Yonehara, K.

Paper	Title	Page
TU203	High Pressure, High Gradient RF Cavities for Muon Beam Cooling	266
	R. P. Johnson, M. Popovic FNAL, Batavia, Illinois M.M. Alsharo'a, R.E. Hartline, M. Kuchnir, T.J. Roberts Muons, Inc., Batavia C. M. Ankenbrandt, A. Moretti Fermilab, Batavia, Illinois K. Beard, A. Bogacz, Y.S. Derbenev Jefferson Lab, Newport News, Virginia D. M. Kaplan, K. Yonehara IIT, Chicago, Illinois
	High intensity, low emittance muon beams are needed for new applications such as muon colliders and neutrino factories based on muon storage rings. Ionization cooling, where muon energy is lost in a low-Z absorber and only the longitudinal component is regenerated using RF cavities, is presently the only known cooling technique that is fast enough to be effective in the short muon lifetime. RF cavities filled with high-pressure hydrogen gas bring two advantages to the ionization technique: the energy absorption and energy regeneration happen simultaneously rather than sequentially, and higher RF gradients and better cavity breakdown behavior are possible than in vacuum due to the Paschen effect. These advantages and some disadvantages and risks will be discussed along with a description of the present and desired RF R&D efforts needed to make accelerators and colliders based on muon beams less futuristic.
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