Harmonic number jump acceleration of muon beams in zero-chromatic FFAG rings

A way to accelerate muon beams rapidly with zero-chromatic fixed field alternating gradient (FFAG) rings is considered in this paper. It is based on the harmonic number jump acceleration and allows the use of constant frequency rf cavities, although the lattice is not isochronous. To overcome the limitations imposed by this acceleration method, a new type of zero-chromatic FFAG lattice, which includes dispersion suppressor insertions, is proposed. Design principles of such a lattice are presented. An example of a 3.6–12.6 GeV muon ring for the simultaneous acceleration of μ + and μ − beams is described. Step-wise particle tracking is used to demonstrate the large 6D acceptance of this scheme.