Cosmogenic production of Ar37 in the context of the LUX-ZEPLIN experiment

Le résumé fourni par la source

We estimate the amount of $^{37}\mathrm{Ar}$ produced in natural xenon via cosmic-ray-induced spallation, an inevitable consequence of the transportation and storage of xenon on the Earth's surface. We then calculate the resulting $^{37}\mathrm{Ar}$ concentration in a 10-tonne payload (similar to that of the LUX-ZEPLIN experiment) assuming a representative schedule of xenon purification, storage, and delivery to the underground facility. Using the spallation model by Silberberg and Tsao, the sea-level production rate of $^{37}\mathrm{Ar}$ in natural xenon is estimated to be $0.024\text{ }\text{ }\mathrm{atoms}/\mathrm{kg}/\mathrm{day}$. Assuming the xenon is successively purified to remove radioactive contaminants in 1-tonne batches at a rate of $1\text{ }\text{ }\mathrm{tonne}/\mathrm{month}$, the average $^{37}\mathrm{Ar}$ activity after 10 tons are purified and transported underground is $0.058\ensuremath{-}0.090\text{ }\text{ }\ensuremath{\mu}\mathrm{Bq}/\mathrm{kg}$, depending on the degree of argon removal during above-ground purification. Such cosmogenic $^{37}\mathrm{Ar}$ will appear as a noticeable background in the early science data, while decaying with a 35-day half-life. This newly noticed production mechanism of $^{37}\mathrm{Ar}$ should be considered when planning for future liquid-xenon-based experiments.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.