417 results about "Neutron source" patented technology

The invention belongs to the technical field of radiation protection, and particularly relates to a neutron shielding material optimization method based on machine learning and chaotic mapping NSGA-III, and the method comprises the steps: 1, determining an optimization target, and building a multi-target neutron composite shielding material attribute optimization model; step 2, building a Monte Carlo model to simulate and calculate shielding doses of the composite shielding materials with different attributes to a neutron source, and obtaining a data set with the material component proportion and thickness as characteristic attributes and the shielding doses as labels; and step 3, optimizing initial parameters of the BP neural network by adopting an improved particle swarm optimization algorithm, improving calculation precision and operation efficiency of the neural network, and training a neural network regression model by taking the data set obtained in the step 2 as a sample to complete establishment of a shielding dose prediction model and the like. An improved particle swarm optimization algorithm for improving Levy flight mechanism strategy optimization is designed to optimize initial parameters of the BP neural network, and the precision and operation efficiency of a neural network shielding dose regression prediction model are improved.

The invention relates to the technical field of gamma-ray spectrum analysis, particularly provides a gamma-ray detector activation analysis method and a PGNAA detection system, and aims to solve the problems that gamma rays obtained by detection of an existing gamma-ray detector comprise rays generated by decay of crystals after activation in a neutron field; therefore, the component detection result of the to-be-detected sample is not accurate. In order to achieve the purpose, the activation analysis method for the gamma detector comprises the steps that a to-be-detected sample is irradiated through a neutron source; repeatedly collecting a plurality of groups of gamma-ray energy spectrums of the sample to be detected by using a gamma-ray detector; constructing an energy spectrum signal matrix based on the gamma-ray energy spectrum of the to-be-detected sample, wherein the energy spectrum signal matrix is a mixed signal composed of instant gamma rays generated by neutron activation of the to-be-detected sample, environmental background gamma rays and interference signals generated by crystal activation in a gamma detector; and obtaining the effective instant gamma ray based on the energy spectrum signal matrix. The self-interference influence of the detector is effectively reduced, and the target element content evaluation precision of the to-be-detected object is improved.

A method and system for identifying formation porosity and formation lithology. The method may include disposing a PNL tool into a borehole that is disposed in a formation, emitting a neutron from a neutron source on the PNL tool into the formation, and capturing one or more gammas expelled from formation in response to the neutron from the neutron source to form a plurality of pulsed neutron logging (PNL) measurements in a log. The method may further include identifying a formation porosity and a formation lithology with an artificial neural network that at least partially incorporates the PNL measurements.

The invention relates to the technical field of radiation therapy, in particular to a boron neutron capture therapy beam shaping device and a boron neutron capture therapy system. The beam shaping device for boron neutron capture therapy is used for beam shaping of a DT neutron tube generator. The interior of the beam shaping device is provided with a particle beam channel, and the particle beam channel is used for generating an initial neutron source through an incident proton beam. The beam shaping device comprises a value-added layer, a moderator, a filter layer, a reflecting layer, a collimator and a shielding layer, wherein the value-added layer, the moderator, the filter layer and the collimator are sequentially arranged from a target material to an outlet. And the axes of the particle beam channel, the value-added layer, the moderator and the collimator coincide. According to the beam shaping device, 14Mev high-energy neutrons from the DT neutron tube generator are shaped into hot / slow neutron beams meeting the BNCT treatment requirements, and impurities of fast neutrons and gamma rays are reduced to the maximum extent, so that the dosage precision and biological selectivity of treatment are effectively improved.

The invention discloses an ion source current control device and system, and relates to the field of circuits, the ion source current control device comprises a sampling circuit, a control circuit and a power supply circuit, the control circuit is connected with the sampling circuit, the ion source current of a neutron tube can be detected in real time, and power supply of a hot wire is controlled in real time by adopting a hardware circuit feedback mode. The current stability of the ion source is rapidly maintained, the calculation delay of a software mode is eliminated, and the control circuit can realize the adjustment of the duty ratio of the output pulse signal through the difference value between the first voltage value and the second voltage value, so as to realize the accurate control of the neutron tube hot wire power supply process. The whole control process is realized through a hardware circuit, the response speed is high, the output is stable, the stability of the output ion source current is ensured, the situations such as jitter are avoided, the application range of the neutron source is expanded, and wide popularization of the neutron source is facilitated.

