Radiative-capture cross sections for the La139(n,γ) reaction using thermal neutrons and structural properties of La140

The nuclear level densities and γ-ray strength functions of ^138,139,140La were measured using the ¹³⁹La(³He,α), ¹³⁹La(³He,'³He), and 139La(d,p) reactions. The particle-γ 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~140 region is discussed. The ^137,138,139La(n,γ) cross sections were calculated at s- and p-process temperatures using the experimentally measured nuclear level densities and γ-ray strength functions. As a result, good agreement is found between ¹³⁹La(n,γ) calculated cross sections and previous measurements.