Critique on the measurement of neutron cross-sections by the Deep Inelastic Neutron Scattering technique

Abstract

We analyze a recent work of Mayers and Abdul-Redah,[J.Phys.: Condens. Matter {\bf 16}, 4811 (2004)] in which the autors report the existence of anomalous neutron cross sections in several systems. In the present work we show that the Deep Inelastic Neutron Scattering (DINS) results presented by the authors are affected by an inaccurate formalism employed for obtaining nuclear momentum distributions, and therefore definitive conclusions cannot be drawn on the subject of anomalous cross sections. We also show the reasons why the exact formalism for obtaining momentum distributions that we recently published must be employed for analysing the experimental data instead of the approximations performed in the mentioned work. We also point out serious inconsistencies between different results reported in the mentioned work, as well as incompatibilities with previous results published by the authors. These inconsistencies, as well as experimental evidence against the existence of anomalous cross sections not considered by the authors, reinforce the need to revise critically the procedures on which the usual DINS data analysis is based as well as the proper characterisation of the experimental set-up.