Two-Proton Radioactivity ofF45e

Abstract

In an experiment at the SISSI-LISE3 facility of GANIL, the decay of the proton drip line nucleus ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ has been studied. Fragment-implantation events have been correlated with radioactive decay events in a $16\times 16$ pixel silicon-strip detector. The decay-energy spectrum of ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implants shows a distinct peak at $(1.14\pm 0.04)\mathrm{M}\mathrm{e}\mathrm{V}$ with a half-life of $T_{1/2}=({4.7}_{-1.4}^{+3.4})\mathrm{m}\mathrm{s}$. None of the events in this peak is in coincidence with $\beta$ particles. For a longer correlation interval, daughter decays of the two-proton daughter ${}^{\mathrm{43}}\mathrm{C}\mathrm{r}$ can be observed after ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implantation. The decay energy for ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ agrees nicely with several theoretical predictions for two-proton radioactivity.