Results of a direct search using synchrotron radiation for the low-energy ${}^{229}$Th nuclear isomeric transition

Abstract

We report the results of a direct search for the ${}^{229}$Th ($I^p=3/2^{+}\leftarrow 5/2^{+}$) nuclear isomeric transition, performed by exposing ${}^{229}$Th-doped LiSrAlF${}_6$ crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between $7.3eV$ and $8.8eV$ with transition lifetime $(1-2)s\lesssim \tau \lesssim (2000-5600)s$. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.

arXiv comment6 pages, 4 figures

Cited by in corpus (6)

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• Expanding Nuclear Physics Horizons with the Gamma Factory
• Estimation of radiative half-life of ${}^{229m}$Th by half-life measurement of other nuclear excited states in ${}^{229}$Th