Beta Decay of Neutron-Rich Nucleus ²⁰⁸Hg

The β^- decaying γ scheme of the neutron-rich nuclide ²⁰⁸Hg has been determined for the first time. The ²⁰⁸Hg was produced in multi-nucleon transfer reaction taking place in the bombardment of ¹⁸O-beam on natural lead target, and the Hg-element products were separated with a gas-thermochromatography technique. The γ-ray single and γ-γ coincident spectra were measured. A partial ²⁰⁸Hg γ scheme was proposed. Twenty-six γ rays were assigned to follow the β^- decay of ²⁰⁸Hg. At the same time, a new level structure of the daughter nucleus ²⁰⁸Tl was constructed, in which three new levels at 1.72 MeV, 1.652 MeV, and 1.362 MeV were affirmed. The experimental ²⁰⁸Tl level structure was compared with a shell-model calculation.