Furthermore, they can be favorably considered for CAT scanning and gamma-ray camera operation. The authors said the principle advantages of this material over Si and Ge are its relatively high stopping power and room- temperature operation. The monolithic structure was chosen to keep fabrication costs down. The first stage is sensitive to explosives and other suspicious items, allowing for high throughput. The second stage is based on x-ray diffraction and provides complementary information on the objects.
Most current systems distinguish between organic, aluminum or mixed matter, and heavy materials.
The first stage of the new system achieves much greater differentiation by using multiple x- ray energies and appropriate data processing. For example, plastic explosives can be distinguished from all other commonly used plastics. Suspicious luggage is passed to stage two, in which the diffraction pattern of x rays passing through the material is analyzed spectroscopically. The crystalline structure of explosives will produce an identifiable spectrogram, and multiple materials in the path of the beam can be distinguished. The authors foresee a much greater degree of reliability of the two- stage system over current systems.