SPIN CONTRAST VARIATION FOR MACROMOLECULAR RESEARCH

This lecture intends to give a didactic introduction to the method of spin contrast variation for macromolecular research. The dependence of the coherent and incoherent scattering cross sections on nuclear polarization is discussed first The next section describes the experimental prerequisites to create a high nuclear polarization in hydrogenous materials. Spin contrast variation, which has become a powerful tool to introduce large and changeable contrast in a large class of samples, is described next. Covering a field with many facets on very limited space, the material is presented selecting a few simple pictures rather than aiming at completeness. Present developments of time resolved neutron scattering experiments with potential new applications will be briefly outlined at the end.