The invention discloses a thyristor failure test device, which relates to the technical field of thyristor life test, and comprises a power supply, a protective resistor, an artificial neutron source, a data acquisition device and a processing module, and is characterized in that the power supply is used for providing direct current bias voltages with different sizes and different polarities for a sample thyristor; the artificial neutron source is used for enabling random single-particle burnout events to occur in the sample thyristor; the protection resistor is used for limiting main loop current; the data acquisition equipment is used for acquiring bias voltage signals on the sample thyristors in real time; and the processing module is used for recording the occurrence time of the single-particle burnout event according to the bias voltage signal on the sample thyristor when the single-particle burnout event occurs in the sample thyristor, and fitting the occurrence time of the single-particle burnout event and the corresponding bias voltage signal to obtain the failure rate of the thyristor. According to the invention, the condition of irradiation failure of the thyristor under voltage bias under the actual working condition can be truly reflected.

Systems and methods for measuring the content of an element in a soil comprises: a neutron source for irradiating the soil with neutrons; a detector assembly configured to detect an INS gamma spectrum of the soil; an instrument for measuring a moisture content of the soil; and a processor in communication with the detector assembly, the processor configured to: apply a moisture calibration coefficient to calculate a net peak area of a characteristic peak of the element in the INS gamma spectrum, the moisture calibration coefficient calculated to account for the moderation of fast neutrons by hydrogen atoms of water present in the irradiated soil at the location under analysis; and generate a concentration of the element in the soil. The instrument for measuring a moisture content of the soil may comprise the detector assembly. Systems and methods incorporating a temperature-controlled housing for the gamma detector assembly are also provided.

The invention provides a device and a method for detecting residual stress and defects of a diaphragm by a neutron source. The device comprises a neutron source, a neutron detector, a diaphragm fixing assembly and a console, and the residual stress and defects of the diaphragm are nondestructively detected through a neutron diffraction technology. The diaphragm is fixed through the diaphragm fixing assembly, and the neutron beam of the neutron source is adjusted, so that the neutron beam completely covers the diaphragm; adjusting the angle of the diaphragm through the diaphragm fixing assembly, repeatedly recording stable diffraction signals to obtain multiple groups of strain data, and analyzing and processing to generate a residual stress nephogram and a defect distribution result. According to the scheme, accurate detection of residual stress and defects of the to-be-detected diaphragm is realized through the neutron diffraction technology, the method has the advantage of nondestructive detection, avoids damage to the diaphragm, is suitable for detection of various diaphragm materials, is accurate in measurement and simple and convenient to operate, reduces manual operation errors, and improves the detection accuracy. And meanwhile, the data is further analyzed and processed by utilizing cloud computing and a big data technology, so that the detection accuracy and efficiency are improved.

The invention provides an isotope production method based on irradiation of a side reflecting layer of a pebble-bed high-temperature gas cooled reactor. The method comprises the following steps: transforming a neutron source duct and a physical starting device duct in the side reflecting layer of the pebble-bed high-temperature gas cooled reactor; designing an isotope target on the basis of the production requirement of the isotope to be produced and the reconstructed pore parameters, and adjusting the isotope target according to the safety analysis result of the isotope produced by online irradiation of the side reflecting layer; designing an isotope irradiation device for carrying out in-pile and out-pile operation on the isotope target, and calculating isotope irradiation theoretical parameters; and loading an isotope target into the modified pore channel through an isotope irradiation device, performing online irradiation according to isotope irradiation theoretical parameters, and discharging the isotope target after irradiation is completed. According to the method, the radioactive isotope is generated through online irradiation of the side reflecting layer of the pebble-bed high-temperature gas cooled reactor, so that the application scene of the reactor is enriched, and the utilization efficiency of the reactor is improved.

