Single‐Neutron States in 101Sn

A search for γ‐ray transitions in 101Sn, which contains only one neutron outside the 100Sn core, was carried out at the Argonne Tandem‐Linac Accelerator System. 101Sn nuclei were produced using the 46Ti(58Ni,3n)101Sn reaction. In‐beam γ rays were detected in the Gammasphere Ge‐detector array and were correlated with 101Sn β‐delayed protons using the Recoil‐Decay Tagging method. A γ‐ray line at 172 keV was assigned to 101Sn and was interpreted as the transition between the single‐neutron g7/2 and d5/2 states. The measured νg7/2‐ν d5/2 energy splitting is compared with predictions of various mean‐field potentials. It is also used to calculate multi‐neutron configurations in light Sn isotopes. Prospects of using β‐delayed protons for tagging other exotic nuclei in the 100Sn region are discussed.