| The SciBath detector is an 80 liter liquid scintillator detector read out by a three dimensional grid of 768 wavelength-shifting fibers. Initially conceived as a fine-grained charged particle detector for neutrino studies that could image charged particle tracks in all directions, it is also sensitive to fast neutrons (15-200 MeV). In fall of 2011 the apparatus performed a three month run to measure cosmic-induced muons and neutrons 100 meters underground in the FNAL MINOS near-detector area. Data from this run has been analyzed and resulted in measurements of the cosmic muon flux as 0.80 +/- 0.04 m-2s-1, the cosmogenic fast neutron flux as (1.5 +/- 1.4) x 10-2 m-2 s-1, and the neutron production rate from muon spallation in liquid scintillator as (3.8 +/- 3.2) x 10-4 n/mu (g/cm2)-1. Additionally, the cosmic muon angular distribution and neutron energy distribution have been measured. These results can be extrapolated to future measurements of fast-neutron backgrounds at other underground facilities. This thesis presents a summary of the physics relevant to underground muons and fast neutrons, the SciBath detector, the analysis methodology that was used for the results presented, and comparisons between our results and those of other experiments and simulations. |
