Differential phase contrast and dark field neutron imaging

Differential phase contrast imaging resolves angular deviations of a beam due to phase shifts induced by a sample and thereby enables the visualisation and three-dimensional reconstruction of the refractive index distribution of a sample additional to the attenuation coefficient addressed by conventional radiography and tomography. Two instrumental techniques, namely double crystal diffractometers and a grating interferometer setup, are suitable to detect this kind of contrast. According to the high angular resolution of these methods they are suited to additionally detect dark field contrast, i.e. (ultra) small angle scattering contrast. Magnetic fields add to the refractive index for neutrons and consequently magnetic structures can in principle also be imaged by these methods. Relations between the methods will be discussed and an overview of current developments will be given.