KleinwinkelNeutronen

KleinwinkelNeutronen, a term used in some German-language contexts, refers to the technique commonly known in English as small-angle neutron scattering (SANS). It studies the structure of materials by measuring elastic neutron scattering at small angles, providing information on features from about 1 to several hundred nanometers. The method exploits the wave nature of neutrons and their strong sensitivity to light elements such as hydrogen, making it particularly valuable for soft matter and biological samples in solution.

In a typical experiment, neutrons from a reactor or spallation source are directed through collimation optics onto a sample. Scattered neutrons are detected at small angles, yielding the scattering intensity I(q) as a function of the scattering vector q, defined by q = (4π/λ) sin(θ/2). The q-range maps to real-space length scales, with d ≈ 2π/q. Data are analyzed by model fitting, Guinier and Porod analyses, and, when appropriate, ab initio modeling. Contrast variation, often achieved by isotopic labeling such as deuteration, enhances selectivity for specific components.

Applications include polymers and colloids in solution, protein complexes, lipid membranes, and porous materials. The technique enables in situ and non-destructive measurements under ambient or physiological conditions and can probe dynamics when combined with time-resolved approaches.

Compared to small-angle X-ray scattering, SANS advantages lie in neutron contrast and penetrability in soft matter, though access to neutron facilities and generally lower flux pose practical limitations. KleinwinkelNeutronen remains a key tool in materials science, biology, and soft matter research where nanoscale structure and composition are of interest.