A study of the nuclear structure of 60Ni by the [formula omitted] reactions

Abstract

Angular distributions to the ground and 16 excited states of 60Ni have been measured for the 59Co( 3He, d) 60Ni reaction at a bombarding energy of 37.7 MeV. The 59Co( 3He, 3He) 59Co angular distribution was also obtained at the same energy. Discrete sets of optical potentials are found which give good fits to the elastic scattering data. It is found that DWBA calculations give better fits to the 59Co( 3He, d) 60Ni data with a depth of the real part of the optical potential of U ≈ 170 MeV and r u ≈ 1.15 fm, than with shallower potentials. It is also found that changes in optical model parameters obtained by fitting the elastic scattering data out to 90° or 150° have very little effect on DWBA fits to the 56Co( 3He, d) 60Ni angular distributions. The angular distribution to the ground state of 60Ni is characteristic of a proton transfer of l p = 3 expected from the closing of the 1 f 7 2 proton shell. The next higher excited states show angular distributions with more than one l p value contributing, indicating that the (1 f 7 2 ) −1 ( 2 p 3 2 , 2 p 1 2 or 1 f 5 2 ) proton particle-hole configurations are mixed. An analysis of 60Ni(p, p′) 60Ni data taken at 17.9 MeV at Berkeley by Jarvis et al. has been carried out in an attempt to describe some of the inelastic proton angular distributions in terms of simple shell-model configurations. Shell-model form factors are used in distorted wave calculations, the requirement being that a particular particle-hole configuration satisfies both ( 3 He, d) and ( p, p′) data. It is noted that these configurations are still not without ambiguity.