Abstract
New information is reported on single-neutron states above the doubly closed-shell nucleus 132Sn.
A radioactive ion beam of 134Te(N = 82) at 565 MeV and a stable ion beam of 136Xe(N = 82) at 560 MeV were used to study single-neutron states in the N = 83 nuclei 135Te and 137Xe, respectively, by (13C, 12Cγ) and (9Be, Beγ) direct reactions in inverse kinematics. Particle-γ and particle-γ-γ coincidence measurements using HPGe and CsI arrays allowed determination of decay paths, high-precision level energies, multipolarities of transitions, and relative cross sections. One-neutron transfer with heavy ions is employed to gain selectivity to both low- and high-spin single-neutron states above the N = 82 shell closure. Results are presented for the 13/2+ states in the N = 83 nuclei 135Te and 137Xe at 2108.8(9) keV and 1752.6(3) keV, respectively, and for the 3− collective octupole state observed at 3749(5) keV in 134Te(N = 82) inelastic scattering, all previously unknown. While the 13/2+ state (or 1i13/2 centroid) in 133Sn(Z = 50, N = 83) remains unknown, the present results provide the best empirical measure of its energy available to date.
