Material Identification Using Dual Particle Interrogation

In this paper, the application of bi-modal analysis, which fuses the X-ray attenuation and photoneutron attenuation together to enhance the capability of material identification, is presented. Within a 7 MeV e-LINAC system, both X-rays and photoneutrons, which are produced by the ( γ, n) reaction of 9Be nuclei with X-rays, are delivered simultaneously. A moderation process is introduced to help retard the measurement time of photoneutrons to avoid the X-ray pulse’s interference to the neutron detector. A V(t) factor is derived from the attenuation coefficients of X-rays and photoneutrons to separate different materials. The hydrogen-wealthy materials, organic materials, low-Z, middle-Z and high-Z metals could be effectively discriminated. The preliminary bi-modal imaging result, realized with a neutron detector array of 32 3He counters and an X-ray detector array, is also presented.