Simulating external γ-ray calibration sources for nEXO

nEXO is an international collaboration focused on detection of neutrinoless double-beta decay (0νββ), a rare lepton number violating decay event that, if observed, would provide insight into the nature of the neutrino. The nEXO detector is a 5 tonne liquid xenon time projection chamber, enriched in xenon-136, based on ultra-low background liquid xenon technology validated by the EXO-200 experiment. The goal for the planned nEXO detector is to be sensitive to Xe-136 0νββ events with a half-life on the order of 10²⁸ years. To obtain this sensitivity it is essential to understand the detector response to different calibration sources. My research simulates the external γ-ray sources cobalt-60 and cesium-137 at a number of different positions around the detector to improve understanding of calibration techniques and detector behavior.