75 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.

An apparatus for generating medical isotopes provides an annular fissile solution vessel surrounding a neutron generator. The annular fissile solution vessel provides for good capture of the emitted neutrons and a geometry that provides enhanced stability in an aqueous reactor. A neutron multiplier and/or a neutron moderator may be used to improve the efficiency and control the criticality of the reaction in the annular fissile solution vessel.

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 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 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.

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.

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.

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.

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 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.

A monitor of fusion neutron flux is formed by three fission chamber detectors set in stainless steel shell. It is featured as coating different mass of high purified fission material on cathodes of two fission chamber detectors make their sensitivity be 1: 100, setting the third fission chamber detector to be blank detector with no fission material, setting a layer of Cd-heat neutron shielding layer with neutron moderator structure in shell, setting lead shielding layer in neutron moderator structure and placing three fission chamber detectors in lead shielding layer.