X-ray and neutron complementarity

The complementary of X-ray and neutron diffraction was illustrated throughout the session, beginning with a study of magnetism in an anomalously non-superconducting member of the (RE)Ba₂Cu₃O_6+x series. The elemental specificity of resonant X-ray magnetic scattering showed unambiguously that when RE = Pr the structure is ordered. This led to the discovery of incommensurate modulation which energy resolved neutron magnetic scattering revealed to be static. A talk on spherical neutron polarimetry described measurement of sixteen quantities related to the sixteen independent correlation functions involved in the most general mixed nuclear/magnetic neutron scattering process.

An enlightening study by small angle neutron and X-ray scattering (SANS and AX) of block copolymer micelles emphasized isotope effects. Optimal information on structure is obtained by SANS from neutron contrast variation measurements. Using pure deuterated or hydrogenated solvent, the core and the corona can be measured separately, while mixtures provide information on the interference term.

A highly efficient neutron imaging plate with a dynamic range of 1:10⁵ and spatial resolution of less than 0.2 mm was described.