Kavli Affiliate: Moritz Guenther
| First 5 Authors: Mario Schwarz, Mario Schwarz, , ,

| Summary:
Atmosphere-sourced argon contains traces of $^42$Ar, whose $β^-$-decaying progeny $^42$K represents a significant intrinsic background for rare-event experiments using liquid argon (LAr) as detector or shielding medium. Understanding and mitigating this background is crucial for current and future large-scale detectors in neutrino and dark-matter physics. To enable controlled studies of $^42$K behavior and suppression techniques, $^42$Ar was produced by irradiating natural argon with 34 MeV $^7$Li$^3+$ ions at the Maier-Leibnitz-Laboratorium tandem accelerator, using beam currents of $101 pm 5$ nA and $140 pm 5$ nA, yielding $476 pm 9$ Bq within two weeks, corresponding to a production rate of $sim 1 times 10^6$ atoms$,$s$^-1$. The activated argon was injected into the one-ton SCARF cryostat, where two HPGe detectors monitored the subsequent $^42$K activity build-up. A time-dependent model describing $^42$Ar mixing and $^42$K equilibration in LAr yielded characteristic mixing time constants between one and two days. The established production and injection capability provides a reproducible platform for high-statistics $^42$K background studies, essential for developing and validating suppression strategies for next-generation LAr-based rare-event experiments such as LEGEND-1000.
| Search Query: arXiv Query: search_query=au:”Guenther Moritz”&id_list=&start=0&max_results=3
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