Measurements of the ${}^{96}$Zr($\hat{I}\pm$,n)${}^{99}$Mo cross section for astrophysics and applications

Abstract

The reaction ${}^{96}$Zr($\hat{I}\pm$,n)${}^{99}$Mo plays an important role in $\hat{I}½$-driven wind nucleosynthesis in core-collapse supernovae and is a possible avenue for medical isotope production. Cross section measurements were performed using the activation technique at the Edwards Accelerator Laboratory. Results were analyzed along with world data on the ${}^{96}\mathrm{Zr}(\hat{I}\pm ,n)$ cross section and ${}^{96}\mathrm{Zr}(\hat{I}\pm ,\hat{I}\pm )$ differential cross section using large-scale Hauser-Feshbach calculations. We compare our data, previous measurements, and a statistical description of the reaction. We find a larger cross section at low energies compared to prior experimental results, allowing for a larger astrophysical reaction rate. This may impact results of core-collapse supernova $\hat{I}½$-driven wind nucleosynthesis calculations, but does not significantly alter prior conclusions about ${}^{99}\mathrm{Mo}$ production for medical physics applications. The results from our large-scale Hauser-Feshbach calculations demonstrate that phenomenological optical potentials may yet be adequate to describe $(\hat{I}\pm ,n)$ reactions of interest for $\hat{I}½$-driven wind nucleosynthesis, albeit with regionally-adjusted model parameters.

accepted to PRC