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

Cross sections and forward/backward ratios in the laboratory reference system were measured for the {sup 143}Nd(n,{alpha}){sup 140}Ce reaction at 4.0, 5.0, and 6.0 MeV and for the {sup 147}Sm(n,{alpha}){sup 144}Nd reaction at 5.0 and 6.0 MeV. A twin-gridded ionization chamber and large-area back-to-back {sup 143}Nd{sub 2}O{sub 3} samples and {sup 147}Sm{sub 2}O{sub 3} 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 {sup 2}H(d,n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was employed for absolute neutron flux determination, and a BF{sub 3} long counter was used as the neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.