The ground-state bands of the neutron-rich Th236 and U242 nuclei were established up to spin 10 and 8, respectively, by in-beam γ-ray spectroscopy using the (O18, Ne20) two-proton pickup reaction with a U238 and a Pu244 target. Deexcitation γ rays in Th236 and U242 were identified by selecting the kinetic energies of Ne20 using Si ΔE-E detectors. The excitation energies of the first 2+ states in U and Pu isotopes have local minima at N 146, suggesting the possibility that nuclei with Z 92 have a spherical shell closure of N=164. Calculation using the Koura-Yamada single-particle potential gives an energy gap of 1.8 MeV at N=164 for U256.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics