Neutron transfer reactions on the ground state and isomeric state of a 130Sn beam

The structure of nuclei around the neutron-rich nucleus Sn-132 is of particular interest due to the vicinity of the Z = 50 and N = 82 shell closures and the r-process nucleosynthetic path. Four states in Sn-131 with a strong single-particle-like component have previously been studied via the (d, p) reaction, with limited excitation energy resolution. The Sn-130(Be-9, Be-8) Sn-131 and Sn-130(C-13, C-12) Sn-131 single-neutron transfer reactions were performed in inverse kinematics at the Holifield Radioactive Ion Beam Facility using particle-gamma coincidence spectroscopy. The uncertainties in the energies of the single-particle-like states have been reduced by more than an order of magnitude using the energies of gamma rays. The previous tentative J(pi) values have been confirmed. Decays from high-spin states in Sn-131 have been observed following transfer on the isomeric component of the Sn-130 beam. The improved energies and confirmed spin-parities of the p-wave states important to the r-process lead to direct-semidirect cross sections for neutron capture on the ground state of Sn-130 at 30 keV that are in agreement with previous analyses. A similar assessment of the impact of neutron-transfer on the isomer would require significant nuclear structure and reaction theory input. There are few measurements of transfer reaction on isomers, and this is the first on an isomer in the Sn-132 region.

Automated summary

This study experimentally investigates the nuclear structure around the neutron-rich nucleus Sn-132. The proximity to shell closures and the r-process nucleosynthetic path makes this study particularly interesting. By using particle-gamma coincidence spectroscopy, the uncertainty in the energies of single-particle states has been significantly reduced and the previous results have been confirmed. These findings are important for understanding nuclear reactions and nucleosynthesis processes.