This revision contains suggested improvements by PRSTAB referees. We consider a linear muon beam cooling-channel in which a series of contiguous RF cavities filled with gaseous absorber is imbedded in a helical magnetic field. In this special field, composed of a solenoidal field with superimposed helical transverse dipole and quadrupole fields, higher momentum corresponds to a longer path length and therefore larger ionization energy loss in the dense gaseous hydrogen absorber. This correlation of momentum with energy loss provides the emittance exchange mechanism needed to achieve six-dimensional ionization cooling. In this scheme, the energy loss, the RF energy regeneration, the longitudinal cooling, and the transverse cooling happen simultaneously.
The theory of this helical channel is described to support the analytical prediction of almost a factor of a million reduction in 6D phase space volume in a channel about 56 meters long. Particle beam dynamics equations are derived and beam stability conditions explored. Cooling equations are derived, including expressions for decrements and equilibrium emittances.
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URL http://www-mucool.fnal.gov/mcnotes/public/pdf/muc0284/muc0284.pdf
This is revision # 3
Posted by Rolland Johnson