31 results about "Prompt neutron" patented technology

A neutron detector utilizing a sol-gel absorber incorporating a fissionable material and an activation disk. Preferably utilizing Li-6 and B-10 as fissionable material and Ag-109 as activation disk material for increased sensitivity and better differentiation of thermal versus prompt neutrons and neutrons versus other radiation fragments.

In accordance with embodiments of the invention, at least the potential presence of Special Nuclear Material (“SNM”) is determined by the detection of prompt neutrons, prompt gamma rays, delayed neutrons, and / or delayed gamma rays from photofission, via time-of-flight (“TOF”) spectroscopic methods. Methods and systems are disclosed.

Methods and systems for non-intrusively detecting the existence of fissile materials in a container via the measurement of energetic prompt neutrons are disclosed. The methods and systems use the unique nature of the prompt neutron energy spectrum from photo-fission arising from the emission of neutrons from almost fully accelerated fragments to unambiguously identify fissile material. The angular distribution of the prompt neutrons from photo-fission and the energy distribution correlated to neutron angle relative to the photon beam are used to distinguish odd-even from even-even nuclei undergoing photo-fission. The independence of the neutron yield curve (yield as a function of electron beam energy or photon energy) on neutron energy also is also used to distinguish photo-fission from other processes such as (γ, n). Different beam geometries are used to detect localized samples of fissile material and also fissile materials dispersed as small fragments or thin sheets over broad regions. These signals from photo-fission are unique and allow the detection of any material in the actinide region of the nuclear periodic table.

A cargo inspection system and active inspection methods for operating the same to confirm or clear a presence of explosives and / or nuclear materials in cargo. The active inspection methods use high-energy photons and / or neutrons to induce fission, and measure prompt neutrons, delayed neutrons, and delayed gamma-rays. Additionally, if one or more suspect objects are identified within the cargo with a preceding radiographic or computed tomography scan, a microprocessor calculates a position that produces optimal active inspection signals. The cargo or one of a primary radiation source, a secondary radiation source, or one or more radiation detectors are moved to this calculated position before fission occurs.

The present specification discloses a system for detecting nuclear material based on at least one source of probing radiation and the radiation signatures generated from interrogating an object under inspection. In addition, the present specification describes a threshold-activation detector capable of detecting prompt neutrons, via the activation, after the source's blinding radiation has stopped. The threshold-activation detector can be manufactured from liquid fluorocarbons that allow for the detection of beta radiation and gamma rays.

The invention discloses a prompt neutron logging and uranium ore quantity determining technology based on an above-thermal neutron time spectrum. Specifically, fast neutrons, i.e. virgin neutrons are emitted to stratum rock in a drilled hole in a pulse way, the virgin neutrons are moderated to thermal neutrons, and the thermal neutrons induce 235U to be fissioned and radiate uranium fission prompt neutrons, i.e. secondary neutrons. The virgin neutrons and the secondary neutrons are moderated to above-thermal neutrons and thermal neutrons with time; then the above-thermal neutron time spectrum is recorded, two coefficients, i.e. 1 / t2 and 1 / t1 which indicate the virgin neutron moderating capacity and the uranium fission sustaining capacity are extracted, nE(t1) / nE(t2) is defined as a fission / moderation ratio and a stratum rock uranium quantity determining algorithm is established according to the fission / moderation ratio. The invention additionally discloses an above-thermal neutron detector and a time spectrometer which are used for uranium ore pulsed neutron logging, and a real-time uranium quantity determining algorithm based on the above-thermal neutron time spectrum and an ore formation.

Methods and systems for non-intrusively detecting the existence of fissile materials in a container via the measurement of energetic prompt neutrons are disclosed. The methods and systems use the unique nature of the prompt neutron energy spectrum from neutron-induced fission arising from the emission of neutrons from almost fully accelerated fragments to unambiguously identify fissile material. These signals from neutron-induced fission are unique and allow the detection of any material in the actinide region of the nuclear periodic table.

