Evaluation of the Experimental np-Angular Distribution at 14.1 MeV Neutron Energy

The total cross section and angular distribution of the (n,p) scattering reaction is an object for detailed experimental and theoretical investigations as a primary standard. In spite of many years efforts these data, in particular the angular distribution are not known with required accuracy. We analyzed available experimental data at ∼14 MeV and concluded that the big data spread is connected mainly with data normalization. We renormalize the original data using the following procedure. All data sets were fit by different polynomial expansions. The data of independent experiments were normalized to reach minimum χ^2. The beginning value was χ^2 = 1.47 and final value χ^2 = 0.41. The data corrections were ＜5%. The final result is insensitive to the order of polynomial expansion. The final χ^2 of 0.41 indicates that we have reduced systematic errors in the data sets, so we have reduced the error bars by a factor of 1.6. ENDF/B-7 data are in reasonable agreement with evaluated experimental data. But some problem became more visible - it seems that experimental data require stronger angular asymmetry. KCI Citation Count: 1