First evidence of low energy enhancement in Ge isotopes

Abstract

The γ-strength functions and level densities of ^73,74Ge have been extracted from particle-γ coincidence data using the Oslo method. In addition the γ-strength function of ⁷⁴Ge above the neutron separation threshold, S_n = 10.196 MeV has been extracted from photoneutron measurements. When combined, these two experiments give a γ-strength function covering the energy range of ∼1-13 MeV for ⁷⁴Ge. This thorough investigation of ⁷⁴Ge is a part of an international campaign to study the previously reported low energy enhancement in this mass region in the γ-strength function from ∼3MeV towards lower γ energies. The obtained data show that both ^73,74Ge display an increase in strength at low γ energies.