First Measurement of the $^{96}$Ru(p,$\gamma$)$^{97}$Rh Cross Section for the p-Process with a Storage Ring

TL;DR

This study introduces a novel storage ring technique to directly measure the $^{96}$Ru($p, \,\gamma$)$^{97}$Rh cross section, providing valuable data for nuclear astrophysics and reaction modeling.

Contribution

It demonstrates a new method for measuring reaction cross sections on unstable nuclei using a storage ring, improving reaction rate constraints for the p-process.

Findings

Measured the $^{96}$Ru($p, \,\gamma$)$^{97}$Rh cross section between 9 and 11 MeV.

Pinned down the $\\gamma$-ray strength function and level density model.

Provided a constrained reaction rate for p-process network calculations.

Abstract

This work presents a direct measurement of the $^{96}$Ru($p, \gamma$)$^{97}$Rh cross section via a novel technique using a storage ring, which opens opportunities for reaction measurements on unstable nuclei. A proof-of-principle experiment was performed at the storage ring ESR at GSI in Darmstadt, where circulating $^{96}$Ru ions interacted repeatedly with a hydrogen target. The $^{96}$Ru($p, \gamma$)$^{97}$Rh cross section between 9 and 11 MeV has been determined using two independent normalization methods. As key ingredients in Hauser-Feshbach calculations, the $\gamma$-ray strength function as well as the level density model can be pinned down with the measured ($p, \gamma$) cross section. Furthermore, the proton optical potential can be optimized after the uncertainties from the $\gamma$-ray strength function and the level density have been removed. As a result, a constrained $^{96}$Ru($p, \gamma$)$^{97}$Rh reaction rate over a wide temperature range is recommended for $p$-process network calculations.