High-Resolution Neutron and X-Ray Imaging of Granular Materials

Abstract

AbstractHigh spatial resolution (∼13.7 mm/pixel) neutron tomography was performed on partially water-saturated compacted silica sand specimens with two different grain morphologies (round and angular) at Helmholtz Zentrum Berlin using cold neutrons at the cold neutron radiography and tomography beam line. A specimen mixed with heavy water was imaged for contrast comparison purposes. Microfocus X-ray imaging was also performed on these specimens with slightly higher resolution (∼11.2 mm/pixel) using geometric magnification to locate the solid phase (silica particle boundaries) more precisely. Image processing was performed to remove unwanted gammas detected because of the gadox scintillator used for the high-resolution neutron imaging system. The visualization of solid, gas, and liquid phases for different grain morphologies is presented at the grain level. Using dual-modal contrast possible from simultaneous use of neutrons and X-rays, the authors introduce, for the first time, an improved ability to dist...