Computed tomography combined with a material decomposition technique using a compact deuterium-deuterium (D-D) fast neutron generator

Neutron cross-sections have an energy dependence which is uniquely varying according to isotopic composition. By measuring the local neutron beam attenuation of an object as a function of energy, this can be related to its elemental composition. Therefore material decomposition measurements using a deuterium-deuterium (D-D) compact fast neutron generator in an energy-selective fashion have been carried out. Previous work described determining setup-specific effective reference cross-section data for homogeneous samples. This work presents first tests of this non-destructive analysis principle in a 2D computed tomography (CT) setup using heterogeneous samples, based on the aforementioned reference cross-sections. Measurement data were collected at five angles around the neutron generator corresponding to five effective energies. At each angle a CT reconstruction was performed to obtain energy-specific CT images. These CT images were use to calculate an elemental decomposition of the samples of interest. Good agreement between theory and experiment was found for most of the samples, while the more challenging cases highlighted limitations of the technique. These first tomographic measurements are discussed along with an outlook for further developments of the technique.