Neutrino Spectra and Uncertainties for MINOS

The MINOS experiment at Fermilab has released an updated result on muon disappearance based upon 2.5 x 10^20 protons on target. The experiment utilizes the intense source of muon neutrinos provided by the NuMI beam line. This note summarizes the systematic uncertainties in the experiment’s knowledge of the flux and energy spectrum of the neutrinos from NuMI.