78 results about "Neutron moderator" patented technology

The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. The detector consists of one or more thin screens embedded in transparent hydrogenous light guides, which also serve as a neutron moderator. The emitted particles interact with the scintillator screen and produce a high light output, which is collected by the light guides into a photomultiplier tube and produces a signal from which the neutrons are counted. Simultaneous gamma-ray detection is provided by replacing the light guide material with a plastic scintillator. The plastic scintillator serves as the gamma-ray detector, moderator and light guide. The neutrons and gamma-ray events are separated employing Pulse-Shape Discrimination (PSD). The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc.

The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. The detector consists of one or more thin screens embedded in transparent hydrogenous light guides, which also serve as a neutron moderator. The emitted particles interact with the scintillator screen and produce a high light output, which is collected by the light guides into a photomultiplier tube and produces a signal from which the neutrons are counted. Simultaneous gamma-ray detection is provided by replacing the light guide material with a plastic scintillator. The plastic scintillator serves as the gamma-ray detector, moderator and light guide. The neutrons and gamma-ray events are separated employing Pulse-Shape Discrimination (PSD). The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc.

The invention relates to an epoxy resin based neutron and gamma ray shielding composite material, as well as a preparation method and an application thereof, belonging to the technical field of shielding materials, used for solving the following technical problems that the shielding property of a shielding material in the prior art is difficultly combined with other physical and mechanical properties; requirements of application flexibility and construction diversity cannot be satisfied; and furthermore, the preparation process is complex. The epoxy resin based neutron and gamma ray shielding composite material is composed of the following components in parts by weight: 5-15 parts of epoxy resin, 2-9 parts of a curing agent, 1-10 parts of a fast neutron moderator, 2-20 parts of a thermal neutron absorber, 65-85 parts of a gamma ray shielding agent, 0-3 parts of an inert diluent, 0-3 parts of an active diluent, 0-2 parts of an accelerant, and 0.5-5 parts of auxiliaries. The epoxy resin based neutron and gamma ray shielding composite material has excellent neutron and gamma ray mixing-field shielding property; furthermore, the epoxy resin based neutron and gamma ray shielding composite material is low in toxicity, free from smell, simple in preparation process and convenient to construct; and thus, the epoxy resin based neutron and gamma ray shielding composite material can be widely applied in various fields of strict radiation-resistant requirements.

A well logging instrument includes a source of high energy neutrons arranged to bombard a formation surrounding the instrument. A scintillator sensitive to gamma radiation resulting from interaction of the high energy neutrons with the formation is disposed in the instrument. A neutron shielding material surrounds the scintillator. A neutron moderator surrounds the neutron shielding material. An amplifier is optically coupled to the scintillator.

A reactivity control rod adapted to be used in a reactor core of a fast reactor and disposed at a substantially central portion of the reactor core for controlling a reactivity therein. The reactivity control rod includes a wrapper tube surrounded by a plurality of fuel rods in a reactor core, and a plurality of neutron absorber rods arranged in the wrapper tube. At least one of the plurality of neutron absorber rods includes a cladding tube and a mixture filled in the cladding tube. The mixture is composed of a neutron absorber that absorbs a neutron and a neutron moderator that moderates the neutron.

A fluoride sintered body suitable for a moderator which moderates high-energy neutrons so as to generate neutrons for medical care with which an affected part of the deep part of the body is irradiated to make a tumor extinct comprises MgF 2 of a compact polycrystalline structure having a bulk density of 2.90g / cm 3 or more and as regards mechanical strengths, a bending strength of 10MPa or more and a Vickers hardness of 71 or more.

A neutron detection system comprising a radiation portal monitor is disclosed. The radiation portal monitor includes a neutron moderator sheet and a neutron-sensing panel and is configured to receive incoming neutrons through a neutron collection portal area. The neutron-sensing panel comprises a neutron-sensing material optically coupled to a plurality of optical fibers such that the neutron moderator sheet and the neutron-sensing panel are disposed substantially parallel to the neutron collection portal area.

