Speaker
Description
The nickel isotopes offer a unique laboratory for investigating shape evolution in the vicinity of the doubly magic N=Z nucleus, Ni (Z=N=28), which should exhibit structural properties similar to those observed in the Z=N=20 region. Indeed, observation of the SD structures was also reported in Ni and was explained as the result of multiparticle-multihole excitation, as in the case of Ca. However, recently the questions on the validity of Z/N=28 as a good magic number have been brought up, triggering the discussion on the deformation in the nickel region, including the signatures of shape coexistence. Microscopic and collective properties in the vicinity of Ni shall be evaluated with dedicated measurements of the deformation and the neighboring nuclei.
Coulomb excitation studies focused on the structure of stable Ni isotopes have been undertaken at INFN LNL and at the IJC Lab in Orsay. These, together with the recent findings from the gamma-ray and electron spectroscopy measurements reporting the unexpectedly large transition strengths for the decay of 2$_2^+$ in Ni isotopes, shall bring crucial information enabling further discussion on the electromagnetic properties of Ni nuclei.
Coulomb excitation of a $^{60}$Ni beam impinging on a $^{208}$Pb target was performed at INFN LNL, Italy, in October 2023 (experiment 23.08). The current status of the data analysis will be presented.