Knowledge Bank

In this work, we report the measurement of the acoustic modes in $KN3$ along two directions ($00\xi$) and ($\xi \xi 0$). The measurement is accomplished using the technique of coherent inelastic neutron scattering. The instrument used in the experiment is the triple axis spectrometer in both the constant Q and constant E modes. The sample consisted of a composite of 26 crystals aligned by means of neutron diffraction and glued together to form a cube $\sim 112$ inches on a side. The crystals were grown by slow evaporation from a water solution. The results of the measurement are compared with a calculation using the rigid ion model.