Cross sections of the 143Nd(n,α)140Ce and 147Sm(n,α)144Nd reactions in the MeV neutron energy region

Cross sections and forward/backward ratios in the laboratory reference system were measured for the Nd-143(n,alpha)Ce-140 reaction at 4.0, 5.0, and 6.0 MeV and for the Sm-147(n,alpha)Nd-144 reaction at 5.0 and 6.0 MeV. A twin-gridded ionization chamber and large-area back-to-back (Nd2O3)-Nd-143 samples and (Sm2O3)-Sm-147 samples were employed. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University, China. Fast neutrons were produced through the H-2(d,n)He-3 reaction by using a deuterium gas target. A small U-238 fission chamber was employed for absolute neutron flux determination, and a BF3 long counter was used as the neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.