The invention discloses a high-precision single crystal blade residual stress measurement method based on a neutron diffraction technology, which further amplifies the high-precision advantage of a stress spectrometer based on a reactor neutron source, and integrates the technical advantages of a Kappa goniometer and an Euler ring of texture measurement equipment. And high-precision measurement of the residual stress of the single crystal blade based on the neutron diffraction technology is realized. According to the method, the neutron diffraction technology is utilized to carry out high-precision measurement of the residual stress of the single crystal blade with the complex and fine configuration, so that accurate measurement of the residual stress of key positions such as blade body air film hole peripheries and internal reinforcing ribs is realized, guidance is provided for the processing technology, and reliable data support is provided for evaluation of the service performance and the service life of the blade. Meanwhile, the method can also be applied to high-precision measurement of three-dimensional residual stress of other complex structure components.

The invention provides a BNCT important clinical parameter prediction method based on a BP neural network. The method comprises the steps of obtaining neutron energy spectrum and dose distribution data; constructing a multi-layer BP neural network model and training the multi-layer BP neural network model; selecting a treatment position of an outlet of a beam shaper of the BNCT as a point to be measured, and measuring a neutron energy spectrum and neutron distribution at the measurement point; using the trained multilayer BP neural network model to predict distribution of boron dose, hydrogen dose, nitrogen dose and gamma dose in tumors and normal tissues in a human body corresponding to neutron energy spectrum and neutron distribution, and calculating related clinical parameters. According to the method, the neutron source for the BNCT can be rapidly and accurately evaluated, uncertainty and risks in treatment can be reduced through accurate parameter prediction, and the safety of the BNCT is improved; reliable parameter prediction is provided for clinicians, the accuracy and efficiency of clinical decision making are improved, the treatment process is optimized, and therefore the overall medical cost is reduced.

The invention relates to a chemical control method and system in a unit overhaul shutdown period when reactor core components of a nuclear power station are damaged. The chemical control method comprises the following steps: determining the damage type of the reactor core components; if the damage type of the reactor core part is fuel damage, performing preparation before overhaul of the fuel damage unit, and after the preparation before overhaul is completed, performing chemical control in the descending period of overhaul of the fuel damage unit; and if the damage type of the reactor core part is neutron source damage, executing preparation before overhaul of a neutron source damage unit, and after the preparation before overhaul is completed, executing chemical control in an overhaul descending period of the neutron source damage unit. According to the method, chemical control can be carried out on a unit with fuel damage or neutron source damage in the overhaul descending period, dosage rising caused by deposition or unfavorable removal control is avoided, and the overhaul period can be prevented from being delayed.

The invention relates to the technical field of compressed air energy storage salt cavern engineering, and provides a compressed air energy storage salt cavern cavity air-tight seal monitoring method and system, and the method comprises the steps: S1, monitoring preparation; s2, sealing and monitoring brine; s3, gas seal monitoring of the injection-production string; s4, open hole section air-tight seal monitoring; when the three kinds of monitoring meet the requirements at the same time, it is judged that the air sealing performance of the compressed air energy storage salt cavern cavity is qualified. The system comprises an injection and production pipe column, a test pipe column, a first pressure gauge, a second pressure gauge, a packer, a salt cavern cavity brine sealing performance monitoring unit, an injection and production pipe column gas sealing performance monitoring unit and a well body open hole section sealing performance monitoring unit. The method is suitable for air-tight seal monitoring of the compressed air energy storage salt cavern gas storage, the mode that a neutron source is used for measuring a gas-liquid interface is not used, the monitoring process is optimized, monitoring indexes are quantified, it is ensured that the salt cavern cavity sealing performance meets the sealing requirement of compressed air energy storage gas storage engineering, and the engineering utilization efficiency is improved.

A neutron source irradiation device capable of switching gas paths disclosed by the present invention comprises a gas path switching rotor assembly, a transmission pipeline and a plurality of storage pipelines, the transmission pipeline is provided with an electromagnetic chuck, and a neutron source is stored in each storage pipeline. And the transmission pipeline can be communicated with the different storage pipelines through rotation of the gas path switching rotor assembly, so that neutron sources in the different storage pipelines can reach the electromagnetic chuck through the transmission pipeline. Neutron sources at different positions can be transmitted to the same position for irradiation, an independent transmission irradiation structure is provided, the irradiation position structure is simple, the scattering influence can be reduced, meanwhile, different neutron sources have good repeatability and consistency at the irradiation positions, position adjustment of a measured instrument is not needed, the verification efficiency is improved, and the detection cost is reduced. And the stability and consistency error of the generated neutron radiation field are ensured.

