Isochronous mass measurements of ${T}_{z}=-1\phantom{\rule{4pt}{0ex}}fp$-shell nuclei from projectile fragmentation of $^{58}\mathrm{Ni}$
Résumé
Atomic masses of seven Tz=−1, fp-shell nuclei from V44 to Cu56 and two low-lying isomers, V44m (Jπ=6+) and Co52m (Jπ=2+), have been measured with relative precisions of 1–4×10−7 with isochronous mass spectrometry (IMS) at the Cooler Storage Ring (CSRe), Lanzhou. The masses of Cu56, Co52g,52m, and V44m were measured for the first time in this experiment. The mass excesses (ME"s) of V44, Mn48, Fe50, and Ni54 are determined with an order of magnitude improved precision compared to the literature values. Co52g,52m and Cu56 are found to be 370 and 400 keV more bound, respectively, while V44g,44m are ∼300 keV less bound than the extrapolations in the Atomic-Mass Evaluation 2012 (AME"12). The masses of the four Tz=−1/2 nuclei V45, Cr47, Mn49, and Fe51 are re-determined to be in agreement, within the experimental errors, with the recent JYFLTRAP (University of Jyväskylä, Finland) measurements or with the previous IMS measurements in CSRe. Details of the measurements and data analysis are described, and the impact of the new ME values on different aspects in nuclear structure are investigated and discussed.