Abstract
The neutron capture cross section for the La-139(n, gamma)La-140 reaction at 0.0536 eV was measured for the first time using monochromatic neutrons coming from a Triple Axis Spectrometer at the TRIGA Mark-If reactor. The neutron beam intensity was determined by irradiating Au-monitor foil together La2O3 target. The radioactivity of the products was determined via high resolution gamma-ray spectrometry. The obtained cross section value is 6.13 +/- 0.3 b, which is 1.34% and 0.21% lower than that in the ENDF/B-VII and JENDL-3.3 data library, respectively.