$\text{Direct}~Q\text{-Value Determination of the}~\beta^-~\text{Decay of} ~^{187}\text{Re}$

TL;DR

This paper reports the most precise measurement of the cyclotron frequency ratio of ions related to $^{187}$Re and $^{187}$Os, calculates the electron binding-energy difference, and determines the $Q$ value for the $eta^-$ decay of $^{187}$Re.

Contribution

It provides a highly precise ion frequency ratio measurement and a new $Q$ value for $^{187}$Re decay, improving nuclear data accuracy.

Findings

Most precise ion frequency ratio measurement to date.

Calculated electron binding-energy difference of 53.5(10) eV.

Determined $Q$ value of 2470.9(13) eV for $^{187}$Re decay.

Abstract

The cyclotron frequency ratio of $^{187}\mathrm{Os}^{29+}$ to $^{187}\mathrm{Re}^{29+}$ ions was measured with the Penning-trap mass spectrometer PENTATRAP. The achieved result of $R=1.000\:000\:013\:882(5)$ is to date the most precise such measurement performed on ions. Furthermore, the total binding-energy difference of the 29 missing electrons in Re and Os was calculated by relativistic multiconfiguration methods, yielding the value of $\Delta E = 53.5(10)$ eV. Finally, using the achieved results, the mass difference between neutral $^{187}$Re and $^{187}$Os, i.e., the $Q$ value of the $\beta^-$ decay of $^{187}$Re, is determined to be 2470.9(13) eV.