3.1.1 Overview

Introduction 3.1.1 Overview The role of the target system at a Neutrino Factory is to generate a maximal number of pions with an intense proton beam and then capture and guide them into a channel where the decay muons can be bunched, cooled, accelerated and stored in a ring from which the neutrinos emanate upon decay of the muons. In this Study, the proton beam energy is 24 GeV, and the baseline beam power is 1 MW, upgradable to 4 MW. The spectrum of pions from GeV protons interacting with a target peaks at a total momentum near 250 MeV/c, as shown in Fig. 3.1 [1], and has an average transverse momentum #p # # = 150 MeV/c. Thus, the majority of pions are produced at relatively large angles to the proton beam, and are not e#ciently captured by devices placed downstream of the target. For maximal e#ciency, the pion capture system must surround the target. The capture mechanism considered here is a solenoidal magnetic field channel starting at 20 T near the target, then falling ad