Validation of Argon from Underground Sources for Use in the DarkSide-50 Detector

Liquid argon is an attractive target for dark matter searches due to its low cost and exemplary event discrimination. However, atmospherically derived argon contains the beta-emitter 39Ar which confounds the growth of dual-phase time projection chamber (TPC) style detectors to the ton-scale. The DarkSide Collaboration seeks to bypass this limitation by extracting argon from deep underground, from a location known to contain significantly less 39Ar than atmospherically derived argon. This thesis will summarize the e orts taken to produce the first batch of underground argon, focusing on the first operation of the underground argon in a dual-phase TPC to validate the purity of the product, performed at Fermilab using the SCENE cryostat