Diffraction group (DIF)

The instruments of the Diffraction group (DIF) use neutron diffraction for studying the structure of materials used in everyday life. The latter can be in the form of liquid or amorphous materials, crystalline powders or single crystals. The atomic and/or magnetic structures of metal/alloys, mineral, organic, macromolecular or biological materials can be investigated.

Powder diffractometers

These two-axis diffractometers are used to investigate the structure of crystalline powders, liquids and amorphous materials.

Diffraction group machines use relatively short wavelength neutrons (0.3 to 2.0 Å) to resolve structures to atomic resolution, in contrast to diffractometers in the Large Scale Structures group that use long wavelength neutrons for lower resolution of larger structures. Usually a large composite monochromator, up to 300 mm high, is used to select a narrow band of wavelengths and focus it onto the sample. Large multi-detectors and linear position-sensitive detectors (PSDs) cover a large solid angle for maximum efficiency.

The high-resolution powder diffractometers D2B is used mainly for Rietveld refinement, with scans lasting from 30 minutes to several hours. They are complemented by two high-flux medium-resolution powder machines, D1B and D20, which are used mainly for temperature scans and other types of fast experiment, especially on small samples. D4, on the short wavelength hot source, is used for liquids and amorphous materials, together with D20.