Simulation of Cosmogenic Background's at Underground Facilities

Fast neutrons produced by cosmic muons in rock surrounding an underground facility can generate irreducible backgrounds in detectors, and in some experiments determine the sensitivity. Understanding the muon-induced production and the response of underground detectors to fast neutrons is crucial for the design of next generation low background experiments. Simulations were conducted using the GEANT4-based Monte Carlo package MaGe, a joint development between the Majorana and Gerda collaborations. Simulations of the total muon-induced neutron background and spectrum as a function of depth, and the response of the proposed Majorana experiment will be presented.