γ decay to the ground state from the excitations above the neutron threshold in the 208Pb(p, p′ γ) reaction at 85 MeV

A new measurement of gamma decay from the states above the neutron threshold in Pb-208 has been performed at Cyclotron Centre Bronowice in Krakow, Poland. The main goal of the experiment was to observe the gamma decay to the ground state from the isoscalar giant quadrupole resonance (ISGQR). To this day, the only published observation of this phenomenon dates back to the late 1980s, where gamma decay to the ground state branching ratio was reported. At variance with the existing measurement using inelastic scattering of O-17, here proton inelastic scattering is employed. In particular, data were obtained for Pb-208(p, p'gamma) at 85 MeV beam energy, where gamma rays were measured for proton scattering angles 8.9 degrees, 10.7 degrees, 12.5 degrees, and 14.3 degrees. By applying a similar analysis method as in the previous experiment, the branching ratio of ISGQR gamma decay to the ground state was extracted from the data.

Automated summary

A new measurement of gamma decay from states above the neutron threshold in Pb-208 was performed in Krakow, Poland. The experiment aimed to observe gamma decay to the ground state from the isoscalar giant quadrupole resonance (ISGQR). Data obtained from proton inelastic scattering at a beam energy of 85 MeV were analyzed to extract the branching ratio of ISGQR gamma decay to the ground state.