Results of decay spectroscopy on nuclei in the vicinity of the doubly magic ${}^{48}\mathrm{Ni}$ are presented. The measurements were performed with a time projection chamber with optical readout which records tracks of ions and protons in the gaseous volume. Six decays of ${}^{48}\mathrm{Ni}$, including four events of two-proton ground-state radioactivity, were recorded. An advanced reconstruction procedure yielded the $2p$ decay energy for ${}^{48}\mathrm{Ni}$ of $Q_{2p}=1.29\left(4\right)$ MeV. In addition, the energy spectra of $\beta$-delayed protons emitted in the decays of ${}^{44}\mathrm{Cr}$ and ${}^{46}\mathrm{Fe}$, as well as half-lives and branching ratios, were determined. The results were found to be consistent with the previous measurements made with Si detectors. A new proton line in the decay of ${}^{44}\mathrm{Cr}$ corresponding to the decay energy of 760 keV is reported. The first evidence for the $\beta 2p$ decay of ${}^{46}\mathrm{Fe}$, based on one clear event, is shown.

• Received 30 May 2014

DOI:https://doi.org/10.1103/PhysRevC.90.014311