The invention discloses a data processing method for measuring prompt neutron attenuation parameters for a reactor. The method includes the alpha reactivity measurement principle that rho equals to (alpha-alpha 0) / alpha 0, wherein alpha and alpha 0 are the prompt neutron attenuation parameters, the unit of the parameters is s-1, rho is reactivity, and the unit of the reactivity is beta eff. The invention further includes the following steps that firstly, a data point n of the prompt neutron attenuation parameter alpha i taking participation in fitting is determined; secondly, a control rod for scaling is determined, the scale is represented by H, the unit is centimeter, the control rod is lifted to the top according to a rod lifting program, the control rod on the periphery is kept static after critical leveling, then the control rod is evenly inserted to the bottom in n steps, and one corresponding alpha i value is obtained each time the control rod is inserted by one Hi rod position, wherein n is a natural number larger than zero; thirdly, each time the control rod is inserted to the Hi rod position, the emission frequency of pulse neutrons is adjusted according to the estimated alpha i values, so that in one pulse period, attenuation of the prompt neutrons is right completed, delayed neutrons are close to the bottom, and one alpha i value is obtained by means of a measurement curve according to least squares fitting.

The present invention includes a method for radiation detection. The present invention utilized boron-coated detectors as a new alternative to large 3He tubes that will address the timing limitations of 3He-based detectors in active interrogation systems, by providing a 100-times faster ion collection time. This may enable the counting of prompt neutrons starting within 10 μs following each gamma ray pulse. Current 3He-based detectors can only count delayed neutrons, and the linac pulse rate is severely limited by the lengthy times required to count these very late neutrons. If detection of the prompt component can be achieved, up to 150 times more neutrons can be detected in each pulse and pulse rate can be increased by more than 10 fold, giving a net sensitivity gain of 1500 while using the same detection array and linac.

The invention discloses a uranium ore logging method fusing a natural gamma energy spectrum and a prompt neutron time spectrum for uranium ore exploring and mining, and a scale parameter calculating method. Specifically, according to the uranium ore logging method, the natural gamma energy spectrum formed by natural radioactive elements and the prompt neutron time spectrum caused by pulsed neutronuranium fission in a rock ore layer are measured point by point along a drilled hole, and according to the natural gamma energy spectrum and the prompt neutron time spectrum, the contents of the natural radioactive elements of uranium, thorium, radium, potassium and the like in the rock ore layer are analyzed; and the calculating method of scale parameters such as the conversion coefficient, thesensitivity factor and background response of the natural radioactive elements is also included. Organic combination and data fusion of the two nuclear logging methods are achieved, especially for a single nuclear logging method for uranium ore quantification, radioactive balance correction of uranium, radium and radon is not needed, thus the uranium ore logging method has the characteristics thatcore sampling and chemical analysis are not needed, and has the advantages that the drilling efficiency is improved, the exploring cost is lowered, and the uranium quantification cycle is shortened,and uranium ore quantification on-site analysis can also be achieved through computer programming.

The invention discloses a prompt uranium fission neutron logging technique based on the epithermal neutron and thermal neutron ratio. The technique is specifically characterized in that in boreholes, fast neutrons, also called virgin neutrons, are transmitted to formation rock by means of pulsing; the virgin neutrons are successively moderated by in-well medium into epithermal neutrons and thermal neutrons; the thermal neutrons induce 235U fission to radiate prompt uranium fission neutrons, also called secondary neutrons; the secondary neutrons are successively moderated into epithermal neutrons and thermal neutrons, inducing 235U fission again; from any moment t after the virgin neutrons are moderated into the thermal neutrons, the total nE(t) of existing epithermal neutrons in the formation rock is in direct proportion to the total nT(t) of existing thermal neutrons and uranium content qu, namely nE(t)<nT(t) qu. By using a bi-neutron detector and a dual-time detector disposed in the invention to measure time spectra of the epithermal and thermal neutrons and defining an attenuation ratio of the epithermal neutrons to the thermal neutrons as 'E / T', from a moment, when the virgin neutrons are moderated into the thermal neutrons, to any moment, a uranium quantitative real-time algorithm based on saturated seams is constructed.

