Neutrino oscillation is a phenomenon that occurs due to mixing between neutrino mass and flavor eigenstates. These oscillations are described by a mixing matrix, the smallest angle of which, θ13, remained unmeasured until recently, with the development of a new generation of reactor neutrino oscillation experiments, of which Double Chooz is one. The detection of neutrinos in such experiments is assailed by several types of backgrounds, which are caused by muons traversing in or near the detector, and which may degrade the sensitivity of the θ13 measurement. This thesis describes several techniques for vetoing these backgrounds, including hardware systems constructed to efficiently detect muons and veto their resulting events, and targeted software vetoes designed to cut background events. We additionally describe methods to measure the rate and spectrum of the background events remaining after vetoes have been applied. The background-reduced analysis results in a measurement of sin22θ13 = 0.091 +0.029-0.032.
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- Physics, Elementary Particles and High Energy