The invention relates to the technical field of neutron sources and discloses a rotating neutron target heat dissipation method, a rotating neutron target and a neutron target system.The rotating neutron target heat dissipation method is characterized in that a heat exchange structure is arranged on the side face of a target piece, and a cooling medium is introduced into the heat exchange structure and used for assisting in heat dissipation of the target piece; according to the invention, the technical problem that in the prior art, a beam bombardment area coincides with the cooling water flow channel of the neutron target, the heat dissipation effect of the target sheet can be achieved, neutrons generated by the neutron target in the beam direction are slowed down, and the quality of the neutron beam is reduced can be solved; according to the invention, on the premise of maintaining effective heat dissipation and cooling of the neutron target, a flow bombardment area can be prevented from being overlapped with the cooling water flow channel of the neutron target, so that high-quality neutron beams can be output at the same time.

The invention relates to a neutron magnetic focusing device control system, and the system comprises a front-end sensing unit which is used for collecting the angle, temperature and other data of a neutron magnetic focusing device; the core control unit is used for realizing synchronous control and temperature protection of a motor and a neutron source T0 signal based on data acquired by the front-end sensing unit; the feedback compensation unit feeds back the equipment state in real time and dynamically compensates the phase deviation; the man-machine interaction unit supports local and remote dual-mode control; through cooperative work of multiple units, the system can realize high-precision synchronous control, real-time state monitoring and fault alarm, the operation stability and efficiency of a neutron magnetic focusing device are effectively improved, and reliable technical support is provided for a neutron scattering experiment.

A substance composition analysis system includes: a neutron source (10) configured to generate neutrons acting on a material (IM) to be inspected; the neutron moderation structure (20) surrounds the neutron source (10) and is configured to moderate neutrons generated by the neutron source (10); the material accommodating cavity (30) is configured to accommodate the detected material (IM); the detector assembly (40) is configured to capture a characteristic signal generated after the detected material (IM) is bombarded by neutrons; wherein at least part of the neutron moderation structure (20) is located in the material containing cavity (30), so that at least part of the neutron moderation structure (20) is buried in the detected material (IM). The utilization rate of neutrons emitted by the neutron source can be improved.

A neutron imaging system that includes a central neutron source configured to produce source neutrons, wherein the central neutron source comprises a beam target, a moderator chamber surrounding at least a portion of the beam target, the moderator chamber housing a moderator, and a re-entrant cone extending into the moderator chamber. The re-entrant cone includes an entrance surface having a concave curvature facing the beam target. The entrance surface encloses a cone chamber, isolating the cone chamber from the moderator.

A nuclear instrumentation device (100) comprises: a waveform discrimination circuit (41) that extracts a neutron-derived pulse signal from a pulse signal detected by a detector (1); a pulse count circuit (42) that periodically counts the neutron-derived pulse signal; a count rate conversion circuit (43) that converts the pulse count value into a count rate; a zero count circuit (45) that calculates a continuation period in which the pulse count value of the pulse count circuit (42) becomes zero; a time constant selection circuit (46) that selects a time constant according to the period calculated by the zero count circuit (45) when the pulse count value in the pulse count circuit (42) is zero, and that selects a larger time constant as the count rate decreases and a smaller time constant as the count rate increases when the pulse count value is not zero; and an integration circuit (47) that calculates the count rate of neutrons in each period by using the selected time constant, the abovementioned circuits being composed of digital circuits.

