First application of combined isochronous and Schottky mass spectrometry: Half-lives of fully ionized Cr 24 + 49 and Fe 26 + 53 atoms

Lifetime measurements of $\ensuremath{\beta}$-decaying highly charged ions have been performed in the experimental storage ring (CSRe) by applying the isochronous Schottky mass spectrometry. The fully ionized $^{49}\mathrm{Cr}$ and $^{53}\mathrm{Fe}$ ions were produced in projectile fragmentation of $^{58}\mathrm{Ni}$ primary beam and were stored in the CSRe tuned into the isochronous ion-optical mode. The new resonant Schottky detector was applied to monitor the intensities of stored uncooled $^{49}\mathrm{Cr}^{24+}$ and $^{53}\mathrm{Fe}^{26+}$ ions. The extracted half-lives ${T}_{1/2}(^{49}\mathrm{Cr}^{24+})=44.0(27)$ min and ${T}_{1/2}(^{53}\mathrm{Fe}^{26+})=8.47(19)$ min are in excellent agreement with the literature half-life values corrected for the disabled electron capture branchings. This is an important proof-of-principle step towards realizing the simultaneous mass and lifetime measurements on exotic nuclei at the future storage ring facilities.