Design and simulation of muon ionization cooling channels for the FermilabNeutrino Factory feasibility study

In the past few years, the concept of a high intensity muon storage ring ha s been pursued as an option for the next generation neutrino source. To pro duce the high intensity muon beam needed for the successful operation of a neutrino source, on the order of 10(20) muon decays per year, the phase spa ce occupied by the muon beam must be significantly reduced before the beam is accelerated. The initial transverse emittance of the muon beam before ac celeration is assumed to be 9 pi mm rad. Because of the time limitation imp osed by the muon lifetime, the technique employed to accomplish the desired emittance reduction is ionization cooling. In this paper we present two io nization cooling lattice designs, which use solenoidal focusing elements an d liquid hydrogen absorbers to reduce the muon beam phase space. We discuss the design concepts and engineering constraints for these lattices and pre sent simulation results obtained using a detailed tracing code with a compl ete model of muon-matter interactions. The reduction in transverse emittanc e is approximately a factor of 5. This result is within a factor of 2 of th e total cooling requirements for a successful neutrino factory design and w ithin a factor of 1.4 of the requirements for the main cooling section spec ified in the conceptual design of this machine.