Patent ID: 7420175

Claim:
A method for detecting an explosive associated with an inspected item, the method comprising the steps of: distributing fast neutrons from a neutron source about the item, wherein α-particles are produced during fast generation of the neutrons from a Deuterium ion current reaction; detecting gamma radiation resulting from the distribution of neutrons about the item using a coincidence measurement of the α-particles produced during generation of the neutrons and gamma-quanta from (n, gamma) reaction; adjusting the size of a scan area of the item that is being inspected, wherein adjusting the size of the scan area of the item being inspected comprises adjusting the cross-section of a directional neutron beam by moving an α-particle detector to change the solid angle of the α-particle detector in a zooming mode; producing a gamma-spectra analysis using the coincidence measurement; and analyzing the gamma-spectra analysis to detect an explosive material associated with the item.