Levels in ${\mathrm{Ni}}^{57}$ from the ${\mathrm{Ni}}^{58}({\mathrm{He}}^3, \alpha ){\mathrm{Ni}}^{57}$ Reaction

Levels in ${\mathrm{Ni}}^{57}$ were studied by detecting the $\alpha$ particles from the ${\mathrm{Ni}}^{58}({\mathrm{He}}^3, \alpha ){\mathrm{Ni}}^{57}$ reaction in a 24-in. diam scattering chamber using surface-barrier solid-state detectors. The $Q$ value of the reaction was measured to be 8.40±0.05 MeV. Excited levels in ${\mathrm{Ni}}^{57}$ at 0.75, 1.05, 2.55, 3.25, 3.70, 3.85, 4.25, 4.55, 4.95, 5.25, 5.57, 5.85, 6.05, 6.97, 7.15, 7.85 MeV were observed. Angular distributions of elastically scattered ${\mathrm{He}}^3$, as well as those of $\alpha$ particles leading to ground, 0.75-, 1.05-, 2.55-, 3.25-, 5.25-, 5.57-, and 6.05-MeV states have been measured. $\gamma$ rays, in coincidence with the reaction $\alpha$ particles, have also been observed with a 3 in.×4 in. NaI(Tl) crystal and analyzed with a 2-parameter pulse-height analyzer to study the decay scheme of the excited states. Distorted-wave analysis, using the Oak Ridge National Laboratory's Julie computer code, yielded the following spin assignments: ground state, $l=1\mathrm{}$; 0.75-MeV state, $l=3\mathrm{}$; 1.05-MeV state, $l=1\mathrm{}$; 2.55-, 3.25-, 5.25-, 5.57-MeV states, all $l=3\mathrm{}$; 6.05-MeV state, either $l=2\mathrm{}$ or $l=3\mathrm{}$. Relative spectroscopic factors of these states have been extracted.