A large magnetic detector for the neutrino factory

The physics opportunities of the neutrino factory have been the subject of a number of recent studies. It was shown that sensitive measurements of the angle 0(13), of MSW effects, and of the sign of the atmospheric mass difference Delta m(23)(2) are possible, and even CP violation in the neutrino mixing matrix may be within reach. The focus of interest is the oscillation nu(e) --> nu(mu), which leads in the well-defined neutrino beam of the neutrino factory to 'wrong-sign' muon events. In this paper, we show that a large magnetic detector will be capable of detecting with high efficiency and small backgrounds such wrong-sign muon events. We present a conceptual design of the apparatus and its performance. Various backgrounds are analysed and we demonstrate that they can be sufficiently suppressed by appropriate cuts. We illustrate the performance of the large magnetic detector by its sensitivity to the angle theta(13). (C) 2000 Published by Elsevier Science B.V. All rights reserved.