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Nuclear charge radii of 55;56 Ni were measured by collinear laser spectroscopy. The obtained information completes the behavior of the charge radii at the shell closure of the doubly magic nucleus 56 Ni. The trend of charge radii across the shell closures in calcium and nickel is surprisingly similar despite the fact that the 56 Ni core is supposed to be much softer than the 48 Ca core. The very low magnetic moment μð 55 NiÞ ¼ −1.108ð20Þ μ N indicates the impact of M1 excitations between spin-orbit partners across the N; Z ¼ 28 shell gaps. Our charge-radii results are compared to ab initio and nuclear density functional theory calculations, showing good agreement within theoretical uncertainties.

An experiment was performed at the National Superconducting Cyclotron Laboratory using a 140 MeV/nucleon 48 Ca beam and a flowing-water target to produce 47 Ca for the first time with this production route. A production rate of 0.020 ± 0.004 47 Ca nuclei per incoming beam particle was measured. An isotope harvesting system attached to the target was used to collect radioactive cationic products, including 47 Ca, from the water on a cation-exchange resin. The 47 Ca collected was purified using three separation methods optimized for this work: (1) DGA extraction chromatography resin with HNO 3 and HCl, (2) AG MP-50 cation-exchange resin with an increasing concentration gradient of HCl, and (3) AG MP-50 cation-exchange resin with a methanolic HCl gradient. These methods resulted in ≥99 ± 2% separation yield of 47 Ca with 100% radionuclidic purity within the limits of detection for HPGe measurements. Inductively coupled plasma-optical emission spectrometry (ICP-OES) was used to identify low levels of stable ions in the water of the isotope harvesting system during the irradiation and in the final purified solution of 47 Ca. For the first time, this experiment demonstrated the feasibility of the production, collection, and purification of 47 Ca through isotope harvesting for the generation of 47 Sc for nuclear medicine applications.