Exploring α- and β-decay-induced quenching of the ²²⁹Th nuclear-clock isomer in solid-state hosts

2026/07/23 by Y. Elskens, M. Athanasakis-Kaklamanakis, S. Arasada Pradeep +51
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Abstract

The radiative decay dynamics of an ensemble of ^229mTh nuclei embedded in CaF₂ and MgF₂ is investigated. The isomer is populated through β decay of ²²⁹Ac following ion implantation, and its radiative decay is detected using vacuum-ultraviolet spectroscopy and measured as a function of time. This allows to identify and quantify the quenching of the radiative-decay signal induced by α or β radiation. The quenching probability density is determined in different CaF₂ crystals and in a MgF₂ crystal, revealing differences up to two orders of magnitude between the investigated samples and a strong dependence on the host material and defect densities. The results support a microscopic mechanism mediated by charge carriers in which electronic excitations created by the decay radiation are captured near Th defects, thereby favoring non-radiative decay channels.

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