Neutron flux determination method and device applied to dating of samarium-neodymium isotope system

Abstract

The embodiment of the invention provides a neutron flux determination method and device applied to dating of a samarium-neodymium isotope system, and the method comprises the steps: carrying out the isotope measurement of a sample, and determining the isotope measurement data of the sample; simulating a neutron irradiation effect based on the sample, and determining neutron irradiation model data; comparing the isotope measurement data with the neutron irradiation model data to determine a comparison result; an epithermal neutron flux is determined based on the comparison result. The epithermal neutron flux is obtained through sample isotope data simulation, the application range is wide, the method can be used for well drilling samples, return samples, aerolite samples and the like, the accuracy of dating results of isotope systems with different depths is improved, and a reliable basis is provided for researching the renovation rate of well drilling lunar soil samples.

Description

Technical Field

[0001] The embodiments of this specification relate to the field of space science and technology, and in particular to a method for determining neutron flux used in dating a samarium-neodymium isotope system. Background Art

[0002] The radioactive samarium-neodymium isotope system is widely used for geological tracing and dating in geological research. Sm and Nd represent samarium and neodymium respectively. The dating results can be used to study the formation and evolution history of the Earth, the Moon and other celestial bodies in the solar system. Both samarium 147 and samarium 146 are long-lived radioactive isotopes that can produce stable neodymium 143 and neodymium 142 through alpha decay: samarium 147->neodymium 143+alpha, samarium 1476->neodymium 143+alpha. The corresponding half-lives are 106Ga(10 9 Years: 1 billion years) and 103Ma (10 6 Year: million years).

[0003] Since the half-lives of samarium-147 and samarium-146 are both over 100 million years, the samples analyzed by the samarium-neodymium isotope dating system are mostly over 1 billion years old. During such a long period of time, lunar soil samples will be exposed to long-term cosmic ray radiation, and some isotopes will drift significantly due to neutron capture.

[0004] Since the capture cross section of thermal neutrons (less than 0.4eV) and the resonance integrated cross section of epithermal neutrons (0.4eV~0.5MeV) are relatively large, the samarium-neodymium isotope system is greatly affected by thermal and epithermal neutron capture. Therefore, the correction of neutron capture effect is mainly to correct the impact of thermal and epithermal neutrons on the samarium-neodymium isotope system. The samarium-neodymium isotope drift is directly related to the thermal neutron flux and epithermal neutron flux. The thermal neutron capture cross section of samarium 149 is very large, reaching 71627 barns. When a samarium 149 atom captures a thermal neutron, it becomes samarium 150. Therefore, the samarium 150 / samarium 149 isotope ratio of lunar soil samples that have been affected by neutron radiation for a long time will change significantly. The neutron capture cross section of neodymium 143 is also relatively large, with a thermal neutron capture cross section of 335 barns and an epithermal neutron resonance capture cross section of 132 barns. Neutron capture of neodymium 143 will turn it into neodymium 144, which means that one neodymium 143 is reduced and one neodymium 144 is added, which will affect the accuracy of samarium-neodymium isotope dating.

[0005] The current estimate of epithermal neutron flux is based on the empirical value of the ratio of thermal neutron to epithermal neutron flux. However, the ratio of thermal neutron to epithermal neutron flux varies widely, so it is impossible to give an accurate epithermal neutron flux. Therefore, a better solution is urgently needed. Summary of the invention

[0006] In view of this, the embodiments of this specification provide a method for determining neutron flux applied to the dating of samarium-neodymium isotope system. One or more embodiments of this specification also relate to a neutron flux determination device applied to the dating of samarium-neodymium isotope system, a computing device, a computer-readable storage medium and a computer program to solve the technical defects existing in the prior art.

[0007] According to a first aspect of an embodiment of this specification, a method for determining neutron flux applied to dating of a samarium-neodymium isotope system is provided, comprising:

[0008] Performing isotope measurement on the sample to determine isotope measurement data of the sample;

[0009] Simulate the neutron irradiation effect based on the sample and determine the neutron irradiation model data;

[0010] Determine a comparison result based on the comparison between the isotope measurement data and the neutron irradiation model data;

[0011] The epithermal neutron flux is determined based on the comparison results.

