A Shared Superconducting Linac for Protons and Muons

It has been shown how a superconducting Linac that was designed to be a high-intensity proton driver for Fermilab [1] can be modified and augmented to also serve as the muon accelerating section for a neutrino factory [2]. In this report we consider the same approach, where the Linac does double duty, but with the idea that the Linac and other parameters are chosen to serve only as a neutrino factory. This "greenfield" approach allows the most economical choices for such a neutrino factory and could provide a baseline cost estimate to be compared to other approaches where other methods such as FFAG synchrotrons are used. Recent advances in muon cooling [3] have the promise of muon emittances that are compatible with high frequency superconducting accelerating structures that are by now sufficiently mature for reliable cost estimates. The muon cooling required for such an approach to a muon collider, although there have been impressive theoretical advances and simulation results, remains still to be proved. In this report we discuss the uncertainties in the design parameters that will depend on the muon cooling efforts that are now underway.