Patent ID: 7409042
Filing Date: 2008-08-05
Classification: G01N

Abstract:
1. A method for detecting a potential item of interest in a target sample, the method comprising: a) providing a source of photons with an energy spectrum that overlaps a nuclear resonance in the item of interest, wherein the photons from the source are generated by at least one of: Compton scattering of photons by electrons; passage of electrons through a periodic lattice; a particle-induced reaction in a nucleus; and passage of bremsstrahlung radiation photons through at least one absorber constituting a graded filter comprising both high-Z and lower-Z materials; b) illuminating the target sample with photons from the source; c) providing at least one photon detector to measure an intensity of photons scattered from at least a portion the target sample in at least one energy channel; and d) identifying an item of interest detection event if the intensity of photons detected in at least one of the at least one energy channels of interest meets a predetermined item of interest detection criterion.