Feasibility study of using a compact deuterium-deuterium (D-D) neutron generator for energy-selective transmission tomography

This article presents a feasibility study of using a compact deuterium-deuterium (D-D) fast neutron generator for element-sensitive fast neutron tomography. The energy range of such neutron generators is quasi-monoenergetic from about 2.2–2.8 MeV, depending on the angle of emission. Unlike X-rays and gamma photons, fast neutron cross-sections have unique energy sensitivity in this range depending on the nuclide, making differentiation of materials in principle possible by performing tomographic attenuation measurements at multiple energies. In this context, detailed neutron spectrum models were created and attenuation versus emission angle data were simulated for several uniform test samples. An automated mechanical apparatus and plastic scintillator fast neutron detectors were used to interrogate these samples over the full range of emission angles around a custom neutron generator located at the Paul Scherrer Institute. The experimental attenuation data were compared with simulations. Simulations and experiments were found to be generally in good agreement, demonstrating the fundamental feasibility of the approach.