Absolute Decay Counting of 146Sm and 147Sm for Early Solar System Chronology.

Sm–Nd chronometers use 146 Sm and 147 Sm to determine the ages of major events in the early Solar System. Their half-lives are the most important nuclear parameters determining the accuracy of chronometry. However, the 146 Sm half-life is not well-established: the published values differ by ∼ 30%, which results in significant uncertainties in the Solar System timeline. We are re-measuring the half-lives of 146 Sm and 147 Sm using decay energy spectroscopy and metallic magnetic calorimeters to improve the accuracy of the Sm–Nd chronometers. We report recent experimental results from our first measurement of a 147 Sm source, as well as status and plans for experiments on 146 Sm. [ABSTRACT FROM AUTHOR]