Uniaxial press for inelastic neutron scattering

The design of a uniaxial stress apparatus used to study anharmonic effects in lattice dynamics by measurement of the change of phonon energy with strain, the temperature being fixed by the use of inelastic neutron scattering, is described. The apparatus and necessary sample preparation are discussed. By the application of uniaxial stress in various directions it is possible to obtain generalized Grueneisen factors and results on silicon are presented by way of example. (U.K.)