Determining the Neutrino Flux from Accelerator Neutrino Beams

Man made sources of neutrinos, from reactors and proton accelerators, are providing the best experimental sensitivities to determining the unknown neutrino oscillation parameters such as θ13, the mass hierarchy, and the CP phase. In addition, these experiments enable the measurements of the known neutrino oscillation parameters with higher precision and the search for new neutrino oscillation phenomena. A critical component of any neutrino oscillation experiment is the precision determination of the neutrino flux from the source, and its composition. I will summarize the different techniques used by current short and long baseline neutrino accelerator experiments to determine the unoscillated neutrino flux, and discuss the implications for future experiments.