The invention provides a quick dry type neutron-shielding lacquer putty and a method for preparing the same. The quick dry type neutron-shielding lacquer putty is used for filling a hole or an aperture of a neutron radiant point shielding structure in order to reduce the leakage of neutron radiation and improve the whole protective performance of a shielding system. The material is prepared by adopting a coagulant, a neutron moderator, a neutron absorber, a colorant, water and other compositions mixed together. The quick dry type neutron-shielding lacquer putty has good neutron-shielding performance, short drying time, simple structure, convenient construction, strong practicability and good economical benefit.

In a neutron moderator, a neutron irradiation method, and a hazardous substance detection apparatus, an inspection chamber (21) where an inspection target (A) can be inserted and removed is provided. Around this inspection chamber (21), a thermal neutron absorbing material (15) is provided. A neutron generator(11) is arranged facing the inspection target (A) in the inspection chamber (21), and a neutron moderating material (12) is arranged at an opposing side of the inspection target (A) with respect to the neutron generator (11). The external surface of the neutron moderating material (12) is covered with gamma ray shielding materials (13, 14), and a Ge detector (24) and a BGO detector (25) are provided to detect gamma ray emitted from the inspection target (A). With this configuration, necessary fast neutron and thermal neutron can be taken out, while suppressing generated secondary gamma ray. Accordingly, a hazardous substance can be detected accurately regardless of a constituent element thereof.

The present invention discloses a water injection and drainage full-automatic multisphere neutron spectrometer and a measurement method. A system comprises a water injection and drainage system, multiple layers of annular lead glass spherical shells, a spherical neutron detector and an analyzing and processing system. According to a neutron measurement place, the water injection and drainage full-automatic multisphere neutron spectrometer is installed, at measurement, the water injection and drainage system injects the water in the multiple layers of annular lead glass spherical shells orderly, thereby achieving the purpose of changing the thickness of a neutron moderator, and measuring the neutrons of different energy in an environment. According to the present invention, the water injection and drainage system carries out the full-automatic control on the different parameters of a single spherical detector, thereby achieving the multisphere detection purpose, solving the manufacturing complexity of a plurality of detection systems in a conventional multisphere system, reducing the manufacturing cost, at the same time, effectively avoiding the problems that the detectors in the conventional multisphere system influence each other and are inconsistent, and the overall carrying of the plurality of detectors is tedious.

The invention aims to disclose a radioactive monitoring system for pedestrians and baggage, comprising a radioactive security inspection device for monitoring radioactivity, and a remote monitoring and controlling platform for monitoring the radioactive security inspection device, display measurement results, statistically analyzing data and controlling the system; the radioactive security inspection device is in a communication connection with the remote monitoring and controlling platform; the radioactive security inspection device is internally provided with a gamma detector, a neutron detector and an electronics system; and the external side of the neutron detector is coated with a neutron moderator; the radioactive security inspection device is further provided with a display, an alarming lamp and an occupancy sensor. Compared with the prior art, the radioactive monitoring system for pedestrians and baggage sensitively responds to neutron rays and gamma rays; the neutron detector and the gamma detector are relatively small in volume and the whole volume of the instrument is small, so that the cost of installation and transportation is lower; and the radioactive monitoring system for pedestrians and baggage is applicable to security inspection in entrances of important places to realize the purpose of the invention.

The invention discloses an epoxy resin based neutron-shielding composite material and a preparation method thereof, belongs to the technical field of shielding materials and solves the technical problems that the shielding property and other physical and mechanical properties of a shielding material in the prior art are hard to satisfy simultaneously, the requirements for application flexibility and construction diversity cannot be met and the preparation process is complex. The composite material comprises the following components in parts by weight: 15-50 parts of epoxy resin, 7-30 parts of a curing agent, 5-40 parts of a fast neutron moderator, 5-55 parts of a thermal neutron absorbing agent, 0-10 parts of an inert diluent, 0-10 parts of an active diluent, 0-5 parts of an accelerant and 0.2-4.0 parts of an additive. The composite material has excellent neutron-shielding performance, has low toxicity, is odorless, is simple in preparation process and convenient in construction, and can be widely applied to various fields where radiation protection is strictly demanded.

