Crystal ball studies of giant resonance gamma decay

We have carried out coincidence experiments to investigate the photon and neutron emission from the giant resonance region in /sup 208/Pb and /sup 90/Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. States in /sup 208/Pb and 90Zr were excited by inelastic scattering of 380-MeV 17O. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying stats as a function of excitation energy in /sup 208/Pb to ∼15 MeV. Especially interesting observations include the absence of a significant branch from the giant quadrupole resonance to the 3- state at 2.6 MeV, a strong branch from this resonance to a 3- state at 4.9 MeV, and the dominance of decays to various 1- states at 5--7 MeV from the region around 14 MeV of excitation (E0 resonances). Comparable but less complete data were also obtained on 90Zr