Investigating the nature of the Er isotopes with (p, t) reactions

Abstract

A series of (p, t) reactions have been performed at the Maier-Leibnitz Laboratory using beams of 22 or 24 MeV protons, and the reaction products were analysed with the Q3D spectro-graph. The goals of the measurements were to investigate the population of low-lying states in 160, 162, 164, 166Er. A number of low-lying 0+ states have been observed, and their population strengths relative to the ground states extracted. The results confirm the strong population of the 0+2 state in 164Er observed previously, and that the 0+2 states in 160,162Er are also strongly populated, with strengths in the range of 13% to 20% relative to the ground state population. The strength in 160Er is consistent with that observed in other N = 92 isotones, and suggest a common structural feature, possibly related to shape coexistence and the role that the 121- [505]ν configuration is playing in the 0+2 states in the N = 90 isotones.