Radiography and tomography with polarized neutrons

Neutron imaging became important when, besides providing impressive radiographic and tomographic images of various objects, physical, quantification of chemical, morphological or other parameters could be derived from 2D or 3D images. The spatial resolution of approximately 50 µm (and less) yields real space images of the bulk of specimens with more than some cm3 in volume. Thus the physics or chemistry of structures in a sample can be compared with scattering functions obtained e.g. from neutron scattering. The advantages of using neutrons become more pronounced when the neutron spin comes into play. The interaction of neutrons with magnetism is unique due to their low attenuation by matter and because their spin is sensitive to magnetic fields. Magnetic fields, domains and quantum effects such as the Meissner effect and flux trapping can only be visualized and quantified in the bulk of matter by imaging with polarized neutrons. This additional experimental tool is gaining more and more importance. There is a large number of new fields that can be investigated by neutron imaging, not only in physics, but also in geology, archeology, cultural heritage, soil culture, applied material research, magnetism, etc. One of the top applications of polarized neutron imaging is the large field of superconductivity where the Meissner effect and flux pinning can be visualized and quantified. Here we will give a short summary of the results achieved by radiography and tomography with polarized neutrons.