Identifying fissionable material

Abstract

Fissionable materials are distinguished from other high-effective atomic number materials by producing dual-energy x-ray radiation sufficient to cause fission in fissionable materials and directing the dual-energy x-ray radiation sufficient to cause fission in fissionable materials towards a physical region. X-ray radiation and a product of fission from the physical region are sensed. An absorption of the dual-energy x-ray radiation by the physical region is determined based on the sensed x-ray radiation, and whether the physical region includes fissionable material is determined based on the presence of a product of fission.

1 . A method comprising:
 directing a first type of radiation towards a physical region, the first type of radiation having a first energy;   directing a second type of radiation towards the physical region, the second type of radiation having a second energy that is higher than the first energy;   determining an absorption characteristic of the physical region based on an absorption of the first type of radiation and the second type of radiation by the physical region;   determining, from the absorption characteristic, that the physical region is a region of interest;   determining a characteristic of the region of interest;   modifying a third type of radiation based on the characteristic; and   scanning the region of interest with the modified third type of radiation.   
     
     
         2 . The method of  claim 1 , wherein determining a characteristic of the region of interest comprises determining a characteristic of a background of the physical region.