Cold neutron scattering in imperfect deuterium crystals

The cross sections for cold neutron scattering in mosaic deuterium crystals have been calculated for various target structures. The theoretical results are compared with the recent experimental data obtained at the Paul Scherrer Institute (PSI) with the use of FUNSPIN beamline. It is shown that various patterns of the Bragg cross sections, which were observed in different solid D2 samples at the same temperature, can be explained by contributions from a limited number of monocrystal orientations and the mosaic spread of about 3 degrees.