561 results about "Neutron source" patented technology

The invention provides a beam shaper for neutron-capture therapy in order to improve flux and quality of a neutron source. The beam shaper comprises a target, a slowing body adjacent to the target, a reflector wrapping the slowing body, a thermal neutron absorber adjacent to the slow body, a radiation shield arranged in the beam shaper and a beam outlet. The target generates nuclear reaction with a proton beam incident from a beam inlet so as to generate neutrons, the neutrons form a neutron beam which defines a main axis, the slowing body slows down the neutrons generated from the target to an epithermal neutron energy region, the reflector guides the neutrons deviating from the main axis to the main axis so as to improve intensity of the epithermal neutron beam, a gap passage is arranged between the slowing body and the reflector so as to improve epithermal neutron flux, the thermal neutron absorber is used for absorbing the thermal neutron so as to avoid causing overmuch dosed with shallow normal tissue during therapy, and the radiation shield is used for shielding leaked neutrons and photon so as to reduce normal tissue dose in a non-radiation region.

Provided are methods and devices for compression of a spheromak plasma (e.g., deuterium-trirtium (D-T)-derived) in a magnetic well configured within a plasma combustion chamber using an induction coil axially adjacent to the plasma, wherein a moveable member (e.g., piston, cam and follower) drives the induction coil toward the plasma, pushing the plasma via magnetic pressure into the magnetic well and compressing the plasma substantially adiabatically (e.g., coil motion is well below the plasma sound speed). The compression quickly increases both plasma density and temperature past the point of ignition, and after plasma burn, the coil is backed-off to allow the plasma to re-expand, providing for refueling and repetition of the compression cycle. Additionally provided are spaced annular plasma formation electrodes, suitably configured for generating and injecting magnetized plasma into a plasma combustion chamber. Preferably, spaced annular plasma formation electrodes are used in combination with moveable compression members as disclosed herein.

A tool for measuring formation properties in situ. The tool includes a solid state neutron detector and a neutron source disposed on a drill string or wireline. The detector includes a boron carbon surface deposited on a substrate, and the surface can be multi-planar or curved for allowing sensitivity in more than one direction.

In order to improve the flux and the quality of a neutron source, the invention provides a beam shaping body for neutron capture therapy. The beam shaping body comprises a beam inlet, a target, a retarding body adjacent to the target, a reflecting body surrounding the external of the retarding body, a thermal neutron absorber adjacent to the retarding body, and a radiation shield and a beam outlet formed in the beam shaping body, wherein the target has nuclear reaction with proton beam entering from the beam inlet, so as to produce a neutron; the neutron forms a neutron beam; the neutron beam defines a main axis; the retarding body slows down the neutron produced by the target to an epithermal neutron energy region; the retarding body is designed to a shape containing at least one cone; the reflecting body guides the neutron deviated from the main axis back to the main axis, so as to improve the strength of an epithermal neutron beam; the thermal neutron absorber is used for absorbing a thermal neutron, so as to prevent the thermal neutron from causing excessive dosage with a superficial normal tissue during therapy; the radiation shield is used for shielding leaked neutron and photon, so as to reduce the normal tissue dosage of a non-irradiated region.

A tool for formation logging includes a support configured for movement in a borehole; a neutron source disposed on the support; a neutron monitor disposed on the support and configured to monitor an output of the neutron source; a gamma-ray detector disposed on the support and spaced apart from the neutron source; and a shielding material disposed between the gamma-ray detector and the neutron source.

Method for evaluating cement integrity in a cased well environment using a logging tool that has a neutron source and one or more neutron or gamma ray detectors. Neutron porosity logs are obtained from the well before (42) and after (41) casing. This log data along with well dimensions and material composition parameters are the input quantities to a multi-parameter database (43) that is constructed by computer modeling or laboratory experiments to relate volume fraction for fluid filled channels in the cement sheath to the input quantities. The channel volume fraction (45) corresponding to the input quantities is identified or interpolated (44) from the multi-parameter database.

