Unique reconstruction of depth profiles in neutron specular reflectometry: Practical aspects

The possibility of a full determination of the reflection coefficient (modulus and phase) in neutron specular reflection is discussed. Specifically, the proposed solution of the phase problem based on polarization measurements and a magnetic reference layer is considered. A procedure and the corresponding formulae are worked out to extract the maximum of accessible information from measurements with available reflectometers, taking into account their limitations in the polarization analysis and the preparation of the beam. Albeit the incompleteness of the polarization measurements results in ambiguities of the reflection coefficient, the physical one can in most cases be identified by additional knowledge about the profile. This is shown in a schematic example with simulated incomplete data.