Abstract: Apparatus and methods for imaging sources of gamma rays with a large area, comparatively low-cost Compton telescope (20). The Compton telescope (20) uses multiple layers (24) of low-cost organic solid plastic or liquid scintillator, arranged in large arrays of identical scintillator pixels (28). Photodiodes, avalanche photodiodes (30), or solid-state photomultipliers are used to read out the fluorescent pulses from scintillator pixels (28). Multiple scintillator pixels (28) are multiplexed into a few fast digitizers (80) and a few fast FPGA programmable digital microprocessors (78). Selection rule methods are presented for processing multiple near-simultaneous gamma ray collisions within the Compton telescope (28) to identify trackable events that yield gamma ray image data of interest. A calibration method achieves improved energy resolution along with (x,y) position information in pixels (28) made of organic scintillator materials with multiple photodetectors (30).

Abstract: Method and apparatus for minimizing signal noise (20, 22) in thermal, epithermal, and cold neutron fluorescence processes using neutron flux modulation and gamma ray detector pulse gating synchronized to neutron time of flight (NTOF). The apparatus includes a source (12) of thermal, epithermal, and/or cold neutrons, optionally switched between flux or power settings in various embodiments, a gamma ray detector (14) or detection system capable of either being turned ON and OFF, in some embodiments, or else being told to regard or disregard gamma ray signals (20, 22) in other embodiments, a control mechanism (24), and either a target range detector (26) or a prior measurement of target range, in embodiments where the range remains fixed.

Abstract: Apparatus and methods for operating a neutron gamma fluorescence based system by modulating the interrogating neutron flux (?Illumination) to allow for optimized signal-to-noise ratio (SNR) or to improve other detection parameter such as integration time. The apparatus includes one or more sensing systems to detect the range from the neutron source to an Area Under Investigation (AUI) or other parameters, one or more sensing systems to detect the return signal or signals caused by the interrogating neutrons, and a controller to receive inputs from the sensing systems, process them, and generate neutron beam modulation commands capable of being used by an agile neutron source to adjust its flux rate (?Illumination) and/or other characteristics.

Abstract: Apparatus and methods for locating certain substances of interest within remote targets. The detection apparatus includes a neutron beam generator, a pixilated gamma ray detector, data collection modules and sensors, and a detection processing module. If the remote target contains substances of interest, gamma rays radiate isotropically from the remote target when it is bombarded by the neutrons. A portion of these gamma rays are intercepted and detected by a plurality of discrete gamma sensing elements contained in the gamma ray detector, which is spaced apart from the neutron source. The detection processing module determines whether the remote target contains explosive substances and further locates the target by processing the collected data from the gamma ray detector, status information collected from the neutron source, and the position sensor(s) associated with the neutron shield.

Abstract: Apparatus and methods for imaging sources of gamma rays with a large area, comparatively low-cost Compton telescope (20). The Compton telescope (20) uses multiple layers (24) of low-cost organic solid plastic or liquid scintillator, arranged in large arrays of identical scintillator pixels (28). Photodiodes, avalanche photodiodes (30), or solid-state photomultipliers are used to read out the fluorescent pulses from scintillator pixels (28). Multiple scintillator pixels (28) are multiplexed into a few fast digitizers (80) and a few fast FPGA programmable digital microprocessors (78). Selection rule methods are presented for processing multiple near-simultaneous gamma ray collisions within the Compton telescope (28) to identify trackable events that yield gamma ray image data of interest. A calibration method achieves improved energy resolution along with (x,y) position information in pixels (28) made of organic scintillator materials with multiple photodetectors (30).

Abstract: Method and apparatus for minimizing signal noise (20, 22) in thermal, epithermal, and cold neutron fluorescence processes using neutron flux modulation and gamma ray detector pulse gating synchronized to neutron time of flight (NTOF). The apparatus includes a source (12) of thermal, epithermal, and/or cold neutrons, optionally switched between flux or power settings in various embodiments, a gamma ray detector (14) or detection system capable of either being turned ON and OFF, in some embodiments, or else being told to regard or disregard gamma ray signals (20, 22) in other embodiments, a control mechanism (24), and either a target range detector (26) or a prior measurement of target range, in embodiments where the range remains fixed.

Abstract: Apparatus and methods for effectively detecting and locating explosive substances within remote targets, including improvised explosive devices (IEDs). The detection apparatus includes a neutron beam generator, a gamma ray detector, data collection modules and sensors, and a detection processing module. The neutron beam generator includes a fast neutron source, a neutron moderator to slow some or all of the fast neutrons to thermal energies, a partially enclosing neutron shield, and a rotatable neutron shield surrounding the generated neutrons. The neutron shield has an aperture to form a neutron beam directed at a remote target. If the remote target contains explosive substances, gamma rays radiate isotropically from the remote target when it is bombarded by the neutrons. A portion of these gamma rays are intercepted and detected by the gamma ray detector, which is spaced apart from the neutron source.

Abstract: Apparatus and methods for effectively detecting and locating explosive substances within remote targets, including improvised explosive devices (IEDs). The detection apparatus includes a neutron beam generator, a pixilated gamma ray detector, data collection modules and sensors, and a detection processing module. The neutron beam generator includes a fast neutron source, a neutron moderator to slow some or all of the fast neutrons to thermal energies, a partially enclosing neutron shield, and a rotatable neutron shield surrounding the generated neutrons. The neutron shield has an aperture to form a neutron beam directed at a remote target. If the remote target contains explosive substances, gamma rays radiate isotropically from the remote target when it is bombarded by the neutrons. A portion of these gamma rays are intercepted and detected by a plurality of discrete gamma sensing elements contained in the gamma ray detector, which is spaced apart from the neutron source.

Abstract: Apparatus and methods for forming thermal, epithermal, and/or cold neutrons into a beam using momentum transfer. The apparatus includes a source of thermal, epithermal, or cold neutrons, a momentum transfer mechanism containing a collection of suitable atoms that collide elastically with the neutrons, and an apparatus for moving the momentum transfer medium in a preferred direction. The embodiments include locating the neutron source within the test section of a wind tunnel filled with a gas consisting of appropriate atoms, either supersonic, transonic, or subsonic, locating the neutron source in the midst of multiple rotors constructed of appropriate atoms, and locating the neutron source inside a tube constructed of appropriate atoms, where the tube is excited by a mechanical transducer to a bulk acoustic wave, while the neutron source is optionally switched off and on to cause neutrons to enter the tube walls only when the tube walls are moving in the preferred direction.

Abstract: Apparatus and methods for operating a neutron gamma fluorescence based system by modulating the interrogating neutron flux (?Illumination) to allow for optimized signal-to-noise ratio (SNR) or to improve other detection parameter such as integration time. The apparatus includes one or more sensing systems to detect the range from the neutron source to an Area Under Investigation (AUI) or other parameters, one or more sensing systems to detect the return signal or signals caused by the interrogating neutrons, and a controller to receive inputs from the sensing systems, process them, and generate neutron beam modulation commands capable of being used by an agile neutron source to adjust its flux rate (?Illumination) and/or other characteristics.