Measurement of the activation cross-sections of (n,np+d) reactions for lanthanide isotopes in the energy range between 13.4 and 14.9 MeV

The activation cross-sections for nine (n,np+d) reactions were measured by the activation method in the energy range between 13.4 and 14.9 MeV. The irradiated targets were lanthanide isotopes: 146,148Nd, 152Sm, 155, 158Gd, 164Dy, 170Er, and 174,176Yb. The cross-sections, except for 170Er, were obtained for the first time. The D–T neutron source of the fusion neutronics source (FNS) at the Japan Atomic Energy Research Institute was used for irradiation. All cross-section values were determined relative to that of the 27Al(n,α)24Na reaction (ENDF/B-VI). To obtain reliable activation cross-sections, careful attention was paid to the corrections of the neutrons irradiation and induced activity measurements, as well as the effective neutron energy determination at the irradiation positions. To measure weak activities, a highly efficient measuring technique with a well-type HPGe detector was applied. The present results were compared with the comprehensive evaluated data in the JENDL-3.2, JENDL-Activation File, ENDF/B-VI and FENDL/A-2.0. Most of the evaluated data were overestimated or underestimated by more than 30%. Especially, there were the large underestimations for 164Dy, 170Er, 174Yb and 176Yb in FENDL/A-2.0.