  Cosmic muon interactions are important contributors to backgrounds in
underground detectors when searching for rare events. Typically neutrons
dominate this background as they are particularly difficult to shield and
detect in a veto system. Since actual background data is sparse and not well
documented, simulation studies must be used to design shields and predict
background rates. This means that validation of any simulation code is
necessary to assure reliable results. This work studies the validation of the
FLUKA simulation code, and reports the results of a simulation of cosmogenic
background for a liquid argon two-phase detector embedded within a water tank
and liquid scintillator shielding.
