The four proton-hole nucleus, 204 Pt, was populated in the fragmentation of an E/A = 1 GeV 208 Pb beam. The yrast structure of 204 Pt has been observed up to angular momentum I = 10 by detecting delayed γ-ray transitions originating from metastable states. These long-lived excited states have been identified to have spin-parities of I π = (10 + ), (7 − ) and (5 − ) and half-lives of T 1/2 = 146(14) ns, 55(3) µs and 5.5(7) µs, respectively. The structure of the magic N = 126 204 Pt nucleus is discussed and understood in terms of the spherical shell model. The data suggests a revision of the two-body interaction for N = 126, Z < 82, which determines the evolution of nuclear structure towards the r-process waiting point nuclei.PACS numbers: 29.30. Kv, 23.20.Lv The evolution of the properties of atomic nuclei with respect to neutron and proton numbers is a key question of nuclear physics. The study of unstable, neutron-rich nuclei represents one of the foremost pursuits of modern nuclear physics. Over the coming decade new radioactive ion beam facilities are being built with the main objectives being to probe neutron-rich nuclei. Within recent years surprising phenomena have been observed in neutron-rich nuclei such as neutron skins, halos and dramatic changes in the ordering and spacing of energy levels [1].While the stability of the N = 82 shell gap is an active topic of research [2,3], an open question is whether or not there is a quenching of the N = 126 shell gap as protons are removed from doubly magic 208 Pb. The proton dripline has been experimentally reached up to heavy elements [4], our present knowledge of the neutron dripline is limited to light species. The part of the nuclear chart with the least information on neutron-rich nuclei is the 76 Os to 82 Pb region, with experimental knowledge on only a few isotopes. This mass region is however an ideal testing ground of nuclear theories. With the removal of just a few protons and neutrons the landscape evolves from spherical to elongated prolate through disk shaped oblate and triaxial forms [5]. Consequently the information gained on neutron-rich, N = 126 nuclei is essential for the understanding of nuclear structure in heavy nuclei. From a longer-term perspective, experi-

The low-lying structure of 188,190,192 W has been studied following β decays of the neutron-rich mother nuclei 188,190,192 Ta produced following the projectile fragmentation of a 1-GeV-per-nucleon 208 Pb primary beam on a natural beryllium target at the GSI Fragment Separator. The β-decay half-lives of 188 Ta, 190 Ta, and 192 Ta have been measured, with γ -ray decays of low-lying states in their respective W daughter nuclei, using heavy-ion β-γ correlations and a position-sensitive silicon detector setup. The data provide information on the low-lying excited states in 188 W, 190 W, and 192 W, which highlight a change in nuclear shape at 190 W compared with that of lighter W isotopes. This evolution of ground-state structure along the W isotopic chain is discussed as evidence for a possible proton subshell effect for the A ∼ 190 region and is consistent with maximization of the γ -softness of the nuclear potential around N ∼ 116.

The neutron-rich N=126 nucleus 205 Au has been populated following the relativistic energy projectile fragmentation of E/A=1 GeV 208 Pb, and studied via charged-particle decay spectroscopy. An internal decay with a transition energy of 907(5) keV and a half-life of T 1/2 =6(2) s has been identified through the observation of the corresponding K and L internal conversion electron lines. The 907 keV energy level corresponds to the πh

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β decays from heavy, neutron-rich nuclei with A ∼ 190 have been investigated following their production via the relativistic projectile fragmentation of an E/A = 1 GeV 208 Pb primary beam on a ∼2.5 g/cm 2 9 Be target. The reaction products were separated and identified using the GSI FRagment Separator (FRS) and stopped in the RISING active stopper. Gamma decays were observed and correlated with these secondary ions on an event-by-event basis such that γ ray transitions following from both internal (isomeric) and β decays were recorded. A number of discrete, β-delayed γ-ray transitions associated with β decays from