normal elliptical motion of particles in x-x' phase space becomes hyperbolic, with particles moving to smaller x and larger x' as they pass down the channel. Thin absorbers placed at the focal points of the channel then cool the angular divergence of the beam by the usual ionization cooling mechanism where each absorber is followed by RF cavities. Thus the phase space of the beam is compressed in transverse position by the dynamics of the resonance and its angular divergence is compressed by the ionization cooling mechanism. We report the first results of simulations of this process, including comparisons to theoretical cooling rates and studies of sensitivity to variations in absorber thickness and initial beam conditions.

 
TPPP052 Simulations of a Gas-Filled Helical Muon Beam Cooling Channel 3215
 
  • K. Yonehara, D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • R.P. Johnson, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
 
  Funding: This work was supported in part by DOE STTR/SBIR grants DE-FG02-02ER86145 and 03ER83722.

A helical cooling channel (HCC) has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of a series of RF cavities filled with dense hydrogen gas that acts as the energy absorber for ionization cooling and suppresses RF breakdown in the cavities. Magnetic solenoidal, helical dipole, and helical quadrupole coils outside of the RF cavities provide the focusing and dispersion needed for the emittance exchange for the beam as it follows a helical equilibrium orbit down the HCC. In the work presented here, two Monte Carlo programs have been developed to simulate a HCC to compare with the analytic predictions and to begin the process of optimizing practical designs that could be built in the near future. We discuss the programs, the comparisons with the analytical theory, and the prospects for a HCC design with the capability to reduce the six-dimensional phase space emittance of a muon beam by a factor of over five orders of magnitude in a linear channel less than 100 meters long.

 
ROAA005 Recent Innovations in Muon Beam Cooling and Prospects for Muon Colliders 419
 
  • R.P. Johnson, M. Alsharo'a, P.M. Hanlet, R. E. Hartline, M. Kuchnir, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • C.M. Ankenbrandt, E. Barzi, L. DelFrate, I.G. Gonin, A. Moretti, D.V. Neuffer, M. Popovic, G. Romanov, D. Turrioni, V. Yarba
    Fermilab, Batavia, Illinois
  • K. Beard, S.A. Bogacz, Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • D.M. Kaplan, K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
 
  Funding: This work was supported in part by DOE SBIR/STTR grants DE-FG02-02ER86145, 03ER83722, 04ER84015, 04ER86191, and 04ER84016.

A six-dimensional(6D)cooling channel based on helical magnets surrounding RF cavities filled with dense hydrogen gas* is used to achieve the small transverse emittances demanded by a high-luminosity muon collider. This helical cooling channel**(HCC) has solenoidal, helical dipole, and helical quadrupole magnetic fields to generate emittance exchange. Simulations verify the analytic predictions and have shown a 6D emittance reduction of over 3 orders of magnitude in a 100 m HCC segment. Using three such sequential HCC segments, where the RF frequencies are increased and transverse dimensions reduced as the beams become cooler, implies a 6D emittance reduction of almost six orders of magnitude. After this, two new post-cooling ideas can be employed to reduce transverse emittances to one or two mm-mr, which allows high luminosity with fewer muons than previously imagined. In this report we discuss the status of and the plans for the HCC simulation and engineering efforts. We also describe the new post-cooling ideas and comment on the prospects for a Higgs factory or energy frontier muon collider using existing laboratory infrastructure.

*R. P. Johnson et al. LINAC2004, www.muonsinc.com/TU203.pdf. **Y. Derbenev and R.P. Johnson, Submitted to PRSTAB, http://www-mucool.fnal.gov/mcnotes/public/pdf/muc0284/muc0284.pdf.