Statistical gamma-ray decay studies at iThemba LABS

Abstract

A program to study the γ-ray decay from the region of high-level density has been established at iThemba LABS, where a high-resolution gamma-ray detector array is used in conjunction with silicon particle-telescopes. Results from two recent projects are presented: 1) The 74 Ge(α, α γ) reaction was used to investigate the Pygmy Dipole Resonance. The results were compared to (γ, γ) data and indicate that the dipole states split into mixed isospin and relatively pure isovector excitations. 2) Data from the 95 Mo(d,p) reaction were used to develop a novel method for the determination of spins for low-lying discrete levels utilizing statistical γ-ray decay in the vicinity of the neutron separation energy. These results provide insight into the competition of (γ ,n) and (γ, γ) reactions and highlights the need to correct for angular momentum barrier effects.