Shape co-existence and structural evolution of the yrast band in 157Yb

Abstract

The high-spin states of 157Yb have been studied via the 144Sm(16O, 3n) reaction at 16O energy of 90 MeV using techniques of in-beam γ-ray spectroscopy. Measurement of γ-γ-t coincidences was performed with 11 BGO(AC)HPGe detectors. Based on the measured results of γ-γ coincidences, γ-ray anisotropies and DCO ratios, the level scheme for 157Yb was established. The shape co-existence and structural evolution of the νi 13/2 band with increasing angular momentum in 157Yb have been discussed. The systematics of the νi 13/2 bands in the N = 87 odd-A isotones have been compared.