Disclosed is a directional gamma ray or neutron detector system that locates a radioactive source both horizontally and vertically. In some embodiments, the system comprises four side detectors arrayed around a detector axis, and an orthogonal front detector mounted frontward of the side detectors. Embodiments can calculate the azimuthal angle of the source based on the detection rates of the side detectors, while the polar angle of the source may be calculated from the front detector rate using a predetermined angular correlation function, thereby localizing the source from a single data set without iterative rotations. In applications such as hand-held survey meters, walk-through portals, vehicle cargo inspection stations, and mobile area scanners, embodiments enable rapid detection and precise localization of clandestine nuclear and radiological weapons.

An apparatus and method are described which enable real time measurements to measure the margin to criticality in a process for manufacturing fissile materials. An exemplary apparatus includes a neutron source capable of being modulated, an optional moderator to reduce the thermal energy of neutrons from the neutron source, a collimator for controlling the direction of any neutrons emanating in use from the target, a plurality of detector arrays positioned in predetermined locations relative to a process vessel for detecting process variables and for sending signals representative of the process variables in real time to a processor for receiving the signals and converting the detected process variables into margin to criticality measurements.

A system and method is disclosed for detecting fissionable materials. In one embodiment the system may incorporate a neutron pulse generator configured to generate multiple short pulses of neutrons, or a single pulse of sufficient intensity, in a vicinity of an object of interest. The source pulse of neutrons includes neutrons which each have a full width half maximum time duration of less than about 100 ns and a peak energy level no greater than about 20 MeV. A fast response detector is used which is able to detect single neutron events indicative of fission neutrons having been produced by the source pulse of neutrons interacting with fissionable material associated with the object of interest, and which arrive at the fast response detector within a predetermined time window immediately before arrival of the source neutron pulses.

A device providing high-accuracy, high-speed detection of fissile materials, the device comprising two coaxially arranged cylinders: an inner cylinder made of lead, which acts as a gamma shield and as a neutron multiplier; and an outer cylinder made of polyethylene, which acts as a neutron thermalizer. A pedestal capable of vertical axial movement is disposed in the lower part of the inner cylinder. Fifteen helium-3 counters with cadmium filters can be built into the wall of the outer cylinder in a circle, parallel to the generatrix. An isotropic deuterium-tritium 14 MeV neutron generator can be mounted in the wall of the outer cylinder, perpendicular to the generatrix. In one aspect, before installation, a vessel and a structural material contained therein are subjected to gamma scanning. Then, using the movable pedestal, the vessel is mounted in the inner cylinder so the center of mass of the structural material is opposite detectors.

Disclosed is a directional gamma ray or neutron detector system that locates a radioactive source both horizontally and vertically. In some embodiments, the system comprises four side detectors arrayed around a detector axis, and an orthogonal front detector mounted frontward of the side detectors. Embodiments can calculate the azimuthal angle of the source based on the detection rates of the side detectors, while the polar angle of the source may be calculated from the front detector rate using a predetermined angular correlation function, thereby localizing the source from a single data set without iterative rotations. In applications such as hand-held survey meters, walk-through portals, vehicle cargo inspection stations, and mobile area scanners, embodiments enable rapid detection and precise localization of clandestine nuclear and radiological weapons.

Disclosed herein are a method, apparatus, and software for passive, non-destructive assay of holdup deposits in nuclear piping by in-pipe apparatus. A detector deployed within a pipe is collimated to observe radiation impinging radially inward from decay of deposits that lie on the pipe wall. A radiation detector is centered in the pipe and collimated by a pair of coaxial shielding discs disposed equidistant from the detector. This arrangement causes radiation from a truncated cylinder of pipe deposit within a field of regard to impinge on the detector, while precluding radiation emanating from pipe walls beyond the field of regard from reaching the detector. Hence, observations are unique to a known cylindrical length of pipe. The detector assembly is translated through pipes by an autonomous mobile robotic apparatus. Computer software controls the robotic apparatus, logs data, and post-processes to assay deposits.

Methods and systems that utilize centrifugally tensioned metastable fluid detector (CTMFD) sensors and an external probing source to detect the presence of fissile and fissionable materials, including but not limited to special nuclear materials (SNMs), in containers. Such a method includes subjecting a container to probing with a fission-inducing radiation species that induces fission in an fissile or fissionable material, detecting fission neutrons emitted from the fissile or fissionable material with CTMFD sensors that each contain a detection fluid in which the fission neutrons induce cavitation in a centrifugally tensioned portion of the detection fluid. A threshold energy neutron analysis mode is then utilized to reject the radiation species and detect a fraction of the fission neutrons that have energies above a predetermined energy threshold determined by centrifugally-induced tension in the centrifugally tensioned portion of the detection fluid within each of the CTMFD sensors.

An apparatus and method are described which enable real time measurements to measure the margin to criticality in a process for manufacturing fissile materials. An exemplary apparatus includes a neutron source capable of being modulated, an optional moderator to reduce the thermal energy of neutrons from the neutron source, a collimator for controlling the direction of any neutrons emanating in use from the target, a plurality of detector arrays positioned in predetermined locations relative to a process vessel for detecting process variables and for sending signals representative of the process variables in real time to a processor for receiving the signals and converting the detected process variables into margin to criticality measurements.

Systems, devices and methods for inspecting and imaging of contents of a volume is disclosed. One implementation of the disclosed systems, devices and methods includes an apparatus for inspecting and imaging of contents of a volume of interest which includes a first particle tracking unit of detectors to receive incoming charged particles that transit through an object and to measure position and direction of the charged particles that transit through the object while allowing the charged particles to pass through, and a second particle tracking unit of detectors installed relative to the first particle tracking unit of detectors and to the volume of interest containing the object of inspection so that it is positioned to receive the outgoing charged particles that transit through the first particle tracking unit and transit through the object of inspection and to measure a position and a direction of the outgoing charged particles. The apparatus also includes a processor that processes information from the first and second particle tracking units of detectors to yield an estimate of a spatial map of atomic number and a density of the object. The methods disclosed here include triggering algorithms for signal selection, positional calibration algorithms for locating particle tracking units in absolute three dimensional coordinate space, and three-dimensional tomographic image reconstruction algorithms combining the tracking information from multiple pairs of particle tracking units.

A gamma-ray spectrum classification apparatus, comprising circuitry configured: to provide a denoising autoencoder to receive gamma-ray spectrum data representing a gamma-ray spectrum of a material to be classified and to determine feature data indicative of one or more features representative of the gamma-ray spectrum data; and to provide a classification neural network to receive the feature data and to classify the material to be classified as one of a plurality of predetermined classifications using the feature data.