Underground

Geochemistry—Underground production of neutrons, 39Ar and 21Ne depends on local U, Th, K abundance. Comparing predictions of underground noble gas ’ isotopic composition to newly available measurements can tell us about the source rock U, Th, K content. Dark matter experiments — Argon detectors for WIMP searches require low-radioactivity argon (low 39Ar), and there is ongoing effort driven by the experimental particle physics community to measure 39Ar in underground gas sources at unprecedented sensitivity. Hydrology — The radioactivity of 39Ar (half life 269 years) produced in the atmo-sphere is used inhydrological argon dating. Knowledge of underground 39Ar production rate is necessary for accurate age determination. Curiosity—Existing calculations of nucleogenic 39Ar production disagree and are unclear. Why? Goal Calculate underground nucleogenic production rate of 39Ar. Along the way, neutron and 21Ne production rate are calculated