The invention discloses a comprehensive on-line measuring method of prompt neutron attenuation constant. The method mainly comprises the following stages: 1) collecting neutron pulse to obtain the time distribution of neutron pulse generated by neutron source and detecting body excited by the neutron source; 2) partitioning the collected data pack according to a given length, calculating the correlation function and power spectrum density of each block of neutron signal; 3) adopting the correlated fitting method to treat the correlation function so as to calculate the prompt neutron attenuation constant, adopting the break frequency method to treat the power spectrum density so as to calculate the prompt neutron attenuation constant; and 4) performing a comprehensive treatment to the results of the two different methods to obtain the final measuring result. The method can be used to estimate the prompt neutron attenuation constant both in time domain and frequency domain and perform measurement at the same time, thus as the operating precision of measurement increases gradually, the aim of on-line measurement is finally realized.

An in-core nuclear detector for detecting the neutron population surrounding the detector. The detector is an ion chamber having a cylindrical outer electrode that is insulated from a central electrode and capped to contain an Argon gas. An electron radiator that produces prompt neutron capture gamma radiation that is substantially, directly proportional to the local neutron population is disposed between the outer tubular electrode and the central electrode.

The present specification discloses a system for detecting nuclear material based on at least one source of probing radiation and the radiation signatures generated from interrogating an object under inspection. In addition, the present specification describes a threshold-activation detector capable of detecting prompt neutrons, via the activation, after the source's blinding radiation has stopped. The threshold-activation detector can be manufactured from liquid fluorocarbons that allow for the detection of beta radiation and gamma rays.

The present invention includes a method for radiation detection. The present invention utilized boron-coated detectors as a new alternative to large 3He tubes that will address the timing limitations of 3He-based detectors in active interrogation systems, by providing a 100-times faster ion collection time. This may enable the counting of prompt neutrons starting within 10 μs following each gamma ray pulse. Current 3He-based detectors can only count delayed neutrons, and the linac pulse rate is severely limited by the lengthy times required to count these very late neutrons. If detection of the prompt component can be achieved, up to 150 times more neutrons can be detected in each pulse and pulse rate can be increased by more than 10 fold, giving a net sensitivity gain of 1500 while using the same detection array and linac.

An in-core nuclear detector for detecting the neutron population surrounding the detector. The detector is an ion chamber having a cylindrical outer electrode that is insulated from a central electrode and capped to contain an Argon gas. An electron radiator that produces prompt neutron capture gamma radiation that is substantially, directly proportional to the local neutron population is disposed between the outer tubular electrode and the central electrode.

An in-core nuclear detector for detecting the neutron population surrounding the detector. The detector is an ion chamber having a cylindrical outer electrode that is insulated from a central electrode and capped to contain an Argon gas. An electron radiator that produces prompt neutron capture gamma radiation that is substantially, directly proportional to the local neutron population is disposed between the outer tubular electrode and the central electrode.

Methods and systems for non-intrusively detecting the existence of fissile materials in a container via the measurement of energetic prompt neutrons are disclosed. The methods and systems use the unique nature of the prompt neutron energy spectrum from neutron-induced fission arising from the emission of neutrons from almost fully accelerated fragments to unambiguously identify fissile material. These signals from neutron-induced fission are unique and allow the detection of any material in the actinide region of the nuclear periodic table.