[0012] In a possible implementation, performing isotope measurement on a sample to determine isotope measurement data of the sample includes:

[0013] Identify earth standard materials and calibrate mass spectrometers based on earth standard materials;

[0014] Performing extraction operation on samples to determine samples to be tested;

[0015] Measuring the sample to be tested by a mass spectrometer to determine the initial measurement result;

[0016] The initial measurements are corrected to determine the isotopic measurements of the sample.

[0017] In a possible implementation, neutron irradiation effect simulation is performed on a sample to determine neutron irradiation model data, including:

[0018] Determine the composition of lunar standard materials, and determine the simulation environment based on the composition of lunar standard materials;

[0019] Determine neutron flux and neutron energy spectrum;

[0020] Determine cross-section information based on simulation environment, neutron flux and neutron energy spectrum;

[0021] Neutron irradiation model data is determined based on the cross-section information.

[0022] In a possible implementation, comparing the isotope measurement data with the neutron irradiation model data to determine a comparison result includes:

[0023] Perform residual calculation based on isotope measurement data and neutron irradiation model data, and determine residual calculation results;

[0024] The comparison result is determined based on the residual calculation result and the element type.

[0025] In a possible implementation, determining the epithermal neutron flux based on the comparison result includes:

[0026] The initial epithermal neutron flux is adjusted by a least square method, and the comparison result is updated based on the initial epithermal neutron flux to obtain a target comparison result;

[0027] When the target comparison result satisfies a preset variance condition, the epithermal neutron flux is determined.

[0028] In a possible implementation, the initial epithermal neutron flux is adjusted by a least square method, including:

[0029] The initial epithermal neutron flux was adjusted using a gradient descent algorithm via the least squares method.

[0030] In one possible implementation, the earth standard materials include:

[0031] The earth standard material for strontium is SRM 987;

[0032] The earth standard material of neodymium is Ames;

[0033] The earth standard material of hafnium is JMC 475;

[0034] The lead standard material is NBS 981.

[0035] According to a second aspect of an embodiment of this specification, there is provided a neutron flux determination device for dating a samarium-neodymium isotope system, comprising:

[0036] A measurement data determination module is configured to perform isotope measurement on the sample and determine isotope measurement data of the sample;

[0037] A neutron irradiation effect module is configured to simulate the neutron irradiation effect based on the sample and determine the neutron irradiation model data;

[0038] A data comparison module is configured to compare the isotope measurement data and the neutron irradiation model data to determine a comparison result;

[0039] The neutron flux determination module is configured to determine the epithermal neutron flux based on the comparison result.

[0040] According to a third aspect of an embodiment of this specification, a computing device is provided, including:

[0041] Memory and processor;

[0042] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the above-mentioned neutron flux determination method applied to the dating of the samarium-neodymium isotope system are implemented.

[0043] According to a fourth aspect of the embodiments of this specification, a computer-readable storage medium is provided, which stores computer-executable instructions, which, when executed by a processor, implement the steps of the above-mentioned method for determining neutron flux applied to the dating of the samarium-neodymium isotope system.

[0044] According to a fifth aspect of the embodiments of this specification, a computer program is provided, wherein when the computer program is executed in a computer, the computer is caused to execute the steps of the above-mentioned method for determining neutron flux applied to dating of the samarium-neodymium isotope system.

[0045] The embodiments of this specification provide a method and device for determining neutron flux used in dating of samarium-neodymium isotope system, wherein the method for determining neutron flux used in dating of samarium-neodymium isotope system includes: performing isotope measurement on a sample to determine isotope measurement data of the sample; simulating neutron irradiation effect based on the sample to determine neutron irradiation model data; comparing the isotope measurement data and the neutron irradiation model data to determine the comparison result; and determining the epithermal neutron flux based on the comparison result. The size of the epithermal neutron flux is obtained by simulating the sample isotope data, which has a wide range of applications and can be used for drilling samples, return samples, meteorite samples, etc. It improves the accuracy of the dating results of isotope systems at different depths and provides a reliable basis for studying the renovation rate of drilling lunar soil samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of a method for determining neutron flux applied to dating of samarium-neodymium isotope system provided by one embodiment of this specification;

[0047] Figure 2 It is a schematic diagram of neutron differential flux intensity of a neutron flux determination method applied to samarium-neodymium isotope system dating provided by an embodiment of this specification;

