Neutron Diffraction
Neutron diffraction is a process used to study the structure and arrangement of atoms within a material. It is similar to X-ray crystallography, in that both techniques use X-rays and atomic lattice planes to deflect and measure the positions of atoms within a material. The primary difference between the two techniques is that neutron diffraction works best with materials that do not contain any elements with a large atomic number (i.e. heavy elements such as uranium or thorium). This is because the amount of neutrons that can be scattered by a material is dependent on the neutron cross-section of the scattering element. Neutrons have smaller cross sections than X-rays and can interact with materials with much lower atomic numbers and even individual atoms (such as hydrogen atoms, which are found in many biological materials).
Neutron diffraction is used in a wide range of scientific and industrial disciplines, such as powder metallurgy, materials science, nanotechnology, nuclear engineering and materials characterization. The method works by sending cold neutrons, which are travelling at around 10-20 meV, into a sample. When the neutrons interact with the atoms within the sample, they are scattered in a particular pattern that is dependent on the structure and arrangement of the atoms. By using mathematical algorithms, the positions of the atoms can be determined and the structure of the material can be understood in greater detail.
Neutron diffraction is a great tool for determining the atomic structure of materials and offers unique advantages over X-ray crystallography. For example, it has a higher penetration depth than X-rays, which allows for deeper studies of thicker materials. Additionally, neutrons can differentiate between different isotopes of a single element, and can in some cases provide insight into the magnetic structure of materials. For example, in the study of polycrystalline materials, neutron diffraction can provide information about the arrangement of atoms and the degree of interatomic bonding between them. The technique can also be used to study local magnetism, providing information about magnetic moments and domain structure.
On the industrial side, neutron diffraction is used for a range of product or manufacturing process quality assurance checks. It is also used to determine the characteristics of engineering materials such as steels, as well as to identify defects in materials before they are put into production.
In conclusion, neutron diffraction is a valuable, versatile technique that is used in a range of scientific and industrial applications. It offers unique advantages over X-ray diffraction, and is an effective tool for studying both the atomic- and micro-structure of materials. The method is used in academia, industry, and government research labs around the world, and is an invaluable tool for understanding the structure of materials at the atomic level.
