${}^{137,138,139}$La($n$, ${\hat{I}}^3$) cross sections constrained with statistical decay properties of ${}^{138,139,140}$La nuclei

Abstract

The nuclear level densities and ${\hat{I}}^3$-ray strength functions of ${}^{138,139,140}$La were measured using the ${}^{139}$La(${}^3$He, $\hat{I}\pm$), ${}^{139}$La(${}^3$He, ${}^3$He${}^{\prime }$) and ${}^{139}$La(d, p) reactions. The particle-${\hat{I}}^3$ coincidences were recorded with the silicon particle telescope (SiRi) and NaI(Tl) (CACTUS) arrays. In the context of these experimental results, the low-energy enhancement in the A$\sim$140 region is discussed. The ${}^{137,138,139}$La($n,{\hat{I}}^3)$ cross sections were calculated at $s$- and $p$-process temperatures using the experimentally measured nuclear level densities and ${\hat{I}}^3$-ray strength functions. Good agreement is found between ${}^{139}$La($n,{\hat{I}}^3)$ calculated cross sections and previous measurements.