Advanced x-ray detectors may improve nuclear screening

Nature : Airport x-ray machines can’t distinguish between materials of similar density. A computer model created by Andrew Gilbert of the University of Texas at Austin and his colleagues suggests that spectral radiography, a type of x-ray detection used in medicine, may provide an alternative screening method that can make that distinction. In spectral radiography, the energy of individual photons is measured after they pass through a series of materials. Beer’s law can then be used to determine the properties of the various materials. Gilbert’s team ran their model against simulations of layered plutonium, steel, and cotton and found that the model was able to not only identify the materials but also estimate their thickness. The next step will be to perform real-world tests. If successful, the method could be adapted to help security screeners differentiate nuclear materials from innocuous materials of similar densities.