Monte Carlo simulation of neutrino production by medium-energy protons in a beam stop

Abstract We describe a Monte Carlo program that generates the distribution of stopped pions produced by medium-energy protons in a beam stop. This distribution can be used to predict the absolute neutrino flux from this source to 7.3%. The same Monte Carlo program also calculates neutrino fluxes from the in-flight decay of pions and muons in the beam stop environment.