La structure mosaïque et sa determination

By means of X-rays the mosaic structure can only be measured in a thin region of the crystal in the neighbourhood of its surface.
As a consequence of the small absorption coëfficiënt of neutrons, neutron diffraction can be used to explore the mosaic structure of the whole crystal, even in the case of thick crystals.
In case of neutron diffraction, one measures either by divergency or by reflectivity. This last method, which we present here, appears very easy to handle and also very accurate.