Systematics of Scissors Mode in Gd Nuclei from Experiments with the DANCE Detector

Multi-step cascade γ-ray spectra from neutron capture at isolated resonances of 152,154−158Gd nuclei were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The main objective of these experiments was to obtain new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. An analysis of the data obtained shows that the scissors mode plays a significant role in the ground state transitions, as well as in the transitions populating all excited states of the studied nuclei. The estimates of the scissors mode strength indicate that for 157,159Gd this strength is significantly higher than in neighboring even–even nuclei 156,158Gd. The results are compared with the (γ,γ′) data for the ground-state scissors mode and the results from 3He-induced reactions.