Re187(γ,n) cross section close to and above the neutron threshold

Abstract

The neutron capture cross section of the unstable nucleus $^{186}\mathrm{Re}$ is studied by investigating the inverse photodisintegration reaction $^{187}\mathrm{Re}$($\ensuremath{\gamma},n$). The special interest of the s-process branching point $^{186}\mathrm{Re}$ is related to the question of possible s-process contributions to the abundance of the r-process chronometer nucleus $^{187}\mathrm{Re}$. We use the photoactivation technique to measure photodisintegration rates. Our experimental results are in good agreement with two different statistical model calculations. Although the cross sections predicted by both models for the inverse reaction $^{186}\mathrm{Re}$($n,\ensuremath{\gamma}$) is too low to remove the overproduction of $^{186}\mathrm{Os}$; the two predicted neutron-capture cross sections differ by a factor of $2.4$; this calls for future theoretical study.