Study of high spin states in 149Tb observed by the (10B,3n) reaction

Abstract

Energy levels in 149Tb have been studied by the 142Nd (10B,3n) reaction using 54 MeV 10B beams from the McMaster University FN accelerator. Excitation functions, angular distributions, prompt γ–γ coincidence, electron conversion, and linear polarization measurements were obtained. On the basis of these measurements we have identified two rotaition-aligned πh11/2 bands, a negative parity band up to spin 27/2−, and a positive parity band up to spin 27/2+. The energy spacings between levels in these bands strongly resemble those in the ground state and the 3− octupole band of the adjacent 148Gd core nucleus. Other high spin positive parity states up to spin of 41/2 are also observed. These high spin states show some evidence of rotational structure in 14 9Tb.