Evolution of collectivity in the N=100 isotones near Yb170

An experiment using the electronic gamma - gamma fast-timing technique was performed to measure lifetimes of the yrast states in Yb-170. The lifetime of the yrast 2(+) state was determined using the slope method. The value of t = 2.33(3) ns is in good agreement with the lifetimes measured using other techniques. The lifetimes of the first 4(+) and 6(+) states are determined using the generalized centroid difference method. The derived B(E2) values are compared to calculations done using the confined beta soft model and show good agreement with the experimental values. These calculations were extended to the isotonic chain N = 100 around Yb-170 and show a good quantitative description of the collectivity observed along it.