The invention discloses a uranium fission prompt neutron logging control method combined with a natural gamma-detector. The method comprises the steps that a natural gamma-energy spectrum with the background removed at the current depth interval is acquired according to a fixed interval depth value, and the obtained gamma-energy spectrum can be free of the interference of the stratum environment;the energy spectrum with the background removed is subjected to time domain-frequency domain conversion, frequency spectrum ingredients of an interference source are eliminated in the frequency domain, and the needless frequency spectrum ingredients are restrained. Finally, the denoised energy spectrum data total counting rate is compared with the detection limit counting rate of instrument scalemarks, and the opportunity of opening or closing a neutron generator is judged. According to the method, the high efficiency of natural gamma-logging and the accuracy of uranium fission prompt neutronlogging are combined, the uranium fission prompt neutron logging efficiency can be improved fast and effectively, and important practical value is achieved.

The invention discloses a prompt-neutron-attenuation-constant obtaining method. The prompt-neutron-attenuation-constant obtaining method includes the following steps that periodic pulse neutrons are injected into a subcritical reactor through a pulse neutron source; in a target pulse period, neutron counting rate time spectrums of different positions in the subcritical reactor are obtained; specific values of the obtained neutron counting rate time spectrums of the different positions are computed, and relative neutron counting rate time spectrums are obtained; through the relative neutron counting rate time spectrums, a target moment when prompt-neutron higher-order harmonic attenuation is completed is determined; in the target pulse period, the neutron counting rate between the target moment and an ending moment of the pulse period is subjected to exponential attenuation fitting processing, and a prompt-neutron fundamental-wave attenuation constant is obtained. The more-accurate prompt-neutron fundamental-wave attenuation constant under the condition that interference of prompt-neutron higher-order harmonic waves does not exist can be obtained. The invention also discloses a prompt-neutron-attenuation-constant obtaining device, equipment and system and a readable storage medium, and the prompt-neutron-attenuation-constant obtaining device, equipment and system and the readable storage medium have corresponding technical effects.

The invention discloses a uranium ore quantitative method for fused prompt neutron time spectrum logging to correct natural gamma total logging in the fields of uranium ore exploration and in-situ leaching uranium mining. Specifically, it refers to: for the uranium-bearing rock ore layer in the drill hole, using two types of logging data of natural gamma total logging and prompt neutron time spectrum logging, constructing a well that is based on natural gamma total logging and has "uranium -Radium-Radon” balance correction uranium ore quantitative interpretation method; and use the logging data of standard model wells to construct the calculation method of scale parameters such as conversion coefficient and background response required for uranium ore quantification. Compared with the uranium ore quantitative method of single prompt neutron time spectrum logging or natural gamma total logging, the present invention does not require rock core sampling and chemical analysis methods, and can not only obtain the "uranium-radium-radon" balance coefficient, but also It can greatly increase the logging speed, and thus has the advantages of improving drilling efficiency, reducing exploration costs, shortening the uranium quantification period, and can realize the on-site analysis of uranium ore quantification through computer programming.

The invention discloses a slurry density correction method based on uranium fission instantaneous neutron logging data. A numerical logging model is established through Monte Carlo (MCNP) simulation;according to the change relation of transient fission neutron uranium mine logging thermal neutrons and epithermal neutron densities along with the stratum environment, related factors influencing thelogging neutron time spectrum are studied; the influence of different mud densities under the same borehole diameter on E / T (the ratio of epithermal neutrons to thermal neutrons) in transient fissionneutron uranium mine logging is discussed, a correction function influenced by the stratum environment is given through an MCNP simulation data fitting method, and the influence of different mud densities on uranium content measurement can be effectively reduced.

The invention discloses a uranium well logging method and calibration parameter calculation method for uranium ore prospecting and fusion of natural gamma energy spectrum and prompt neutron time spectrum. Specifically, it refers to measuring the natural gamma energy spectrum formed by natural radioactive elements in the rock ore layer and the prompt neutron time spectrum caused by pulsed neutron uranium fission point by point along the borehole, and analyzing the uranium, thorium, radium, Uranium ore logging methods for the content of natural radioactive elements such as potassium, and calculation methods for scaling parameters such as conversion coefficients, sensitivity factors, and background responses. The present invention is an organic combination and data fusion of two types of nuclear logging methods, especially for a single nuclear logging method for uranium ore quantification. It does not require core sampling and chemical analysis, and has the advantages of improving drilling efficiency, reducing exploration costs, and shortening the uranium quantification cycle. It can also realize quantitative on-site analysis of uranium ore through computer programming.