A process to safely convert about 95% of the nuclear waste into a usable fuel source is disclosed. The process, involving a sub-critical power reactor and a proliferation-resistant fuel cycle, consumes depleted uranium or thorium fuel with fissionable fuel, including reactor or weapons-grade plutonium. The reactor is comprised of coaxial neutron and energy-amplifying regions separated by moderating and thermal neutron absorbing layers. Control of the water or gas-cooled reactor is provided by plutonium-helium loops with a variable volume flow rate and an external source of neutrons that quickly reacts to any fluctuations of the reactor parameters. A second embodiment of the invention is a compact sub-critical propulsion reactor utilizing fission electric cell and thermo-acoustic technology for electrical power generation.

A method for inferring the photoelectric absorption of a formation by directly mapping spectroscopic measurements of gamma rays induced in the formation using a fast neutron source. The mapping is accomplished by creating a polynomial function based on counts of gamma-ray events in the gamma-ray energy spectrum; the coefficients of the polynomial function are determined in known calibration environments, and the value of the polynomial is the inferred photoelectric absorption parameter. The spectroscopic measurements are preferably generated by sorting gamma-ray counts of the gamma-ray spectrum into a plurality of energy-dependent channels, and measuring these gamma-ray energy distributions during different portions of the firing cycle where different types of dominant gamma-ray production reactions occur.

A logging tool includes an elongated body housing a neutron source and at least one neutron detector positioned along one side of the neutron source. Some embodiments of the logging tool include at least one gamma ray detector longitudinally separated from and to one end of the neutron source, and may be used to make simultaneous gamma ray and neutron logging measurements. In some embodiments, the logging tool also includes a (n, 2n)-neutron shield positioned to one end of the neutron detector, longitudinally between the neutron detector and the neutron source.

A method for formation logging includes acquiring measurements of neutron-induced signals having azimuthal information using a neutron tool; processing the measurements into a plurality of azimuthal sector data for each acquisition interval; and deriving a selected parameter from the plurality of azimuthal sector data. A logging tool includes a housing adapted to move in a borehole; a circuitry having memories for storing neutron-induced measurements; a neutron source disposed in the housing; and at least one detector bank disposed in the housing spaced apart from the neutron source, wherein each of the at least one detector bank comprises at least one detector disposed around a periphery of the housing such that the at least one detector is more sensitive to signals from an azimuthal direction, and wherein count rates detected by each of the at least one detector are separately stored in the memories.

The invention relates to a multi-parameter logging method while drilling based on a controllable neutron source, which includes the steps of utilizing a multi-detector measuring system consisting of the D-T controllable neutron source, two thermal neutrons and two gamma detectors, sufficiently utilizing fast neutrons transmitted by the controllable neutron source to militate with atomic nucleuses of formation elements by means of special pulse and measuring timing sequence design, recording gamma energy spectrums, gamma time spectrums and thermal neutron time spectrums at different positions, and performing simultaneous measurement of multiple parameters such as formation density, formation porosity, formation fluid saturation, formation element content and the like with a nuclear logging instrument in a drilling process by means of different spectral resolution and data processing, so that valuation on formation lithology, formation porosity and formation fluid saturation while drilling are realized, the same parameter of the formation porosity and the formation fluid saturation can be measured by various methods, logging interpretation ambiguity is decreased, and accuracy and reliability of logging data interpretation are enhanced.

A light water reactor to safely convert depleted uranium into a fuel source that could be used as a sustainable source of energy for centuries. The reactor is a type of breed-burn reactor uniquely combined with a proliferation-resistant fuel cycle with no uranium enrichment and no plutonium isolation. It is comprised of a compact factory-produced fast region and a thermal region that produces about 95% of the core power and contains the passageways for transports of delayed-neutron emitters to the fast region, where they can provide additional neutrons (source-based mode) or all the necessary excitation without an external neutron source (self-regulating mode). A second embodiment of the invention is a small unit driven by a neutron source with beam recycling for propulsion, electrical power or radioisotope production. It could also serve as a demonstration facility for the transmutation reactor with fission-fusion fuel.

