Collectivity in neutron-deficient Pb and Po nuclei

Abstract

Lifetimes of low-lying yrast states in 186Pb and 194Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in 188Pb up to the 8+ state were carried out using the recoil gating method. The deformation parameters $\vert \beta_{2}\vert = 0.29(5)$ and $\vert \beta_{2} \vert = 0.17(3)$ for the prolate (186,188Pb) and the oblate (194Po) bands, respectively, have been extracted from the measured lifetimes. 27.70.+q–