Neutron reflectometry
Reflectivity is the ratio of the reflected intensity to the incident intensity for a beam directed onto an interface or surface. The technique provides valuable information over a wide variety of scientific and technological applications including chemical aggregation, polymer and surfactant adsorption, structure of thin film magnetic systems, and biological membranes.
In the simplest case contrast matching can be employed to isolate the reflected signal from a particular adsorbate within a mixture. The signal is directly proportional to the adsorbed amount and often neutron reflectometry (NR) is the only way such quantitative information can be obtained. Building on this idea specific deuteration can be employed to vary the refractive index of components both intra and inter molecular. A set of reflectivity data for the same chemical or biological system is obtained and used to constrain a real space model of the molecular organisation with a resolution of ~0.2 nm or better.
Historically ISIS has been at the forefront of developing neutron reflectometry techniques especially those devoted to studies at the air/water interface.
