Lawrence Berkeley National Laboratory

To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO site and operated during the final 3 months of the experiment. From these measurements, an upper limit of 0.0021 counts/(keV.kg.yr) (95percent c.l.) was obtained on the cosmic ray induced background in the neutrinoless double beta decay region of interest. The measurements were also compared to Geant4 simulations.