Neutron Scattering from MgO

The single differential angular scattering cross section of neutrons from a single crystal of magnesium oxide has been measured and calculated using a lattice-dynamical model. A shell model with interactions to second neighbors has been used to calculate the frequencies, polarization vectors, and gradients of the frequencies. Scattering experiments have been made using a pulsed source of neutrons obtained with a linear electron accelerator. To compare the measured angular distributions with the theory, the one-phonon coherent cross section has been computed using a formula given by Waller and Fr\"oman. Measurements and computations of the single differential cross sections are presented at four different orientations of the single crystal for scattering processes in a main symmetry plane.