Photoneutron Reaction Cross Section Measurements on 94Mo and 90Zr Relevant to the p-Process Nucleosynthesis

Abstract

The photodisintegration cross sections for the 94Mo(γ,n) and 90Zr(γ,n) reactions have been experimentally investigated with quasi-monochromatic photon beams at the High Intensity γ-ray Source (HIγS) facility of Triangle Universities Nuclear Laboratory (TUNL). Energy dependence of the photoneutron reaction cross sections was measured with high precision close to the respective neutron emission thresholds and up to 13.5 meV. These measurements contribute to a broader investigation of nuclear reactions relevant to the understanding of the p-process nucleosynthesis. The results are compared with the predictions of Hauser-Feshbach statistical model calculations using different models for the γ-ray strength function. The resulting 94Mo(γ,n) and 90Zr(γ,n) photoneutron stellar reaction rates as a function of temperature in the typical range of interest for the p-process nucleosynthesis show how sensitive the photoneutron reaction rate can be to the experimental data in the vicinity of the neutron threshold.