Partial $\gamma$-ray production cross sections and the total radiative thermal-neutron capture cross section for the ${}^{185}\mathrm{Re}(n,\gamma ){}^{186}\mathrm{Re}$ reaction were measured using the Prompt Gamma Activation Analysis facility at the Budapest Research Reactor with an enriched ${}^{185}\mathrm{Re}$ target. The ${}^{186}\mathrm{Re}$ cross sections were standardized using well-known ${}^{35}\mathrm{Cl}(n,\gamma ){}^{36}\mathrm{Cl}$ cross sections from irradiation of a stoichiometric ${}^{\text{nat}}{\text{ReCl}}_3$ target. The resulting cross sections for transitions feeding the ${}^{186}\mathrm{Re}$ ground state from low-lying levels below a cutoff energy of $E_c=746\text{keV}$ were combined with a modeled probability of ground-state feeding from levels above $E_c$ to arrive at a total cross section of ${\sigma }_0=111\left(6\right)\text{b}$ for radiative thermal-neutron capture on ${}^{185}\mathrm{Re}$. A comparison of modeled discrete-level populations with measured transition intensities led to proposed revisions for seven tentative spin-parity assignments in the adopted level scheme for ${}^{186}\mathrm{Re}$. Additionally, 102 primary $\gamma$ rays were measured, including 50 previously unknown. A neutron-separation energy of $S_n=6179.59\left(5\right)\text{keV}$ was determined from a global least-squares fit of the measured $\gamma$-ray energies to the known ${}^{186}\mathrm{Re}$ decay scheme. The total capture cross section and separation energy results are comparable to earlier measurements of these values.

• Received 28 March 2016

DOI:https://doi.org/10.1103/PhysRevC.93.054319