Identification of new isomers in $$^{228}$$Ac: impact on dark matter searches
Abstract

We report the identification of metastable isomeric states of$$^{228}$$${}^{228}$Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the$$\beta$$$\beta$-decay of$$^{228}$$${}^{228}$Ra, a component of the$$^{232}$$${}^{232}$Th decay chain, with$$\beta$$$\beta$Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of$$^{228}$$${}^{228}$Ra as well as the relative abundance of$$^{232}$$${}^{232}$Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.

Authors:
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Publication Date:
NSF-PAR ID:
10306794
Journal Name:
The European Physical Journal C
Volume:
81
Issue:
8
ISSN:
1434-6044
Publisher:
Springer Science + Business Media
National Science Foundation
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