Lifetimes in ²¹⁶Ra and ²¹⁷Ra; Development of collectivity in trans-lead nuclei

Abstract

The lifetimes of the yrast 6+, 8+, 10+ and 13- states in 216Ra and the 27/ 2+ state in 217Ra have been measured using direct timing and pulsed beams. The resulting B(E2) values cannot be explained by simple shell model configurations. Analysis of these transition strengths and those from similar states in related nuclei provides evidence for a relatively smooth increase in collectivity, correlated with the product of the numbers of valence protons and neutrons outside 208Pb. Show more