Neutron coincidence measuring instrument with passive absolute scale function

Abstract

The invention provides a radioactive substance content measuring method and device and a neutron coincidence measuring device, and relates to the technical field of nuclear measurement. The method comprises the following steps: establishing a geometric model of a measurement object according to the appearance of the measurement object with a to-be-measured radioactive substance attached in a predetermined area; obtaining relative position information of a geometric model of the measurement object and a measurement model comprising the simulated neutron detector, obtaining material information corresponding to the measurement object, and associating the material information to the geometric model; according to the information of the simulated measurement object, obtaining a detection result of a simulated neutron detector simulated based on a generalized semi-Markov process simulation method on neutrons generated by simulated radioactive substance fission; and obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive substance and the detection result, and measuring the content of the radioactive substance to be measured by using a measurement device corresponding to the measurement model according to the calibration coefficient. The method improves the accuracy of radioactive substance content measurement.

Description

Technical Field

[0001] The present disclosure relates to the field of nuclear measurement technology, and in particular to a neutron coincidence measuring instrument with a passive absolute calibration function. Background Art

[0002] Nuclear fuel is an important regulatory object in the field of nuclear safeguards. It is particularly important to quickly and accurately measure the total amount of radioactive substances in nuclear materials. For fissionable nuclides such as uranium and plutonium, the relevant technology measures and counts the fission neutrons emitted by fissionable materials to calculate the total amount of radioactive substances. How to improve the accuracy of measuring the content of radioactive substances has become an urgent problem to be solved.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method and device for measuring the content of radioactive substances and a neutron coincidence measurement device, so as to improve the accuracy of the measurement of the content of radioactive substances at least to a certain extent.

[0005] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by the practice of the present disclosure.

[0006] According to one aspect of the present disclosure, a method for measuring the content of radioactive material is provided, comprising: establishing a geometric model of the measurement object according to its appearance, wherein a predetermined area of ​​the measurement object is attached with a radioactive material to be measured; obtaining relative position information between the geometric model of the measurement object and the measurement model, wherein the measurement model comprises a simulated neutron detector; obtaining material information corresponding to the measurement object and associating it with the geometric model to obtain information of a simulated measurement object corresponding to the measurement object, wherein the information of the simulated measurement object comprises properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and a simulated position of the simulated radioactive material to be measured in the simulated measurement object corresponding to the predetermined area; obtaining detection results of neutrons generated by fission of the simulated radioactive material by the simulated neutron detector simulated based on a generalized semi-Markov process simulation method according to the information of the simulated measurement object; obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured according to the calibration coefficient using a measurement device corresponding to the measurement model.

[0007] According to one embodiment of the present disclosure, the measurement model also includes a simulated neutron source; according to the information of the simulated measurement object, the detection result of the simulated neutron detector for the neutrons produced by the fission of the simulated radioactive material is obtained based on the information of the simulated measurement object, including: simulating the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time based on the generalized semi-Markov process simulation method, the information of the state of the system includes the position and velocity of the neutrons in the system, the state of the system is related to the events that may occur in the system, and the events that may occur in the system include the simulated neutron source neutron emission event, the delayed neutron precursor nuclear decay event and the neutron collision event; according to the state of the system, the detection result of the simulated neutron detector for the neutrons produced by the fission of the simulated radioactive material is obtained.

[0008] According to an embodiment of the present disclosure, a generalized semi-Markov process simulation method is used to simulate the change of the state of a system composed of the simulated neutron source and the simulated measurement object over time, including: obtaining a set of events that may occur in the system according to information about the simulated neutron source and information about the simulated measurement object, the set of events that may occur in the system including information about events that may occur in the system, and the events that may occur in the system including a first event; obtaining a set of states of the system according to information about the simulated neutron source, information about the simulated measurement object, and information about events that may occur in the system, the set of states of the system including information about multiple states of the system, and the multiple states including a first state and a second state; obtaining state transition time information according to information about events that may occur in the system and information about multiple states of the system, the state transition time information including a time interval for the system to transition from the first state to the second state when the first event occurs; and obtaining the state of the system at a target time according to the state transition time information.