[0048] Figure 3 It is a schematic diagram of the probability of neutrons reacting with helium-3 in a neutron flux determination method applied to the dating of samarium-neodymium isotope system provided by one embodiment of this specification;

[0049] Figure 4 It is a structural schematic diagram of a neutron flux determination device for dating a samarium-neodymium isotope system provided by an embodiment of this specification;

[0050] Figure 5It is a structural block diagram of a computing device provided by an embodiment of this specification. DETAILED DESCRIPTION

[0051] Many specific details are described in the following description to facilitate a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of this specification, so this specification is not limited to the specific implementation disclosed below.

[0052] The terms used in one or more embodiments of this specification are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of this specification. The singular forms of "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0053] It should be understood that although the terms first, second, etc. may be used to describe various information in one or more embodiments of this specification, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0054] In this specification, a method for determining neutron flux used in dating of a samarium-neodymium isotope system is provided. This specification also relates to a neutron flux determination device used in dating of a samarium-neodymium isotope system, a computing device, and a computer-readable storage medium, which are described in detail one by one in the following embodiments.

[0055] See also Figure 1 , Figure 1 A flow chart of a method for determining neutron flux applied to dating of a samarium-neodymium isotope system provided according to an embodiment of the present specification is shown, which specifically includes the following steps.

[0056] Step 101: perform isotope measurement on a sample to determine isotope measurement data of the sample.

[0057] In one possible implementation, isotope measurement is performed on a sample to determine isotope measurement data of the sample, including: determining earth standard materials and calibrating a mass spectrometer based on the earth standard materials; performing an extraction operation on the sample to determine a sample to be tested; measuring the sample to be tested by a mass spectrometer to determine an initial measurement result; and correcting the initial measurement result to determine the isotope measurement data of the sample.

[0058] Among them, the earth standard materials include: SRM 987, the earth standard material of strontium; Ames, the earth standard material of neodymium; JMC 475, the earth standard material of hafnium; and NBS 981, the earth standard material of lead. The selection of standard materials is based on the following considerations: The isotope ratio of SRM 987 has been accurately measured. Ames is an existing isotope standard material that has been measured. The isotope ratio of JMC 475 has been accurately measured and can be used to calibrate the accuracy and precision of quality control analytical instruments. NBS 981 is an existing lead isotope standard material that has been measured.

[0059] In practical applications, first, the mass spectrometer is calibrated using standard materials, including: SRM 987, the earth standard material for strontium; Ames, the earth standard material for neodymium; JMC 475, the earth standard material for hafnium; and NBS 981, the lead standard. These standard materials are used to calibrate the measurement results of mass spectrometry to ensure that the current isotope content (such as strontium, neodymium, hafnium, lead, etc.) D1 and N measurement results are correct, where D1 is the number of daughters produced by decay, and N is the current content of the decay parent. Mass spectrometers including mass spectrometers (MS-MS), inductively coupled plasma mass spectrometers (ICP-MS), etc. can be used to measure samples that have been dissolved, chemically extracted, etc., and the measurement results are processed and corrected at the same time to eliminate the influence of factors such as instrument drift or interference on the measurement results, and obtain the measurement value of the isotope composition in the sample.

[0060] For example, taking KREEP basalt sample 15386 as an example, the sample contains radioactive parent isotopes and their decay products (daughter isotopes). In order to accurately measure the isotope ratio, the sample is dissolved and chemically extracted to extract the isotope to be measured. The mass ratio of different isotopes in the sample is measured using an inductively coupled plasma mass spectrometer (ICP-MS). At the same time, the measurement results are processed and corrected to eliminate the influence of interference factors such as instrument drift on the measurement results.

[0061] The embodiment of this specification utilizes sample isotope data to simulate the size of the epithermal neutron flux, which has a wide range of applications and can be used for drilling samples, return samples, meteorite samples, etc.

[0062] Step 102: Simulate the neutron irradiation effect based on the sample to determine neutron irradiation model data.

[0063] In one possible implementation, a simulation of neutron irradiation effects is performed based on samples to determine neutron irradiation model data, including: determining the composition of lunar standard materials, and determining the simulation environment based on the composition of the lunar standard materials; determining the neutron flux and neutron energy spectrum; determining cross-section information based on the simulation environment, neutron flux and neutron energy spectrum; and determining neutron irradiation model data based on the cross-section information.

