Abstract: The present invention discloses a method for determining an atomic number of a location on a material using a radiation at a predetermined energy. The method comprises the steps of (i) generating the radiation at a first spectrum and a second spectrum penetrating through the location on the material; (ii) detecting a first profile corresponding to the first spectrum and a second profile corresponding to the second spectrum; and (iii) determining the atomic number of the material at the location based on the first profile and the second profile.

Abstract: An apparatus particularly suited to the inspection of carp in trucks, shipping containers and the like uses a beam of high energy x-rays, e.g., in the order of 8 Mev. A first detector is aligned with the beam to detect x-rays that have passed directly through the cargo. A second detector, located adjacent the first detector, receives x-rays that are inelastically forward scattered from the cargo at an angle in the range of 4.degree. to 10.degree.. Comparison of the relative amounts of x-ray received at each of these detectors with values for known materials identifies the nature of the cargo. The beam is fan-shaped and preferably vertical, and the detectors are preferably linear arrays of detector elements. Collimators define the field of view of the two detector arrays so that they both include a common spatial location within the cargo.

Abstract: A coil for a metal detector is constructed from a ribbon cable having a plurality of spaced parallel conductors. The ribbon is formed into a loop where its opposing ends confront each other. The conductors are joined in an off-set manner at the end of the cable to form a single conductor into a loop. Various configurations of coil placement are shown to compensate for various external disturbances such as nearby metal objects, for example.