Neutron Kikuchi Effect: A New Method for Measuring Phonon Dispersion Curves

Abstract

Secondary Bragg scattering of neutrons which have already undergone inelastic scattering from a phonon will give rise to sharp changes in inelastic neutron scattering intensity near a Bragg peak. The effect should be observable, and the energy and momentum of the phonon can be found by a suitable experimental setup. Special attention is given to acoustic phonons and questions of resolution are discussed.

Observation of Kossel and Kikuchi Lines in Thermal Neutron Incoherent Scattering

“…Thermal neutron K lines have been predicted theoretically, both for dynamical scattering [7], and due to incoherent elastic scattering [8]. Despite these predictions and to the best of our knowledge, they have never been identified in experimental thermal neutron scattering data.…”

“…In 1983, Wilkins proposed the observation of K lines using neutrons that had undergone inelastic diffuse scattering from phonons [7]. An experiment relevant to the theory by Wilkins was carried out by Town, Smith, and Elcombe [9].…”