The use of contrast variation in the specular reflection of neutrons from interfaces

Several of the useful results of the kinematic approximation are presented and applied to experimental data. From the kinematic equations it is shown that contrast variation in neutron reflection can be used to obtain a scattering length density profile across an interface unique within the limitations of resolution. It is shown to be more important for two component systems to obtain actual density profiles. Contrast variation is the only way to achieve this and an illustrative example is analysed in terms of the kinematic approximation. (orig.)