[0064] For details, see Table 1. The composition of lunar standard materials can refer to the material composition within a 2-meter depth range of the lunar soil surface:

[0065] Table 1

[0066]

[0067] In practical applications, firstly, the lunar standard material composition (for example, the material composition obtained within a depth of 2 meters on the lunar soil surface) is used to compare with the standard results (for example, the measured lunar neutron density) to verify the accuracy of obtaining neutron flux, neutron energy spectrum and nuclear reaction probability through material composition. Secondly, the neutron flux and neutron energy spectrum at different depths are determined; based on the neutron flux and neutron energy spectrum at different depths, the cross-sectional information is determined, and the number of daughters D2 generated by the neutron capture effect is calculated assuming time T; the number of daughters D1 generated by decay is calculated by the decay equation D1=N(e λT -1).

[0068] Furthermore, the neutron flux and neutron energy spectrum are obtained. Neutrons of different energies and nuclides have different modes of action. For drilling samples, the neutron energy spectra at different depths are significantly different. Based on the scattering cross sections and absorption cross sections of neutrons and nuclides of different energies and fluxes, the probability of nuclear reactions between elements and neutrons is calculated using nuclear reaction simulation software, and the concentration and composition of the elements after neutron irradiation are obtained. Among them, the nuclear reaction simulation software may include Geant4.

[0069] Using the above example, the composition of the isotope before irradiation is assumed to be consistent with that of chondrite (CHUR, chondritic uniform reservoir). Then the calculation of neutron irradiation effect is carried out, first of all, the neutron flux and neutron energy spectrum are determined. For drilling samples, there are significant differences in neutron energy spectra at different depths. The neutron differential energy spectrum of drilling at a depth of 0-10 meters is as follows Figure 2 According to the scattering cross section and absorption cross section of neutrons and nuclides, see Figure 3 , the nuclear reaction simulation software Geant4 is used to calculate the probability of nuclear reaction between elements and neutrons, and to obtain the concentration and composition of the elements after neutron irradiation.

[0070] Step 103: Compare the isotope measurement data and the neutron irradiation model data to determine a comparison result.

[0071] In a possible implementation, comparing the isotope measurement data and the neutron irradiation model data to determine the comparison result includes: performing residual calculation based on the isotope measurement data and the neutron irradiation model data to determine the residual calculation result; and determining the comparison result based on the residual calculation result and the element type.

[0072] In practical applications, the calculated isotopic composition is compared with the measured isotopic composition, the residuals of the measured values ​​are calculated, and the squares of all the residuals are summed to obtain the residual sum of squares. The residual sum of squares is divided by the number of element species used to obtain the variance of the model value and the measured value.

[0073] Continuing with the above example, after obtaining the concentration and composition of the element after neutron irradiation, the calculated isotopic composition is compared with the measured isotopic composition, and the variance of the two is calculated.

[0074] Step 104: Determine the epithermal neutron flux based on the comparison result.

[0075] In a possible implementation, determining the epithermal neutron flux based on the comparison result includes: adjusting the initial epithermal neutron flux by a least squares method, updating the comparison result based on the initial epithermal neutron flux, and obtaining a target comparison result; and determining the epithermal neutron flux when the target comparison result satisfies a preset variance condition.

[0076] In practical applications, the least squares method is used to determine the best fitting parameters of the epithermal neutron flux: the epithermal neutron flux assumption is adjusted using the least squares method, and the epithermal neutron flux is adjusted to minimize the variance between the model value and the measured value of the element composition. The epithermal neutron flux that minimizes the variance between the model value and the measured value is found, and this flux is the optimal epithermal neutron flux value, which is output.

[0077] In a possible implementation, adjusting the initial epithermal neutron flux by using a least square method includes: adjusting the initial epithermal neutron flux by using a gradient descent algorithm by using a least square method.

[0078] In practical applications, the adjustment method of epithermal neutron flux can be implemented by using optimization algorithms such as gradient descent.

[0079] Using the above example, the gradient descent optimization algorithm is used to adjust the epithermal neutron flux, and the epithermal neutron flux that minimizes the variance between the model value and the measured value is found. This flux is the optimal epithermal neutron flux value and is output. The optimal epithermal neutron flux finally obtained is 4.05×10 16 n / cm2 .

