Cross-sections of the ²³⁸U (n, γ) ²³⁹U reaction in the 3.0–7.0 MeV energy region measured by relative activation method*

Abstract The reaction cross-sections of 238 U ( n , γ ) 239 U have been experimentally determined at neutron energies of 6.117 ± 0.119 MeV, 4.626 ± 0.086 MeV, and 3.622 ± 0.348 MeV employing the relative activation approach along with the off-line γ-ray spectroscopy method. The D ( d , n ) 3 He reaction was utilized to obtain monoenergetic neutrons of the required energy, and the 197 Au ( n , γ ) 198 Au reaction cross-sections were adopted as the referential standard to ascertain the neutron capture cross-sections of 238 U. Furthermore, the effects of low-energy scattered neutrons, neutron fluence fluctuations, counting of geometric corrections when measuring γ -rays, and neutron and γ -ray self-absorption caused by the sample thickness have been considered and revised in the present work. For a comparison with experimental results, the cross-sections of the 238 U ( n , γ ) 239 U reaction were calculated theoretically with the original parametric TALYS-1.9 program. The experimental measurements were in contrast to previous experimental results and the evaluation data available for ROSFOND-2010, CENDL-3.2 and ENDF/B-VIII.0.