Solving of the half-life problems for the ¹⁷⁶Lu nuclear cosmochronometer

¹⁷⁶Lu is a radioactive isotope that undergoes beta decay to ¹⁷⁶Hf with a half-life of approximately 40 billion years. Therefore, the quantities of ¹⁷⁶Lu and ¹⁷⁶Hf can be used to measure the ages of events such as supernova explosions that occurred before the formation of the solar system, and the formation of the Earth's and Moon's crusts. However, despite more than 20 groups having measured the half-life of ¹⁷⁶Lu, their results have not converged within the margin of error. To resolve this issue, we measured the half-life using a windowless 4π steradian detector. This method avoids the sources of error present in conventional measurement techniques, providing the closest value to the true half-life and the highest accuracy. This advancement is expected to enhance our understanding of the history of the solar system and various celestial bodies using ¹⁷⁶Lu. (J.P.N.)