[0080] Furthermore, after determining the epithermal seed flux, an accurate dating result corrected for the neutron capture effect can be given.

[0081] Specifically, the basic formula for isotope geological age determination is:

[0082] T = (1 / λ)ln(D / N+1);

[0083] Among them, λ is the decay constant, D is the current content of decay daughter bodies, N is the current content of decay parent bodies, and T is the age, that is, the time that the geological body has experienced since the formation of a closed system.

[0084] In addition to increasing with age D1, the content of decay daughters will also be affected by neutron capture D2, D = D1 + D2. This is especially true when using the samarium-neodymium isotope dating method. Determining the thermal and epithermal neutron fluxes can correct the effects of neutron capture and improve the accuracy of samarium-neodymium isotope dating.

[0085] The embodiments of this specification use the optimal epithermal neutron flux value to obtain relatively accurate dating results of the samarium-neodymium isotope system at different depths, providing a reliable basis for studying the refurbishment rate of drilling lunar soil samples.

[0086] The embodiments of this specification provide a method and device for determining neutron flux used in dating of samarium-neodymium isotope system, wherein the method for determining neutron flux used in dating of samarium-neodymium isotope system includes: performing isotope measurement on a sample to determine isotope measurement data of the sample; simulating neutron irradiation effect based on the sample to determine neutron irradiation model data; comparing the isotope measurement data and the neutron irradiation model data to determine the comparison result; and determining the epithermal neutron flux based on the comparison result. The size of the epithermal neutron flux is obtained by simulating the sample isotope data, which has a wide range of applications and can be used for drilling samples, return samples, meteorite samples, etc. It improves the accuracy of the dating results of isotope systems at different depths and provides a reliable basis for studying the renovation rate of drilling lunar soil samples.

[0087] Corresponding to the above method embodiment, this specification also provides an embodiment of a neutron flux determination device for dating a samarium-neodymium isotope system, Figure 4 FIG. 1 is a schematic diagram showing a neutron flux determination device for dating a samarium-neodymium isotope system provided in an embodiment of the present specification. Figure 4 As shown, the device comprises:

[0088] The measurement data determination module 401 is configured to perform isotope measurement on the sample and determine isotope measurement data of the sample;

[0089] The neutron irradiation effect module 402 is configured to perform a simulation of the neutron irradiation effect based on the sample and determine the neutron irradiation model data;

[0090] A data comparison module 403 is configured to compare the isotope measurement data and the neutron irradiation model data to determine a comparison result;

[0091] The neutron flux determination module 404 is configured to determine the epithermal neutron flux based on the comparison result.

[0092] In a possible implementation, performing isotope measurement on a sample to determine isotope measurement data of the sample includes:

[0093] Identify earth standard materials and calibrate mass spectrometers based on earth standard materials;

[0094] Performing extraction operation on samples to determine samples to be tested;

[0095] Measuring the sample to be tested by a mass spectrometer to determine the initial measurement result;

[0096] The initial measurements are corrected to determine the isotopic measurements of the sample.

[0097] In a possible implementation, neutron irradiation effect simulation is performed on a sample to determine neutron irradiation model data, including:

[0098] Determine the composition of lunar standard materials, and determine the simulation environment based on the composition of lunar standard materials;

[0099] Determine neutron flux and neutron energy spectrum;

[0100] The cross-section information is determined based on the simulation environment, neutron flux and neutron energy spectrum; and the neutron irradiation model data is determined based on the cross-section information.

[0101] In a possible implementation, comparing the isotope measurement data with the neutron irradiation model data to determine a comparison result includes:

[0102] Perform residual calculation based on isotope measurement data and neutron irradiation model data, and determine residual calculation results;

[0103] The comparison result is determined based on the residual calculation result and the element type.

[0104] In a possible implementation, determining the epithermal neutron flux based on the comparison result includes:

[0105] The initial epithermal neutron flux is adjusted by a least square method, and the comparison result is updated based on the initial epithermal neutron flux to obtain a target comparison result;

[0106] When the target comparison result satisfies a preset variance condition, the epithermal neutron flux is determined.