According to the image processing method and device provided by the invention, aiming at the characteristics of source intensity fluctuation of an accelerator neutron source, instantaneity and randomness of neutron photography white spot noise and the like, a detection-positioning-replacement mechanism is adopted to process a multi-frame image sequence so as to realize image denoising. The method comprises the following steps: firstly, for each pixel position, judging whether each frame at the pixel position contains noise or not by using a noise reference value obtained based on time domain median filtering, and replacing the gray value of the noise-containing frame with the average value of the gray values of the noise-free frames at the pixel position; fusing the replaced frame sequences and traversing all pixel positions to obtain a primary denoising fusion image; and then, judging whether each fused pixel contains residual noise or not by using a spatial filtering method, and for each pixel containing the residual noise, carrying out gray value replacement of a noisy frame again by using another noise reference value which is not based on time domain filtering and traversing all pixel positions to obtain a secondary de-noised fused image.

A system includes one or more neutron sources configured to emit neutrons. The system also includes one or more electron detectors configured to detect electrons. Further, the system includes a control system comprising one or more processors. The control system is configured to determine a lithium concentration based on the electrons. Further, the control system is configured to generate a lithium extraction output based on the lithium concentration.

The invention discloses an accelerator neutron source solid-state lithium target cooling device, and relates to the technical field of accelerator neutron source medical application. An annular heat pipe is arranged on the outer ring of the side portion of an oxygen-free copper substrate, a plurality of liquid absorption cores are arranged on the inner wall of the heat pipe, and meanwhile an inner cavity of the heat pipe is filled with a working medium; when heat is generated, the heat is firstly transferred to the oxygen-free copper substrate, the evaporation section of the heat pipe is heated, the working medium in the wick is quickly evaporated and gasified, the generated steam flows to the condensation section under the driving of differential pressure and is condensed into liquid in the condensation section and releases heat, and the liquid generated by condensation returns to the evaporation section again under the capillary action of the wick. The space of the arranged heat pipe is large, and in the aspect of heat dissipation, the working medium is subjected to gas-liquid phase change in the heat pipe under the action of the liquid absorption core, so that the accelerator is rapidly dissipated, heat on the solid target material film can be rapidly taken away, and the cooling effect on the accelerator is greatly improved.

The invention belongs to the technical field of nuclear power plant subcritical degree determination, and particularly relates to a method for determining a subcritical degree by adopting a spatial effect of an external neutron source. Comprising the following steps: 1, obtaining a curve of the ratio of the subcritical degree to near-source and passive neutron detector signals through theoretical calculation; 2, obtaining measurement values of four source range neutron detectors and four intermediate range neutron detectors; 3, calculating a near-source and passive ratio; and 4, according to the ratio calculated in the step 3, searching a ratio curve of the subcritical degree and the signals of the near-source and passive neutron detectors so as to obtain the reactivity of the reactor core. The method has the beneficial effect that the subcritical degree cannot be obtained by directly measuring through an instrument when the power level of the reactor is lower. According to the method, the subcriticality can be quickly obtained in a chart form through the ratio of the near-source neutron detector signals to the passive neutron detector signals or the ratio of the passive neutron detector signals to the near-source neutron detector signals.

Embodiments of the present invention disclose a method, apparatus, device, and storage medium for determining neutron source intensity. The method includes: determining the source intensity of a primary neutron source as it changes over time after a reactor shutdown; determining the source intensity of a secondary neutron source as it changes over time after a reactor shutdown based on the determined thermal neutron flux density of a secondary neutron source; and determining the source intensity of a total neutron source as it changes over shutdown time based on the source intensity of the primary and secondary neutron sources, combined with predetermined spatial and energy spectrum factors, to ensure safe loading and startup of the unit. This method comprehensively considers the different locations and energy spectra of the primary and secondary neutron sources, which have different effects on the response of the off-core detectors, and combines the predetermined spatial and energy spectrum factors to determine the source intensity of the neutron source as it changes over time after a reactor shutdown, thereby achieving rapid and accurate determination of the neutron source intensity and providing a physical basis for reactor startup.

This invention relates to the field of neutron source technology, and particularly to a controllable isotope neutron source device based on ion migration and a method for generating neutrons. The device includes a casing, inside which are a target material module, a target ion migration system, a safety module, and an alpha particle source term. The target material module provides target nuclide ions. The alpha particle source term includes alpha radioactive nuclide material and target nuclide intercalation material. The safety module is composed of target nuclide intercalation material. The target ion migration system is connected to an external control field. Target nuclide ions migrate through the target ion migration system within the safety module and the alpha particle source term. This invention enables active controllability of the isotope neutron source, significantly improving safety. By ensuring sufficient contact between alpha particles and target nuclides to form a molecular intercalation structure, the (α,n) reaction efficiency is greatly improved. Furthermore, this neutron source can be used in combination with multiple modules according to application requirements, effectively increasing the neutron output flux.

