Speaker
Description
We are re-measuring the half-lives of $^{146}$Sm and $^{147}$Sm to improve the accuracy of Sm-Nd chronometers for early solar system chronology. The samarium sources are fully embedded into small Au foils and coupled to cryogenic microcalorimeters that measure heat released from each Sm alpha decay. This new detection method provides near 100% detection efficiency and a few keV energy resolution, which makes it well suited for accurate decay counting of low activity samples. After the decay counting is completed, the Sm sources will be chemically separated from Au foils and accurately quantified by thermal-ionization mass spectrometry with Sm standards to determine the number of Sm atoms that were embedded in each detector. Half-lives will be obtained by combining activity measurements from decay counting along with the number of atoms from mass spectrometry. We will report the $^{147}$Sm half-life from our work (figure 1), as well as progress on the $^{146}$Sm half-life measurement using the same technique.