A neutron imaging apparatus for obtaining an image of the general shape of a neutron emitting source and a bearing of the source relative to the apparatus, the apparatus comprising a chamber comprising a gas with a high probability of interacting with low energy neutrons, releasing collision products that maintain the neutron momentum, and generating ionization particles. The chamber comprises an electrode for providing an electronic signal indicative of the impact location of ionization particles on the electrode and a field to drift the ionization particles to the electrode. A readout indicates the location and time of impact of each ionization particle on the electrode; a memory stores a plurality of the electronic signals; and a computer receives and analyzes the signals and impact times and indicates the location of the source of neutrons by using back projection algorithms to calculate three-dimensional vectors indicative of the neutron path directions.

A therapy apparatus for producing thermal neutrons at a tumor site in a patient has a plurality of fast neutron sources surrounding a moderator, a fast neutron reflecting media around the fast neutron sources, a gamma-ray and neutron shielding media surrounding the fast neutron reflecting media, and a patient chamber positioned inside the moderator. The fast neutron sources are positioned around the moderator to maximize and direct the neutron flux to said tumor site.

The invention concerns radiographic equipment. The equipment includes a source of substantially mono-energetic fast neutrons produced via the deuterium-tritium or deuterium-deuterium fusion reactions, comprising a sealed-tube or similar generator for producing the neutrons. The equipment further includes a source of X-rays or gamma-rays of sufficient energy to substantially penetrate an object to be imaged and a collimating block surrounding the neutron and gamma-ray sources, apart from the provision of one or more slots emitting substantially fan-shaped radiation beams. Further included is a detector array comprising a multiplicity of individual scintillator pixels to receive radiation energy from the sources and convert the received energy into light pulses, the detector array aligned with the fan-shaped beams emitted from the source collimator and collimated to substantially prevent radiation other than that directly transmitted from the sources reaching the array. Conversion means are included for converting the light pulses produced in the scintillators into electrical signals. Conveying means are included for conveying an object between the sources and the detector array. Computing means are included for determining from the electrical signals the attenuation of the neutrons and the X-ray or gamma-ray beams and to generate output representing the mass distribution and composition of the object interposed between the source and detector array. The equipment further includes a display means for displaying images based on the mass distribution and the composition of the object being scanned.

The invention discloses a small neutron source adopting a windowless gas target, which belongs to the field of nuclear technology and application. In the invention, an ECR (Electron Cyclotron Resonance) ion source is used for generating a deuterium ion and directly extracted by a high-voltage extraction electrode for bombarding a windowless gas target sealed by a plasma; because the windowless deuterium gas target is sealed by adopting the plasma, the windowless deuterium gas target is allowed to bear high-flow-strength beam current; and because the energy loss of the deuterium ion when penetrating through a plasma window is less, the neutron yield is higher. Compared with a neutron pipe, the neutron source provided by the invention has high allowed beam current strength and high neutron yield. Compared with an accelerator neutron source with large size, complex system and high cost, the neutron source provided by the invention has small size, simple system and low cost. Compared with a neutron source for directly carrying out deuterium-tritium reaction on an ion source to generate neutron, the ion source has simple system, low cost and no tritium radioactive processing and circulating problem. The invention has very wide application prospect.

The invention provides a compact high energy proton source useful for medical isotope production and for other applications including transmutation of nuclear waste. The invention further provides a device that can be used to generate high fluxes of isotropic neutrons by changing fuel types. The invention further provides an apparatus for the generation of isotopes including but not limited to ¹⁸F, ¹¹C, ¹⁵O, ⁶³Zn, ¹²⁴I, ¹³³Xe, ¹¹¹In, ¹²⁵I, ¹³¹I, ⁹⁹Mo, and ¹³N.