An instrument for performing measurements downhole, includes: a neutron source; and a neutron moderating material exhibiting high compressive strength and high performance for moderation and shielding of neutrons, the shielding disposed proximate to the neutron source. A method for fabricating the instrument is provided.

A system for medical imaging is provided and includes at least one neutron generator having a neutron generator fuel material and at least one neutron moderator material, a gantry for stationing an imaging subject, a neutron collimator attached to the neutron generator, the collimator disposed between the neutron moderator and the imaging subject, at least one gamma ray camera electrically connected to a processor-based data acquisition system, and software executing on the processor-based data acquisition system from a non-transitory physical medium, the software providing a first function for producing at least one gamma ray spectrum or image, a second function for applying correction factors to the gamma ray spectra or images, and a third function for analyzing the corrected gamma ray spectra or images to process one or more clinically relevant images of one or more targeted or general areas of the imaging subject.

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. 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.

The invention relates to a portable passive nuclear power reactor, and belongs to the technical field of reactors. The portable passive nuclear power reactor comprises a shell, a neutron reflecting layer, a thermoelectric converter, a hydrogen inlet valve, a hydrogen regulator, fuel, a hydrogen conduction pipe, a heat pipe group and a current output terminal, wherein the shell defines a cylinder structure with an accommodating chamber; the accommodating chamber is divided into a hydrogen regulation chamber and a fuel chamber by the neutron reflecting layer; the thermoelectric converter is positioned on the upper part of the fuel chamber; the hydrogen inlet valve is positioned on the top of the shell; the hydrogen regulator is positioned in the hydrogen regulation chamber; the fuel is positioned in the fuel chamber; the hydrogen regulation chamber is communicated with the fuel chamber by the hydrogen conduction pipe; the heat pipe group is communicated with the thermoelectric converter and the fuel; the current output terminal is positioned outside the accommodating chamber, and penetrates through the shell to be communicated with the thermoelectric converter. According to the reactor disclosed by the invention, by utilizing the characteristic that hydrogenation and dehydrogenation performance of metal uranium can be changed along with the temperature, the design of the passive reactor utilizing the hydrogen as a neutron moderator and an operation control agent is realized.

There are provided a method for manufacturing a magnesium fluoride sintered compact to be free from cracks and chipping and to have high relative density, a method for manufacturing a neutron moderator, and the neutron moderator. The method for manufacturing a magnesium fluoride sintered compact includes a powder filling process for filling a magnesium fluoride powder material into a die by tapping, and an intermediate body sintering (pulsed electric current sintering) process for performing pulsed electric current sintering for sintering the filled magnesium fluoride powder material while applying a pulsed electric current thereto, to obtain a magnesium fluoride sintered compact (intermediate body).

The invention discloses a neutron shielding composite material and a preparation method thereof and belongs to the field of nuclear radiation shielding materials. The method is simple in technology and high in finished-product rate; the prepared foam ceramic-based neutron shielding composite material has excellent neutron shielding performance, small volume density and strong corrosion-resisting performance. The preparation method comprises the following steps: preparing net-shaped foam ceramic with certain mechanical properties through a polyurethane precursor method; then pre-treating a foamceramic material; after uniformly mixing 60 to 90 parts of a neutron-moderator material by mass, 10 to 40 parts of a neutron absorber material by mass and 0 to 10 parts of an additive by mass, whichare uniformly melted, putting a mixture into the pre-treated foam ceramic material; carrying out negative-pressure immersion at temperature higher than the melting temperature of the moderator material, so as to fill one part of the melted high-polymer moderator material into hollow hole ribs remained by polyurethane ignition loss; meanwhile, filling gaps of the foam ceramic; after cooling, removing a surplus high-polymer material which is overflowed from a matrix part, so as to prepare the novel neutron shielding foam ceramic composite material.

