Estimation of radiative half-life of ${}^{229m}$Th by half-life measurement of other nuclear excited states in ${}^{229}$Th

Abstract

We perform coincidence measurements between $\alpha$ particles and $\gamma$ rays from a ${}^{233}$U source to determine the half-lives of the excited state in a ${}^{229}$Th nucleus. We first prove that the half-lives of 42.43- and 164.53-keV states are consistent with literature values, whereas that of the 97.14-keV state (93(7) ps) deviates from a previously measured value (147(12) ps). The half-lives of 71.83- and 163.25-keV states are determined for the first time. Based on the obtained half-lives and the Alaga rule, we estimate the radiative half-life of the low-energy isomeric state (${}^{229m}$Th) to be $5.0(11)\times 10^3$ s, which is one of the key parameters for the frequency standard based on ${}^{229}$Th.

33 pages, 9 figures. 3 tables

References in corpus (6)

• Direct detection of the 229Th nuclear clock transition
• Measurement of the ${}^{229}$Th isomer energy with a magnetic micro-calorimeter
• Lifetime measurement of the ${}^{229}$Th nuclear isomer
• Energy of the ${}^{229}$Th Nuclear Clock Isomer Determined by Absolute $\gamma$-ray Energy Difference
• ${}^{229m}$Th isomer from a nuclear model perspective
• Results of a direct search using synchrotron radiation for the low-energy ${}^{229}$Th nuclear isomeric transition

Cited by in corpus (4)

• Atlas of Nuclear Isomers -- Second Edition
• Controlling ${}^{229}$Th isomeric state population in a VUV transparent crystal
• Ground-state $g$ factor of highly charged ${}^{229}$Th ions: an access to the M1 transition probability between the isomeric and ground nuclear states
• Production and chemical separation of ${}^{229}$Pa toward observation of $\gamma$ rays of ${}^{229\mathrm{m}}$Th