The invention relates to a method for rapidly acquiring neutron absorbed dose, in particular to a method for rapidly acquiring neutron absorbed dose based on Monte Carlo simulation data and considering atmospheric humidity influence, which is used for solving the problem that the influence of atmospheric humidity on neutron absorbed dose is generally not considered in the existing neutron absorbed dose acquisition method. Even if the influence of the atmospheric humidity on the neutron absorption dose is considered, the time consumption is long, and the distribution of the neutron absorption dose field cannot be quickly obtained according to any given relative humidity condition. According to the neutron absorbed dose rapid acquisition method considering the atmospheric humidity influence, neutron absorbed dose reference data under a reference humidity condition is utilized, and a humidity correction coefficient is obtained according to a relational expression among the humidity correction coefficient, a mass distance and an air water content; and rapid acquisition of the neutron absorption dose field under any given atmospheric humidity condition is realized.

The invention discloses a uranium ore well logging tool and a uranium quantitative equation for integrating natural gamma energy spectrum and neutron time spectrum, and specifically refers to: a device capable of measuring the formation of natural radioactive elements in rock ore layers point by point along the borehole The basic structure of the uranium logging tool of the natural gamma energy spectrum and the prompt neutron time spectrum caused by the pulsed neutron uranium fission, and the use of these two types of logging data to determine the natural radioactivity of uranium, thorium, radium, potassium, etc. Quantitative equations for elemental content. The present invention is an organic combination and data fusion of two types of nuclear logging methods, especially for the natural gamma logging method of uranium ore quantification. Core sampling and chemical analysis have the advantages of improving drilling efficiency, reducing exploration costs, shortening the uranium quantification cycle, etc., and can also realize the quantitative analysis of uranium ore on the drilling site through computer programming.

The invention relates to the field of reactor testing, in particular to a neutron source intensity calculation method, a storage medium and a real-time online reactivity meter. The neutron source intensity calculation method comprises the steps that a power level n in a deep subcritical stable state is obtained through measurement; keff or reactivity rho in the deep subcritical state, and instantaneous neutron average substitution time l or instantaneous neutron service life l0 are calculated; and the neutron source intensity is calculated according to the rho, the n and the l, and when Keff is smaller than 0.98 or rho is smaller than -2000 pcm, the measurement error of the neutron source intensity meets the engineering application requirement. The neutron source is calculated through theneutron source intensity calculation method, the measurement error of the neutron source intensity can be guaranteed, and therefore the calculation correctness and full-range coverage of reactivity ina low-power state are guaranteed.

The invention discloses a prompt neutron logging and uranium ore quantity determining technology based on an above-thermal neutron time spectrum. Specifically, fast neutrons, i.e. virgin neutrons are emitted to stratum rock in a drilled hole in a pulse way, the virgin neutrons are moderated to thermal neutrons, and the thermal neutrons induce 235U to be fissioned and radiate uranium fission prompt neutrons, i.e. secondary neutrons. The virgin neutrons and the secondary neutrons are moderated to above-thermal neutrons and thermal neutrons with time; then the above-thermal neutron time spectrum is recorded, two coefficients, i.e. 1 / t2 and 1 / t1 which indicate the virgin neutron moderating capacity and the uranium fission sustaining capacity are extracted, nE(t1) / nE(t2) is defined as a fission / moderation ratio and a stratum rock uranium quantity determining algorithm is established according to the fission / moderation ratio. The invention additionally discloses an above-thermal neutron detector and a time spectrometer which are used for uranium ore pulsed neutron logging, and a real-time uranium quantity determining algorithm based on the above-thermal neutron time spectrum and an ore formation.