Photoneutron reaction cross section measurements on 94Mo and 90Zr relevant to the p-process nucleosynthesis

TL;DR

This study measures the photoneutron reaction cross sections of 94Mo and 90Zr using quasi-monochromatic gamma-ray beams, providing data crucial for understanding the nuclear processes involved in p-process nucleosynthesis.

Contribution

It provides high-precision experimental data on photoneutron cross sections for 94Mo and 90Zr, and compares these with theoretical models to improve reaction rate predictions.

Findings

Cross sections measured from neutron threshold up to 13.5 MeV.

Reaction rates are highly sensitive to experimental data near the neutron threshold.

Comparison with models highlights the importance of gamma-ray strength functions.

Abstract

The photodisintegration cross sections for the 94Mo({\gamma},n) and 90Zr({\gamma},n) reactions have been experimentally investigated with quasi-monochromatic photon beams at the High Intensity {\gamma}-ray Source (HI{\gamma}S) facility of the Triangle Universities Nuclear Laboratory (TUNL). The energy dependence of the photoneutron reaction cross sections was measured with high precision from the respective neutron emission thresholds 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 two different models for the dipole {\gamma}-ray strength function. The resulting 94Mo({\gamma},n) and 90Zr({\gamma},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 stellar reaction rate can be to the experimental data in the vicinity of the neutron threshold.