Search for trends in total neutron cross sections

Abstract

A survey of total neutron cross sections at 14 MeV suggests the existence of different trends in the data. In order to determine the reliability of data given by different authors, a statistical evaluation has been carried out. It was found that the deviation in the data, measured in different laboratories for the same nuclei, is about one per cent higher than the given limits of error. A simple empirical expression is given to describe the smooth oscillating deviations of measured values from the “black-nucleus” formula as a function of mass number. Experiments were performed under the same circumstances to search for the possible fine trends or systematic behaviour in the cross-sections, e.g.N−Z dependence, odd-even effect, correlation between nuclear radii and binding energies. The experiments were carried out in the “good geometry” arrangement at 14,7 MeV neutron energy. Total neutron cross-sections were determined for N, O, Ar, Ca, Co, Ni, Cu, Zn, Ga, Ge, J, Ce, Pb, Bi.