Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a 82208Pb beam at E/A = 1 GeV on a 2.5 g/cm2 thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an ~ 8 mm thick perspex stopper, positioned at the centre of the RISING γ-ray detector spectrometer array. A previously unreported isomer with a half-life T1/2 = 163(5) ns has been observed in the N = 126 closed-shell nucleus 79205 Au. Through γ-ray singles and γ-γ coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be IΠ.
ASJC Scopus subject areas
- Nuclear and High Energy Physics