Mobile associated particle imaging system

Associated Particle Imaging (API) is a technique that employs a small deuterium accelerator to accelerate deuterons into a tritium-impregnated target, producing coincident neutrons (at 14.1 MeV) and alpha particles (at 3.5 MeV) that travel in opposite directions. By detecting the arrival of an alpha particle on a phosphor, and its position in two dimensions (x and y), the time and direction of the neutron emission is determined. Neutrons that interact with material in their paths produce a gamma ray whose energy is characteristic of that material. From the arrival time and energy of these gammas, the elemental composition of an object can be deduced as a function of position. The authors have built a portable API system and conducted field tests. In these tests, they have identified a quantity of fertilizer hidden in a closed vehicle and the contents of some common military munition casings