# High precision half-life measurement of $^{147}$Sm $\alpha$ decay from thin-film sources

## TL;DR

This study precisely measured the half-life of $^{147}$Sm alpha decay using ultra low-background detection and produced natural samarium samples with pulsed laser deposition, providing new insights into its decay properties.

## Contribution

It presents the first precise half-life measurement of $^{147}$Sm alpha decay and sets a new lower limit for decay into the first excited state, using innovative sample preparation and detection methods.

## Key findings

- Half-life of $^{147}$Sm measured as 1.079(26)×10^{11} years.
- Lower half-life limit for decay to excited state: >3.1×10^{18} years.
- Samples produced via pulsed laser deposition in ultra high vacuum.

## Abstract

An investigation of the {\alpha}-decay of $^{147}$Sm was performed using an ultra low-background Twin Frisch-Grid Ionisation Chamber (TF-GIC). Four natural samarium samples were produced using pulsed laser deposition in ultra high vacuum. The abundance of the $^{147}$Sm isotope was mea- sured using inductively coupled plasma mass spectrometry. A combined half-life value for 147Sm of $1.079(26)\times{}10^{11}$ years was measured. A search for the {\alpha}-decay into the first excited state of $^{143}$Nd has been performed using $\gamma$-spectroscopy, resulting in a lower half-life limit of $T_{1/2} > 3.1 \times{}10^{18}$ years (at 90% C.L.).