[0107] In a possible implementation, the initial epithermal neutron flux is adjusted by a least square method, including:

[0108] The initial epithermal neutron flux was adjusted using a gradient descent algorithm via the least squares method.

[0109] In one possible implementation, the earth standard materials include:

[0110] The earth standard material for strontium is SRM 987;

[0111] The earth standard material of neodymium is Ames;

[0112] The earth standard material of hafnium is JMC 475;

[0113] The lead standard material is NBS 981.

[0114] The embodiments of this specification provide a method and device for determining neutron flux used in dating of samarium-neodymium isotope system, wherein the device for determining neutron flux used in dating of samarium-neodymium isotope system includes: performing isotope measurement on a sample to determine isotope measurement data of the sample; simulating neutron irradiation effect based on the sample to determine neutron irradiation model data; comparing the isotope measurement data with the neutron irradiation model data to determine the comparison result; and determining the epithermal neutron flux based on the comparison result. The size of the epithermal neutron flux is obtained by simulating the isotope composition of the sample, which has a wide range of applications and can be used for drilling samples, return samples, meteorite samples, etc. It improves the accuracy of the dating results of isotope systems at different depths and provides a reliable basis for studying the renovation rate of drilling lunar soil samples.

[0115] The above is a schematic scheme of a neutron flux determination device applied to samarium-neodymium isotope system dating of this embodiment. It should be noted that the technical scheme of the neutron flux determination device applied to samarium-neodymium isotope system dating and the technical scheme of the neutron flux determination method applied to samarium-neodymium isotope system dating belong to the same concept, and the details of the technical scheme of the neutron flux determination device applied to samarium-neodymium isotope system dating that are not described in detail can all be referred to the description of the technical scheme of the neutron flux determination method applied to samarium-neodymium isotope system dating.

[0116] Figure 4 The block diagram of a computing device 400 according to one embodiment of the present specification is shown. The components of the computing device 400 include but are not limited to a memory 410 and a processor 420. The processor 420 is connected to the memory 410 via a bus 430, and the database 450 is used to store data.

[0117] The computing device 400 also includes an access device 440 that enables the computing device 400 to communicate via one or more networks 460. Examples of these networks include a public switched telephone network (PSTN), a local area network (LAN), a wide area network (WAN), a personal area network (PAN), or a combination of communication networks such as the Internet. The access device 440 may include one or more of any type of network interface (e.g., a network interface card (NIC)) that is wired or wireless, such as an IEEE 802.11 wireless local area network (WLAN) wireless interface, a world-wide interoperability for microwave access (Wi-MAX) interface, an Ethernet interface, a universal serial bus (USB) interface, a cellular network interface, a Bluetooth interface, and a near field communication (NFC).

[0118] In one embodiment of the present specification, the above components of the computing device 400 and Figure 4 Other components not shown in the figure may also be connected to each other, for example, via a bus. It should be understood that Figure 4 The computing device structure block diagram shown is only for the purpose of illustration, and is not intended to limit the scope of this specification. Those skilled in the art can add or replace other components as needed.

[0119] The computing device 400 may be any type of stationary or mobile computing device, including a mobile computer or mobile computing device (e.g., a tablet computer, a personal digital assistant, a laptop computer, a notebook computer, a netbook, etc.), a mobile phone (e.g., a smart phone), a wearable computing device (e.g., a smart watch, smart glasses, etc.), or other types of mobile devices, or a stationary computing device such as a desktop computer or a personal computer (PC). The computing device 400 may also be a mobile or stationary server.

[0120] Among them, the processor 420 is used to execute the following computer executable instructions, which, when executed by the processor, implement the steps of the above-mentioned method for determining the neutron flux applied to the dating of the samarium-neodymium isotope system. The above is a schematic scheme of a computing device of this embodiment. It should be noted that the technical scheme of the computing device and the above-mentioned method for determining the neutron flux applied to the dating of the samarium-neodymium isotope system belong to the same concept. The details of the technical scheme of the computing device that are not described in detail can all be found in the description of the technical scheme of the method for determining the neutron flux applied to the dating of the samarium-neodymium isotope system.

[0121] An embodiment of the present specification also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the above-mentioned method for determining neutron flux applied to the dating of the samarium-neodymium isotope system.

