Proton Inelastic Scattering on $^{74}$Ni

The proton inelastic scattering on the neutron-rich nucleus $^{74}$Ni has been investigated aiming at exploring the evolution of the magicity at $Z$=28 in a very neutron-rich region. In the Ni isotopes lighter than $^{72}$Ni, the first 2$^{+}$ states are located higher than those of the neighboring isotones, reflecting the magicity at $Z$=28. In the present experiment, the excitation energy of the first 2$^{+}$ state ($E_{x}(2^{+}) $) and the deformation parameter of a more neutron-rich Ni isotope $^{74}$Ni were measured by proton inelastic scattering. $^{74}$Ni was produced at NSCL by the projectile fragmentation of a 140 MeV/nucleon $^{86}$Kr beam on a $^{9}$Be target. The $^{74}$Ni beam impinged on a liquid hydrogen (LH$_{2}$) target and the NaI(Tl) scintillator array (APEX) placed around the LH$_{2}$ target detected the de-excitation $\gamma$ rays. $E_{x}(2^{+})$ was determined from the $\gamma$-ray spectrum measured in coincidence with the scattered $^{74}$Ni ions. The deformation parameter was extracted from the angle-integrated cross section.