The nEXO Radioactivity and Background Control Program

nEXO is a proposed next-generation experiment to search for the neutrinoless double beta decay of ¹³⁶Xe. The experiment is designed around a large time projection chamber, envisaged to contain 5000 kg of isotopically enriched xenon in order to achieve a half-life sensitivity of 1.35·10²⁸ years. To reach such sensitivity requires a stringent radioactive background control and careful material selection effort.

In this talk I will present the nEXO background budget, explain material selection criteria, demonstrate analytical and computational tools used for background control, and discuss major background sources.