Scattering-related contrast signals in neutron computerized tomography and the new V12 instrument at HMI Berlin

Abstract

Double-crystal diffractometers (DCD) are widely used for structural investigations at the limit between macroscopic and microscopic inner structures of sample materials. Operating in an ultra-small-angle scattering q-range between 10 −4 and 10 −1 nm −1 structures between 50 nm and nearly 100 μm can be resolved. Hence the DCD connects the resolvable ranges of small-angle neutron scattering (SANS) instruments and neutron tomography facilities. However, the DCD does not only link the resolvable size ranges but can also be operated to yield both, q-space information on microscopic structures combined with real space information in the range of macroscopic inner structures. This method was developed in recent years at the V12 DCD at HMI by introducing refraction and ultra-small-angle neutron scattering (USANS) contrast for tomography. The new V12 DCD set-up has now been optimized to exploit all the opportunities of USANS, refraction and USANS contrast tomography and conventional attenuation contrast tomography with an intense monochromatic neutron beam. The new contrast methods will be introduced as well as the final set-up of the V12 instrument. Additionally, several examples and results achieved by the new techniques and instrument will be given.