Tracking and Mitigating Radon Backgrounds in nEXO

The next Enriched Xenon Observatory (nEXO) experiment plans to search for neutrinoless double beta decay (0nbb) of Xe-136. These 0nbb events are characterized by two beta particles with a total energy of Qbb = 2458 keV. As these events are extremely rare, with a current half-life limit of >3.8 × 10^26 yr from KamLAND-Zen, understanding and mitigating backgrounds near the Qbb energy is essential. By using a liquid xenon time projection chamber and careful material selection, nEXO is able to achieve extremely low background rates and has a projected half-life sensitivity of 1.35 × 10^28 years. The small residual background is dominated by the radon decay-chain progeny, Bi-214 (1.5% 2448 keV gamma decay branch). These events can frequently be tagged as background due to a preceding alpha decay and coincident beta decay. However, this tagging efficiency is strongly dependent on the location of the Bi-214 within the detector. In this talk, I will discuss progress on tracking the radon decay progeny and methods to improve the tagging of the Bi-214 decay background.