Muon Acceleration in a Superconducting Proton Linac

This note describes how a future Fermilab proton driver [1] based on TESLA superconducting linac modules can perform as both the source of protons to produce the muons and as the accelerator of the muons to be used for a neutrino factory or muon collider. Recent advances in muon cooling [2] have the promise of muon emittances that are compatible with the 1300 MHz accelerating structures that are the basis for the ILC design. In the design described here, H ions are accelerated to 8 GeV in the superconducting Linac, then stripped, stored and bunched in a ring while the Linac cavities are rephased for muon accleleration. Then the protons are extracted from the ring to produce pions and muons which are cooled in a few hundred meters, accelerated to a few GeV and injected into the Linac at the 1 β = point for acceleration to add 7 GeV. By recirculating the muons in the constant frequency section of such a proton driver Linac, even higher energies can be achieved quickly so that losses from muon decay are minimized. By adding additional refrigeration and RF power, the repetition rate of the Linac can be increased to make large increases in the average flux of a neutrino factory and the average luminosity of a muon collider.