Low Energy Stages - 'Dogbone' Muon RLA

A conceptual design of lower energy stages of muon accelerator is presented. The scheme is based on two superconducting, 200 MHz linacs: a single pass linear pre-accelerator followed by a multi-pass 'dogbone' recirculating linac (RLA). In the presented scenario, acceleration starts after ionization cooling at 273 MeV/c and proceeds to 5 GeV, where the beam is injected into a complex of FFAG rings for further acceleration. The key conceptual issues are addressed and implemented in the overall acceleration scheme: capture, acceleration, transport and preservation of large phase space of fast decaying species. Beam transport of large-momentum-spread beams is facilitated through appropriate lattice design choices. The proposed linear optics for 'droplet' return arcs optics is further supplem ented with a sextupole correction to suppress chrom atic effects contributing to the horizontal emittance dilution.