Patent ID: 8357910

Claim:
A method for interrogating an Area Under Investigation (AUI) with a neutron beam, causing gamma rays to be fluoresced from multiple substances in multiple locations within the AUI, possibly including from one or more substances of interest within the AUI, said method comprising the steps of: providing an agile neutron source; producing a neutron beam from the neutron source, the neutron beam having a definable flux attribute (φ Illumination ); assessing the distance from the neutron source to the AUI; illuminating the AUI with the neutron beam; detecting useful fluorescence gamma ray signals (φ Useful ) from the AUI in response to the neutron beam's interaction with substances present contained in the AUI, while also detecting unwanted nuisance signals (φ Background ); indiscriminately receiving the useful gamma ray signals (φ Useful ) together with the unwanted nuisance signals (φ Background ) in a detector; and modulating the neutron beam flux (φ Illumination ) to adjust the production of unwanted nuisance signals (φ Background ) to optimal levels by whereby such parameters as the signal-to-noise ratio (SNR) received by the detector or other detection parameters such as Integration Time are improved.