New systematic features in the neutron-deficient Au isotopes

A recently developed portable, on-line capability for gamma-ray and conversion-electron spectroscopy, HIGH-TATRA is demonstrated with its application to the study of Hg-183 -> Au-183 at ISOLDE. Key details of the low-energy level scheme of the neutron-deficient nuclide Au-183 populated in this decay are presented. A broad energy germanium detector is employed to achieve this (the first-ever use of such a device in decay-scheme spectroscopy), by way of a combination of high-gain gamma-ray singles spectroscopy and gamma-gamma coincidence spectroscopy. Further, by combining the gamma-ray detectors with a liquid-nitrogen-cooled Si(Li) detector operated under high vacuum, conversion-electron singles and e-gamma coincidences are obtained. These data lead to the determination of transition multipolarities and the location of a highly converted (E0 + M1 + E2) transition in the Au-183 decay scheme, suggesting a possible new shape coexisting structure in this nucleus. Identification of new intruder and normal states fixes their relative energies in Au-183 for the first time. New systematic features in the odd-Au isotopes are presented.