Beam monitoring and near detector requirements for a Neutrino factory or long-baseline beams

Neutrino Factory is a facility for future precision studies of neutrino oscillations. A so called near detector is essential for reaching the aimed precision of neutrino oscillation analysis. Main task of the near detector is to measure the flux of the neutrino beam. Such brilliant neutrino source like Neutrino Factory provides also opportunity for precision studies of various neutrino interaction processes in the near detector. We discuss design concepts of such a detector. Results of simulations of a high resolution scintillating fiber tracker show that it is capable to measure the neutrino flux through pure leptonic interactions with an uncertainty of less than 1%. A full set-up of the near detector consisting of high granularity vertex detector, high resolution tracker and muon catcher is also presented.