Recoil-distance lifetime measurements of the ground-state band in 164Dy, 170Er, and 174Yb

Mean-lives of the 4+, 6+ and 8+ levels of the ground-state band in 164Dy, 170Er and 174Yb have been measured by the recoil-distance technique following multiple Coulomb excitation with 32S projectiles of energy 120-140 MeV. The gamma-rays were detected in coincidence with backscattered particles. The results are compared with theoretical predictions of the adiabatic rotor model. The 6+ and 8+ lifetimes in 164Dy are found to correspond to a slight reduction in B(E2) values over the rotational model prediction, while for for the 4+ state a 12% reduction was observed. In 170Er and 174Yb the lifetimes are consistent with rotational model predictions with a slight enhancement of B(E2) values at higher spins. Comparison with other results from Doppler broadened lineshape analysis confirms the need to adjust the electronic stopping powers of Northcliffe and Schilling in the lineshape calculations. (Author)