research papers
The different methods of data acquisition and representation in neutron reflectometry measurements are discussed. The different representations of diffuse scattering are compared and the off-specular features that can be observed in neutron reflectivity are described. The representation of diffuse data in the `natural' reciprocal-space coordinates (Qx, Qz) leads to a loss of information for small Qz scattering vector. It is suggested that an intermediate representation (Qx/Qz, Qz) allows the unification of data measured on different types of spectrometers and permits a straightforward comparison and understanding while keeping all the interesting features of the off-specular scattering. The discussion is illustrated by diffuse scattering data measured on neutron waveguides obtained on both fixed-wavelength and time-of-flight spectrometers. A simple procedure allowing for dense remapping between different representations is described.