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Yonehara, K.

Paper Title Page
WEPLS007 A Six-dimensional Muon Beam Cooling Experiment 2409
 
  • R.P. Johnson, M. Alsharo'a, M.A.C. Cummings, M. Kuchnir, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois
  • V.S. Kashikhin, V. Yarba, K. Yonehara
    Fermilab, Batavia, Illinois
 
  Ionization cooling, a method for shrinking the size of a particle beam, is an essential technique for the use of muons in future particle accelerators. Muon colliders and neutrino factories, examples of such future accelerators, depend on the development of robust and affordable ionization cooling technologies. A 6D cooling experiment has been proposed, incorporating a novel configuration of helical and solenoidal magnets in a prototype cooling channel. This Helical Cooling Channel (HCC) experiment is being designed with simulations and prototypes to provide an affordable and striking demonstration that 6D muon beam cooling is understood well enough to enable intense neutrino factories and high-luminosity muon colliders. Because of the large amount of expected beam cooling, helium instead of hydrogen can be used for the initial experiment, avoiding the safety complications of hydrogen. Cryostats are currently being developed using internal heat exchangers for simple, effective and safe hydrogen absorber systems to use in later cooling experiments and real cooling channels. The experimental design choices and corresponding numerical simulations are reviewed.  
WEPLS016 Studies of a Gas-filled Helical Muon Beam Cooling Channel 2424
 
  • R.P. Johnson, K. Paul, T.J. Roberts
    Muons, Inc, Batavia
  • Y.S. Derbenev
    Jefferson Lab, Newport News, Virginia
  • K. Yonehara
    Fermilab, Batavia, Illinois
 
  A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. We consider liquid helium and liquid hydrogen absorbers in HCC segments that alternate with RF accelerating sections and we also consider gaseous hydrogen absorber in pressurized RF cavities imbedded in HCC segments. In the case of liquid absorber, the possibility of using superconducting RF in low magnetic field regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates. Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.  
TUPCH147 High Pressure RF Cavities in Magnetic Fields 1364
 
  • P.M. Hanlet, M. Alsharo'a, R. E. Hartline, R.P. Johnson, M. Kuchnir, K. Paul
    Muons, Inc, Batavia
  • C.M. Ankenbrandt, A. Moretti, M. Popovic
    Fermilab, Batavia, Illinois
  • D.M. Kaplan, K. Yonehara
    Illinois Institute of Technology, Chicago, Illinois
 
  A study of RF breakdown in pressurized cavities immersed in strong magnetic fields has begun as part of a program to develop RF cavities filled with dense hydrogen gas to be used for muon ionization cooling. A pressurized 805 MHz test cell is being used at Fermilab to compare the conditioning and breakdown behavior of copper, molybdenum, and beryllium electrodes as functions of hydrogen and helium gas densities and magnetic field strength. These results will be compared to the predicted or known RF breakdown behavior of these metals in vacuum with and without external magnetic fields.