[0122] The above is a schematic scheme of a computer-readable storage medium of this embodiment. It should be noted that the technical scheme of the storage medium and the technical scheme of the neutron flux determination method applied to the dating of the samarium-neodymium isotope system are of the same concept, and the details not described in detail in the technical scheme of the storage medium can be found in the description of the technical scheme of the neutron flux determination method applied to the dating of the samarium-neodymium isotope system.

[0123] An embodiment of the present specification also provides a computer program, wherein when the computer program is executed in a computer, the computer is caused to execute the steps of the above-mentioned neutron flux determination method applied to the dating of the samarium-neodymium isotope system.

[0124] The above is a schematic scheme of a computer program of this embodiment. It should be noted that the technical scheme of the computer program and the technical scheme of the neutron flux determination method applied to the dating of the samarium-neodymium isotope system are of the same concept, and the details not described in detail in the technical scheme of the computer program can be found in the description of the technical scheme of the neutron flux determination method applied to the dating of the samarium-neodymium isotope system.

[0125] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0126] The computer instructions include computer program codes, which may be in source code form, object code form, executable files or some intermediate forms, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0127] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of this specification are not limited by the order of the actions described, because according to the embodiments of this specification, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the embodiments of this specification.

[0128] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0129] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the embodiments of this specification, so that technicians in the relevant technical field can well understand and use this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A method for determining neutron flux used in dating the samarium-neodymium isotope system, characterized in that: include: Performing isotope measurement on the sample to determine isotope measurement data of the sample; Simulating neutron irradiation effects on the sample to determine neutron irradiation model data; Determine a comparison result based on the comparison between the isotope measurement data and the neutron irradiation model data; An epithermal neutron flux is determined based on the comparison.

2. The method according to claim 1, characterized in that The isotope measurement of the sample to determine the isotope measurement data of the sample includes: determining earth standard materials, and calibrating a mass spectrometer based on the earth standard materials; Performing an extraction operation on the sample to determine a sample to be tested; Measuring the sample to be tested by the mass spectrometer to determine an initial measurement result; The initial measurement result is corrected to determine the isotopic measurement data of the sample.

3. The method according to claim 1, characterized in that The simulating of neutron irradiation effect based on the sample to determine neutron irradiation model data includes: Determining the composition of lunar standard materials, and determining the simulation environment based on the composition of the lunar standard materials; Determine neutron flux and neutron energy spectrum; Determining cross-section information based on the simulation environment, the neutron flux and the neutron energy spectrum; Neutron irradiation model data is determined based on the cross-section information.

4. The method according to claim 1, characterized in that: The step of comparing the isotope measurement data with the neutron irradiation model data to determine a comparison result includes: Perform residual calculation based on the isotope measurement data and the neutron irradiation model data, and determine a residual calculation result; A comparison result is determined based on the residual calculation result and the element type.

5. The method according to claim 1, characterized in that The determining of the epithermal neutron flux based on the comparison result comprises: adjusting the initial epithermal neutron flux by a least square method, and updating the comparison result based on the initial epithermal neutron flux to obtain a target comparison result; In a case where the target comparison result satisfies a preset variance condition, the epithermal neutron flux is determined.

6. The method according to claim 5, characterized in that The method of adjusting the initial epithermal neutron flux by the least square method comprises: The initial epithermal neutron flux was adjusted using a gradient descent algorithm via the least squares method.

7. The method according to claim 2, characterized in that The earth standard materials include: The earth standard material for strontium is SRM 987; The earth standard material of neodymium is Ames; The earth standard material of hafnium is JMC 475; The lead standard material is NBS 981.

8. A neutron flux determination device for dating samarium-neodymium isotope system, characterized in that: include: A measurement data determination module is configured to perform isotope measurement on a sample and determine isotope measurement data of the sample; A neutron irradiation effect module is configured to simulate the neutron irradiation effect based on the sample and determine neutron irradiation model data; A data comparison module is configured to compare the isotope measurement data and the neutron irradiation model data to determine a comparison result; The neutron flux determination module is configured to determine the epithermal neutron flux based on the comparison result.

9. A computing device, characterized in that include: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the neutron flux determination method applied to the dating of the samarium-neodymium isotope system as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for determining neutron flux applied to the dating of a samarium-neodymium isotope system as claimed in any one of claims 1 to 7.

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