Neutron capture cross-section measurements for $^{238}$U between 0.4 and 1.4 MeV

Neutron-induced radiative-capture cross-section data of $^{238}$U are crucial for fundamental nuclear physics as well as for Stewardship Science, for advanced-fuel-cycle calculations, and for nuclear astrophysics. Based on different techniques, there are a large number of $^{238}$U(n,$\gamma$) $^{239}$U cross-section data available in the literature. However, there is a lack of systematic and consistent measurements in the 0.1 to 3.0 MeV energy range. The goal of the neutron-capture project at TUNL is to provide accurate $^{238}$U(n,$\gamma$) $^{239}$U cross-section data in this energy range. The $^{238}$U samples, sandwiched between gold foils of the same size, were irradiated for 8-14 hours with monoenergetic neutrons. To avoid any contribution from thermal neutrons, the $^{238}$U and $^{197}$Au targets were placed inside of a thin-walled pill-box made of $^{238}$U. Finally, the whole pill-box was wrapped in a gold foil as well. After irradiation, the samples were gamma-counted at the TUNL’s low-background counting facility using high-efficient HPGe detectors. The $^{197}$Au monitor foils were used to calculate the neutron flux. The experimental technique and $^{238}$U(n,$\gamma$) $^{239}$U cross-section results at 6 energies will be discussed during the meeting.