Half-life Measurements of Highly Charged Radioisotopes by Nuclear Recoil in a Penning Trap

TL;DR

This paper introduces a new non-destructive method using a Penning trap to measure the half-life of highly charged radioisotopes, exemplified by $ m ^7Be^{3+}$, with high efficiency and precision, aiding astrophysical research.

Contribution

The paper presents a novel technique for measuring half-lives of highly charged isotopes via nuclear recoil detection in a Penning trap, achieving high efficiency and enabling state-dependent decay studies.

Findings

Decay detection efficiency of 99.5% demonstrated.

Achieves less than 5% statistical uncertainty with 500 decays.

First direct measurement of state-dependent decay branching ratios.

Abstract

We present a novel method for measuring the half-life of highly charged radioisotopes by non-destructive nuclear recoil detection in a Penning ion trap. A specific emphasis is placed on $\rm ^7Be^{3+}$, which plays a crucial role in stellar evolution and the production of solar neutrinos. The determination of the half-life is necessary to constrain the free electron capture rate in the solar environment, but is difficult to measure by existing techniques. Simulations of the sympathetic cooling of the recoiled daughter nuclei ($\rm ^7Li^{3+}$) with the trapped cloud of $\rm ^7Be^{3+}$ demonstrate a decay detection efficiency of $99.5\%$. A statistical analysis of half-life measurements on ensembles containing hundreds of ions shows that a final statistical uncertainty of less than $5\%$ is achieved with only 500 measured decays. By coherent control of hyperfine populations in trapped ions, the fidelity of the technique we describe enables the direct measurement and manipulation of state-dependent decay branching ratios for the first time.