Patent ID: 8324588

Claim:
A method comprising: exposing a target to radiation, the target comprising an unknown substance having a first composition; detecting a response from the target due to the radiation exposure; determining one or more signatures based at least in part on the detected response; providing a template corresponding to a known substance, the known substance having a second composition; and calculating a value indicative of the similarity between the first composition of the unknown substance and the second composition of the known substance by comparing the one or more signatures with the template; wherein the one or more signatures comprise at least one of: a 0.511 MeV photon induced positron annihilation signature, a neutron response obtained from an unfiltered neutron detector, a neutron response obtained from a filtered neutron detector, a 0.87 MeV Oxygen capture signature, a 1.262 MeV Carbon capture signature, a 1.64 MeV Nitrogen inelastic scatter signature, a 1.885 MeV Nitrogen capture signature, a 2.184 MeV Oxygen capture signature, a 2.223 MeV Hydrogen capture signature, a 2.31 MeV Nitrogen inelastic scatter signature, a 4.43 MeV Carbon inelastic scatter signature, a 4.945 MeV Carbon, capture signature, a 5.11 MeV Nitrogen inelastic scatter signature, a 6.128 MeV Oxygen inelastic scatter signature, or a 10.83 MeV Nitrogen capture signature.