The application relates to the technical field of medical data processing, and discloses a macroscopic cross-section database construction method, a dose determination method, a device and equipment, which comprises the following steps: setting multiple boron concentration values for the tissue types corresponding to a human body model; selecting corresponding neutron source parameters for the tissue types and the multiple boron concentration values, wherein the neutron source parameters comprise energy range values; dividing the energy range values into multiple discrete neutron energy groups; performing particle transport simulation based on the selected neutron source parameters, jumping between different neutron energy groups in the simulation process, and obtaining neutron reaction rates and neutron fluxes of the tissue types under the multiple boron concentration values and the multiple neutron energy groups; and obtaining neutron macroscopic cross-section values of the tissue types under the multiple boron concentration values and the multiple neutron energy groups based on the neutron reaction rates and the neutron fluxes, and constructing a multi-group macroscopic cross-section database. The application can improve the calculation efficiency of the radiation dose and improve the adaptability to individual metabolic differences during dose calculation.

The application discloses a GAN neural network multiple distortion suppression model based on a coordinate attention mechanism, obtains an original neutron radiographic image from a neutron source; proposes a brand-new neutron radiographic image degradation model; adds Gaussian blur, Gaussian noise, Poisson noise and noise obeying gamma distribution to the clear neutron radiographic image; uses real white spot noise to train the GAN neural network, simulates white spot noise and randomly adds the white spot noise to the clear neutron radiographic image; constructs a multiple distortion suppression model of the GAN neural network based on the coordinate attention mechanism; uses Huber loss to train the constructed GAN neural network based on the coordinate attention mechanism; inputs a real neutron radiographic image containing multiple distortions into the trained multiple distortion suppression model as input, predicts the original image of the real neutron radiographic image containing multiple distortions, and obtains a target result.

The invention relates to the technical field of medical data processing, and discloses a neutron source correction method and equipment for a radiotherapy planning system, and the method comprises the steps: obtaining a first value of a target physical quantity obtained based on physical experiment measurement, and obtaining a second value of the target physical quantity corresponding to the radiotherapy planning system; the physical experiment is used for quality guarantee; if it is determined that the deviation does not meet the preset requirement based on the first numerical value and the corresponding second numerical value of the target physical quantity, the target neutron input energy-angle spectrum is obtained through inversion by means of a regularization optimization model, so that the deviation meets the preset requirement; and correcting the neutron input energy-angle spectrum in the radiotherapy planning system based on the target neutron input energy-angle spectrum. According to the invention, the neutron input energy-angle spectrum in a radiotherapy planning system can be corrected, and the consistency of a simulation result and an experimental result is ensured, so that the requirement of boron neutron capture therapy on quality assurance is met.

The present application relates to the technical field of neutron source, and particularly provides a high-heat-carrying neutron target system, which aims to solve the problem of poor heat dissipation capacity of the neutron target system. To this end, the high-heat-carrying neutron target system comprises a base and a jet cylinder, the base comprises a first end portion and a second end portion; the jet cylinder is wrapped on the outer side of the base; and the high-heat-carrying neutron target system further comprises a turbulence structure, the turbulence structure comprises a first heat dissipation structure and a second heat dissipation structure for flowing cooling medium, the first heat dissipation structure is arranged on the base and penetrates through the base in the direction from the first end portion to the second end portion; and the second heat dissipation structure is arranged on the jet cylinder, the second heat dissipation structure is communicated with the first heat dissipation structure, and the cooling medium in the second heat dissipation structure flows into the first heat dissipation structure in a preset direction to form turbulence for the cooling medium in the first heat dissipation structure. In the present application, the second heat dissipation structure is used to effectively increase the turbulence degree of the cooling medium in the first heat dissipation structure, thereby greatly improving the heat exchange effect of the neutron target system.