45 results about "Special nuclear material" patented technology

A method and associated apparatus for detecting concealed fissile, fissionable or special nuclear material in an article, such as a shipping container, is provided. The article is irradiated with a source of fast neutrons, and fast neutrons released by the fissile or fissionable material, if present, are detected between source neutron pulses. The method uses a neutron detector that can detect and discriminate fast neutrons in the presence of thermal neutrons and gamma radiation. The detector is able to process high count rates and is resistant to radiation damage, and is preferably a solid state neutron detector comprised of silicon carbide.

A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to ³He-based detectors without requiring ³He and without containing toxic, flammable, or high-pressure materials.

A backpack laser-induced breakdown spectroscopy LIBS system to provide rapid in-field elemental analysis of environmental samples important to the safeguarding of special nuclear materials.

A system for detecting substances, the system including a dual-energy radiography (DER) system including a gamma-ray radiation source, including a beam accelerator and a target to which the accelerator sends a beam thereby producing gamma rays, and a plurality of gamma ray detectors positioned to detect gamma rays that pass from the gamma-ray radiation source through an object to be inspected, wherein the DER system is adapted to indicate a presence of a high-Z substance, by detecting a difference in a transmission attenuation characteristic of the high-Z substance as opposed to low-Z and medium-Z substances and differentiating among high-Z substances according to their density, as determined from a plurality of radiographic views.

A method and apparatus for generating high-energy beams of electrons or x-rays through laser wakefield acceleration to remotely examine containers is disclosed. By scanning the beam of electrons or x-rays across a container, an inspector can remotely determine whether the containers contain items of interest, such as special nuclear materials, without having to manually inspect the contents of the container. The invention can be compact enough to be portable, which provides for the flexibility to examine a variety of different containers under a variety of different conditions.

The rare earth metal Lutetium in compound form is used in check sources of various shapes and sizes to calibrate and tune radiation detection devices. Radioactive Lutetium-176, a naturally occurring (non man-made) isotope forming part of the Lutetium compound, produces gamma energies of approximately 90, 200, and 300 kilo-electron Volts which are used in the calibration. Such gamma energies are close to the predominant spectral lines of special nuclear materials such as U-235 and Pu-239, which is to be monitored by radiation detection devices. Lutetium in a radioactive calibration source (which is either integrated into the radiation detection device or positioned close to it during calibration) provides benefits including that no reactor or accelerator is required during production or use, for the creation of man-made radioactivity, no dangerous radiation exposure occurs and (because of the long half-life of Lu- 176) the radioactive calibration source essentially never needs to be replaced. Moreover, the handling of such a source is much less restrictive and costly than that of a conventional man-made radioactive isotope.

System and method for XRD-based false alarm resolution in computed tomography (“CT”) threat detection systems. Following a scan of an object with a megavoltage CT-based threat detection system, a suspicious area in the object is identified. The three dimensional position of the suspicious area is used to determine a ray path for the XRD-based threat detection system that provides minimal X-ray attenuation. The object is then positioned for XRD scanning of the suspicious area along this determined ray path. The XRD-based threat detection system is configured to detect high density metals (“HDMs) as well as shielded Special Nuclear Materials (“SNMs”) based on cubic or non-cubic diffraction profiles.

The invention uses a series of combined passive neutron and gamma ray sensors systematically placed along a path of commercial traffic, for example an airport runway, combined with a pulsed source of low energy protons and deuterons. The pulsed source produces monoenergetic gamma rays and low energy (60 keV) neutrons. This pulsed source uses a pinch-reflex ion diode operated on a pulsed power generator to produce proton beams. These beams bombard a PTFE (Teflon) target to produce characteristic gamma-rays. These gamma rays would induce a fission reaction in any fissile material creating gamma rays and neutrons. The passive sensors located in the path of commercial traffic would sense both the resultant gamma and neutron products of the reaction. The short interrogation pulse, approximately 50 nanoseconds, provides a timing marker which can be used to turn on the passive detectors after the interrogation pulse so as to avoid saturation and to enable measuring the spectrum of the fast neutrons using time of flight. The decay rate of the intensity of fast and slow (thermalized by interaction with the runway materials) neutrons provides an unambiguous signature of the presence of fissile material.

A method and system for detecting special nuclear materials are disclosed. Said method and system detect the special nuclear materials by making use of the photofission characteristic and thermal neutron induced fission characteristic thereof. In one preferred embodiment, the high density and/or high atomic number region in the object to be detected is also detected first as a suspicious region.

The invention discloses a method for quickly recognizing a heavy nuclear material by using cosmic ray muons and solves the problems of long judgment time and low accuracy in judging whether special nuclear materials are hidden in containers or other containers in ports, airport security check and other nuclear proliferation prevention application scenes in the prior art. The method comprises the steps as follows: firstly, constructing a cosmic ray muon detection system model, and calculating the scattering angle root mean square value theta i sequence of 10<6> muons penetrating through commonhigh, middle and low atomic number material targets; then, calculating the scattering angle root mean square value theta x, measured by the detection system in a short time, of the muons penetrating through targets; calculating the grey correlation degree of theta x and each value in the theta i sequence, and determining one target as the heavy nucleus material when the grey correlation degree isthe highest. The method is ingenious in design, easy to implement and capable of quickly and accurately judging whether special nuclear materials are hidden in closed containers and is very suitable for detecting whether heavy nuclear materials are hidden in cargos in containers or other containers in custom wharfs and airports.

Embodiments relate to an advanced fast and thermal neutron detector material composition with the properties useful for Special Nuclear Material (SNM) detection. Specific embodiments of the material composition result in two excimer scintillation light production mechanisms that provide two corresponding independent techniques for gamma discrimination; namely Pulse Shape Discrimination and Pulse Height Discrimination. A dual discrimination method, Pulse Shape and Pulse Height Discrimination (PSHD), can be implemented relying on both pulse height discrimination and pulse shape discrimination, and can allow the operation of large area, fast and thermal neutron detectors.

A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little α-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.