Patent ID: 8660238

Claim:
A method for detecting a nuclear device in a container, wherein said nuclear device is comprised of an approximately 6-cm to 8-cm diameter sphere of high-atomic number and high-density material surrounded by a region of lower atomic number and lower density material than said sphere, said method comprising: (a) propelling said container linearly in a direction of motion through an imaging region, said imaging region; (b) emitting an x-ray cone beam of 1 to 15 MeV through said imaging region to at least one x-ray detector assembly column outside of said imaging region, each of said detector assembly columns including a line of detector elements perpendicular to said direction of motion, wherein each of said detector assemblies defines an x-ray fan beam within said x-ray cone beam and said detector elements each having an area at least 1/60 of the projected area of said sphere; (c) reading an x-ray intensity at each of said detector elements for each pixel of said imaging region as said container moves through said imaging region; (d) generating an image of said imaging region; and (e) identifying said nuclear device as the area of said image wherein a high absorption area is surrounded by a lower absorption area in said image.