The invention discloses a thermal neutron transmission imaging method and imaging device based on a compact D-D neutron source. The compact D-D neutron source is adopted to provide exogenous neutrons;2.45 MeV D-D fast neutrons outputted by the D-D neutron source are moderated into thermal neutrons or epithermal neutrons through the neutron moderator; after being slowed down, the neutrons enter abig-end-up conical neutron collimation hole channel vertically formed in a neutron slowdown body above a D-D neutron source; the collimated thermal neutron beam transmits a detected object; thermal neutrons penetrating through an object in a transmission mode are detected through the thermal neutron image detector system installed at the upper end of the conical neutron collimation hole channel, the thermal neutrons are converted into digital transmission images through the thermal neutron image detector system, two-dimensional spatial distribution of thermal neutron transmission intensity isobtained, and then the internal structure of the detected object and the spatial distribution situation of different materials are obtained. The method has the characteristics of mobility, rapidness,accuracy, no damage and good spatial resolution, and can be used for nondestructive detection of objects.

According to an aspect, a magnesium fluoride sintered compact includes a disc-shaped magnesium fluoride sintered compact having a through hole passing through a center axis of the disc-shaped magnesium fluoride sintered compact. The magnesium fluoride sintered compact has a relative density of 95% or higher.

A method of manufacturing p-n junction in semiconductor material such that small dimensions of such junctions are maintained, and associated lattice dislocations of such junctions may be preferentially maintained, and devices with such patterned semiconductor material, is disclosed. Typically, a neutron moderator is used to slow fast neutrons to thermal energies. A mask made from thermal neutron absorbing material, such as cadmium, is placed in close proximity to such neutron moderator. Thermal neutron focusing optics, such as compound refractive lenses, are used to collect and focus thermal neutrons emitted from the mask such that the pattern or portion of the pattern is transferred to the silicon body, with neutrons transmitted from the window areas in the mask and through the neutron optic so as to form the donor dopant concentration for the n-type regions by transmutation of silicon atoms into phosphorus. An electronic device produced by such a method has vertical p-n junctions continuous between both major surfaces and horizontal alternating p-type and n-type regions across most of the face of the material, such that unique properties are achieved.

The invention discloses a portable energy adjusting device for equivalent dose detection of a heat energy-100 MeV neutron, which comprises an inelastic scatterer, a fast neutron moderator, an energy adjustor and a thermal neutron detector. The whole device takes the shape of a ball, the thermal neutron detector is arranged at the center of a ball body and coated with the spherical fast neutron moderator; the fast neutron moderator is coated with a spherical ultrafast neutron inelastic scatterer; and the energy reaction adjustor is positioned between the fast neutron moderator and the fast neutron inelastic scatterer. The portable energy adjusting device has the advantages of compact structure and light weight and can improve the reaction of a high-energy neutron by about 30 percent as well as the sensitivity of the neutron by about 18-40 times through experimental evidence compared with the prior art.

A nuclear fuel composition includes a transuranic fuel and a neutron moderator mixed with transuranic fuel. The neutron moderator includes at least one of hafnium or zirconium.

A fluoride sintered body suitable for a moderator which moderates high-energy neutrons so as to generate neutrons for medical care with which an affected part of the deep part of the body is irradiated to make a tumor extinct comprises MgF2 of a compact polycrystalline structure having a bulk density of 2.90 g / cm3 or more and as regards mechanical strengths, a bending strength of 10 MPa or more and a Vickers hardness of 71 or more.

The systems for determining and imaging wax deposition and simultaneous corrosion and wax deposit determination in pipelines relate to systems for determining wax deposition and corrosion by one or both of two techniques. In both techniques, a source of neutron radiation is directed at the pipeline. In one technique, a neutron detector surrounded by an absorption shield defining a collimation window counts neutrons reflected back to the detector by back diffusion or backscatter radiation. In the other technique, a gamma ray detector measures gamma rays emitted when the emitted neutrons are absorbed in the pipeline. A neutron moderator-reflector is placed around three sides of the pipeline to increase the likelihood of neutron capture.