Lack of evidence for shell effects in the (n, 2n) cross sections

Abstract

According to Bormann there exist strong neutron shell effects in the (n, 2n) cross sections at 14 MeV neutron energy. There seems to be no contradiction to this statement in the literature up to now. Using the same experimental values for the cross sections as Bormann did, a strong dependence of the (n, 2n) cross sections on the asymmetry factor ( N− Z)/ A is demonstrated, to which shell effects could represent only second-order corrections. While the quality of the experimental cross sections is too poor to exclude definitely small shell effects, there is certainly no clear evidence of any such effect.