Neutron Total Cross Sections, 2.5-15 MeV. I. Experimental

We have completed measurements of the total cross section, for neutrons between 2.5 and 15 MeV, of 78 natural elements and 14 artificial or isotopically enriched samples spanning the range from hydrogen to plutonium. The measurements were made by transmission in good geometry (inscattering $\mathrm{Li}(d,n)$ source. Data were taken with moderate energy resolution (2 to 4%) and moderate precision (1 to 3% at each point) at a density of three or four points per resolution interval, in order to avoid leaving gaps. We believe systematic errors do not exceed 2%, except in particular cases. Our method leads naturally to small samples, so that we were able to include all of the stable elements except the noble gases. The resulting homogeneous set of data supplies a reference surface for the intercomparison of results from other laboratories. We have made detailed comparisons with virtually all previous measurements in this energy range, and we summarize the systematic properties of the major ones. The completeness of the set helps to reveal a number of systematic properties of the interaction of fast neutrons with nuclei over the entire range of masses.