PNNL

Abstract

39Ar and 42Ar produce irreducible backgrounds for several argon-based dark matter and neutrino experiments. The use of low-radioactivity underground argon (UAr) could be a solution to the problem. The DarkSide-50 experiment demonstrated that argon derived from underground sources can contain a much lower concentration of 39Ar than atmospheric argon. Following this success, the Global Argon Dark Matter Collaboration (GADMC) is procuring hundreds of tons of UAr for the DarkSide-20k detector. To serve the broader community need, it is increasingly important to identify new sources of low-radioactivity argon. In addition, understanding the underground production mechanisms of argon radioisotopes and devising methods to measure them at ultra-low levels is necessary. The use of low-radioactivity argon could be crucial to expanding the physics goals and sensitivity of next-generation large-scale argon-based experiments.