Single-neutron states in Sn133 and Pb209, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the (Be9, Be8) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s1/2 single-neutron hole-state candidate in Sn131 was populated by (Be9, Be10). Doubly closed-shell Sn132 (radioactive) and Pb208 (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p1/2 candidate in Sn133, new absolute cross sections for the 1h9/2 candidate in Sn133 and 3s1/2 candidate in Sn131, and new lifetimes for excited states in Sn133 and Pb209. This is the first report on excited-state lifetimes of Sn133, which allow for a unique test of the nuclear shell model and Sn132 double-shell closure.
ASJC Scopus subject areas
- Physics and Astronomy (all)