One-neutron transfer study of 135Te and 137Xe by particle-γ coincidence spectroscopy: The ν1i13/2 state at N=83

Abstract

Additional 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, 8Beγ) direct reactions in inverse kinematics. Particle-γ and particle-γ-γ coincidence measurements using CsI and HPGe 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 13/21+ states in the N=83 nuclei 135Te and 137Xe at 2108.8(9) keV and 1752.6(3) keV, respectively, and for the 31- collective octupole state observed at 3749(5) keV in 134Te(N=82) inelastic scattering, all previously unknown. While the 13/21+ state (or ν1i13/2 centroid) in 133Sn(Z=50, N=83) remains unknown, the present results provide the best empirical prediction of its energy available to date. © 2012 American Physical Society.