(n, n) study of collective excitations in Os192: Comparison with the boson models for transitional nuclei

The (n, n) reaction has been used to study low-lying collective excitations in Os192. Measurements of -ray excitation functions at incident neutron energies from 1.0 to 3.0 MeV and detailed -ray angular distributions at 2.5-MeV neutron energy have led to the placement of many new levels in a level scheme now incorporating 54 levels below 2.4 MeV. In many cases, the assignment of a unique spin-parity has been possible. The positive-parity states compare favorably with interacting boson approximation and boson expansion theory calculations, except for the 03+ excitation, which is inconsistent with predictions of both models. No negative-parity band structure is apparent. NUCLEAR REACTIONS Os192(n, n), En=1.0-3.0 MeV; measured E, I, (E, E, ). Os192 deduced levels, branching ratios, J, . Compared levels and branching ratios to theory. Enriched target, Ge(Li) detector, time-of-flight background suppression.