Speaker
Description
39Ar and 42Ar are 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 be highly depleted of 39Ar. Following this success, the Global Argon Dark Matter Collaboration (GADMC) is procuring hundreds of tons of UAr for the DarkSide-20k detector. However, there is a broader community need, making 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.
In this talk, I will discuss how the use of low-radioactivity argon could be crucial to expanding the physics goals and sensitivity of next-generation large-scale argon-based experiments. The underground production mechanisms of 39Ar and 42Ar will be discussed. 42Ar/42K decay backgrounds and an estimate of 42Ar production in the continental crust will be presented in some detail. Finally, the prospects of a kilo-ton scale UAr experiment will be discussed.
