First phase-contrast tomography with thermal neutrons

Attenuation-contrast tomography with monochro-matic thermal neutrons becomes a standard tool at many places in the world. A new tomographic neutron technique-the inter-ferometric imaging or neutron phase-contrast tomography (nPCT)-is introduced. nPCT is similar to x-ray phase-contrast tomography (xPCT) and offers a complete three-dimensional (3-D) investigation of the attenuation, the small angle scattering, and the phase-shifting properties of isotope distributions in the sample. As a first demonstration of the feasibility of nPCT, an aluminum screw has been imaged in an aluminum block of slightly different composition. A spatial resolution of 100 μm has been achieved and the high sensitivity of phase-contrast measurements with thermal neutrons was verified.