Fast neutron resonance radiography for homeland security

We present new experimental evidence supporting the technique of fast neutron resonance radiography (NRR). Using a set of neutron attenuation images collected at several different neutron energies, the images can be transformed into a set of elemental maps, indicating the presence and relative quantity of a fixed set of basis elements. Here we report on the construction, calibration, and results from a prototype NRR imagining system. We discuss the utility of elemental maps for automated detection of materials as well as standoff determination of chemical formulas.