Exploration of the dynamics of condensed matter through neutron total cross-section measurements

We present a novel procedure to extract dynamical information from the inel astic incoherent part of the experimental neutron total cross section. The coherent elastic and inelastic components must be subtracted in order to is olate the incoherent inelastic part. We show how to obtain the one-phonon d ownscattering component from it, and use this result to evaluate its deriva tive with respect to the incident neutron wave vector. This provides a func tion, which serves as an input for the algorithm to extract the density of the states that is presented in this paper. We have applied this method in the case of three metal hydrides: zircaloy, magnesium and niobium, whose to tal cross sections were measured at a low-flux neutron source. Those result s are in agreement with the inelastic scattering experiments performed at h igh-flux sources over the range from 40 to 250 meV. (C) 1999 Elsevier Scien ce B.V. All rights reserved.