Speaker
Description
Neutron-capture cross sections play a vital role in our understanding of heavy element nucleosynthesis. In astrophysical processes such as the intermediate neutron-capture process and rapid neutron-capture process, element formation occurs in neutron-rich environments and involves short-lived isotopes for which capture cross sections cannot be measured via direct techniques. Instead reaction rates in these regions rely on calculations that have uncertainties up to a few orders of magnitude. Recent measurements of the $\beta$-decay of $^{94}$Rb [1], which compared the neutron-to gamma-ray-branching ratio of state decays above the neutron separation energy in $^{94}$Sr, suggest an enhanced $\gamma$-ray branch which would in turn lead to an unexpectedly large $^{93}$Sr(n,$\gamma$) cross section. If confirmed, such an enhancement could have a strong impact on our understanding of nucleosynthesis processes involving nuclei in this region. In order to investigate this potential enhancement of the $^{93}$Sr(n,$\gamma$) cross section, an experiment was performed at TRIUMF using an 8~MeV/u $^{93}$Sr beam impinging on a CD$_2$ target. The (d,p$\gamma$) coincidence data was measured using the SHARC and TIGRESS arrays. Experimental details from the measurement of $^{93}$Sr(d,p)$^{94}$Sr will be presented along with preliminary gamma-particle coincidence analysis using the Surrogate Reaction Method [2,3].
*This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.
[1]. J. L. Tain, et al. Phys. Rev. Lett. 115, 062502 (2015).
[2]. J. Escher, et al., Phys. Rev. Lett. 121, 052501 (2018).
[3]. A. Ratkiewicz, et al., Phys. Rev. Lett. 122, 052503 (2019).