A borehole logging system for determining bulk density, porosity and formation gas/liquid fluid saturation of formation penetrated by a borehole. Measures of fast neutron radiation and inelastic scatter gamma radiation, induced by a pulsed neutron source, are combined with an iterative numerical solution of a two-group diffusion model to obtain the formation parameters of interest. Double-valued ambiguities in prior art measurements are removed by using the iterative solution of the inverted two-group diffusion model. The system requires two gamma ray detectors at different axial spacings from the source, and a single neutron detector axially spaced between the two gamma ray detectors. The system can be embodied as a wireline system or as a logging-while-drilling system.

A method and apparatus are provided for correcting gamma ray data representative of gamma ray energies for spectral degradation. The method and apparatus include degrading reference gamma ray spectra. At least one correction factor is calculated between the degraded gamma ray spectra and the reference gamma ray spectra. The gamma ray data are then corrected using a calculated correction factor. Another method is provided for determining a correction factor for correcting data representative of gamma ray energies for spectral degradation. The method includes disposing a downhole tool in a simulated environment representative of actual downhole conditions, the tool including a neutron source and at least one gamma ray detector. The temperature of at least one of the gamma ray detectors of the tool is then varied while the simulated environment is irradiated with neutrons emitted from the neutron source. Gamma ray energy signals are then detected at the at least one detector in response to gamma rays produced during nuclear reactions between the neutrons and materials in and of the simulated environment. A characteristic of the simulated environment is then determined along with a characteristic of the at least one detector. The determined characteristics of the simulated environment and of the at least one detector are then correlated to determine at least one correction factor.

A system for measuring the size of a borehole penetrating an earth formation is disclosed. The system uses a neutron source and a least one neutron detector. The neutron detector responds primarily to the composite hydrogen content of material within the borehole and formation upon irradiation by the neutron source. A partition response function is used to delineate the portion of the detector response resulting from borehole and from the formation. Since the detector response from the borehole can be isolated using the partition function and the hydrogen content of the borehole fluid is generally known, the size of the borehole can be determined from borehole response portion of the composite detector response if combined with a neutron porosity measurement of the formation. The neutron porosity measurement can be obtained independently, or by combining the neutron detector response with the response of a second neutron detector at a different axial spacing from the neutron source. The system is applicable in both logging-while-drilling and wireline logging operations.

The invention discloses a neutron diffraction residual stress determination device and a method. The device is characterized by using the reactor neutron source, carrying out monochromatization by a monochromator to obtain a required monochromatic neutron beam at a certain wavelength, and using the neutron beam to detect the residual stress. According to the invention, because the neutrons are uncharged, and when the neutrons interact with substance, the neutrons have no effect with extranuclear electons, charge Coulombian force obstacle has no need to overcome, thus low energy neutrons can enter in atoms; the neutron absorption of great majority of materials is low, thus the penetration depth of incoming neutron beam is deep. Simultaneously by collimator and slit collimation, the limitedneutron beam has high space resolution ratio, a three-dimensional lossless and deep stress test of a test piece is realized by translation of three directions which are vertical to each other and rotation around testing central point, and the defect that an X-ray and a synchrotron radiation residual stress determination device can only losslessly determine the residual stress of the crystal material surface and subsurface is overcome.

Non-destructive testing apparatus may comprise a photon source and a source material that emits positrons in response to bombardment of the source material with photons. The source material is positionable adjacent the photon source and a specimen so that when the source material is positioned adjacent the photon source it is exposed to photons produced thereby. When the source material is positioned adjacent the specimen, the specimen is exposed to at least some of the positrons emitted by the source material. A detector system positioned adjacent the specimen detects annihilation gamma rays emitted by the specimen. Another embodiment comprises a neutron source and a source material that emits positrons in response to neutron bombardment.

A nuclear-powered plant for systems of up to about 100 MWs with a confinement section where the reaction takes place in a core having a reactive thorium/uranium-233 composition, and where an external neutron source is used as a modulated neutron multiplier for the reactor core output. The core is housed in a containment structure that radiates thermal energy captured in a multiple-paths heat exchanger. The exchanger heat energy output is put to use in a conventional gas-to-water heat exchanger to produce commercial quality steam.