A new frontier: neutron-shell structure below Pb along N=127 isotone via the ²⁰⁶Hg(d,p) reaction.

The single-particle structure of the N=127 isotones below ²⁰⁹Pb has hitherto remained unexplored. In a first exploration of this region, single-neutron excitations in ²⁰⁷Hg have been measured via ²⁰⁶Hg(d,p) reaction in inverse kinematics. The ²⁰⁶Hg beam was produced at the ISOLDE facility at an energy of 7.4 MeV/u. The energy and position of outgoing protons were measured by the new ISOLDE Solenoidal Spectrometer (ISS) at a field of 2.5 T. Seven states have observed in ²⁰⁷Hg. Angular distributions suggest that these states are carry components of the 0g_9/2, 2d_5/2, 3s_1/2, 2d_3/2 and 0g_7/2 strength. Aside from the 2d_5/2 strength, which is strongly fragmented, the states represent close to the total single-neutron strength for each orbital.