[0009] According to one embodiment of the present disclosure, the information of the neutron collision event includes the fission amount per unit time of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, wherein: the fission amount per unit time is obtained based on the neutron flux of the simulated neutron source reaching the simulated radioactive material per unit volume, the simulated mass of the simulated radioactive material and the reaction cross section of the energy spectrum of the simulated neutron source for the induced fission of the simulated radioactive material.

[0010] According to one embodiment of the present disclosure, the information of the neutron collision event also includes the fission neutron intensity produced by the neutrons emitted by the simulated neutron source and induced by the fission of the simulated radioactive material per unit volume, wherein: the fission neutron intensity is obtained based on the fission amount per unit time and the number of neutrons produced per fission, and the number of neutrons produced per fission follows Terrel distribution.

[0011] According to one embodiment of the present disclosure, the information of the neutron collision event also includes the leakage intensity of fission neutrons produced by the fission of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, wherein: the leakage intensity of the fission neutrons is obtained based on the fission neutron intensity and the absorption probability of the simulated measurement object.

[0012] According to an embodiment of the present disclosure, the detection result of the simulated neutron detector for neutrons produced by the simulated neutron source inducing fission of the simulated radioactive material is obtained according to the state of the system, including: simulating the simulated neutron detector to measure the neutrons produced by the simulated neutron source inducing fission of the simulated radioactive material using the coincidence method to obtain a simulated coincidence count rate.

[0013] According to one embodiment of the present disclosure, the calibration coefficient of the measurement object is obtained according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, including: fitting a target linear function using the simulated mass of the simulated radioactive material and the simulated coincidence count rate, and obtaining the parameters of the target linear function as the calibration coefficient, wherein the variables of the target linear function include the mass of the radioactive material and the coincidence count rate of the neutron detector.

[0014] According to one embodiment of the present disclosure, a geometric model of the measured object is established based on the appearance of the measured object, including: using laser three-dimensional scanning technology to obtain a cloud point map of the outer envelope of the measured object, and establishing the geometric model of the measured object based on the cloud point map, or, using CAD modeling technology to establish the geometric model of the measured object.

[0015] According to another aspect of the present disclosure, a device for measuring the content of radioactive substances is provided, comprising: a geometric modeling module, for establishing a geometric model of the measured object according to its appearance, wherein a predetermined area of ​​the measured object is attached with a radioactive substance to be measured; a first acquisition module, for acquiring relative position information between the geometric model of the measured object and the measurement model, wherein the measurement model comprises a simulated neutron detector; a second acquisition module, for acquiring material information corresponding to the measured object and associating it with the geometric model, so as to obtain information of a simulated measured object corresponding to the measured object, wherein the information of the simulated measured object comprises properties of basic constituent substances, properties and simulated mass of simulated radioactive substances, and a simulated position of the simulated radioactive substance to be measured in the simulated measured object corresponding to the predetermined area; a simulation measurement module, for obtaining, according to the information of the simulated measurement object, a detection result of the simulated neutron detector simulated based on a generalized semi-Markov process simulation method for neutrons generated by fission of the simulated radioactive substance; and an acquisition module, for obtaining a calibration coefficient of the measured object according to the simulated mass of the simulated radioactive substance and the detection result of the simulated neutron detector, so as to measure the content of the radioactive substance to be measured according to the calibration coefficient using a measurement device corresponding to the measurement model.

[0016] According to another aspect of the present disclosure, there is provided a neutron coincidence measurement device, comprising: a detector body, the detector body comprising a sample cavity and a neutron detector, the sample cavity being used to place a measurement object comprising a radioactive material to be measured, and the neutron detector being used to detect neutrons produced by fission of the radioactive material to be measured; an electronic circuit connected to the neutron detector, for receiving and processing the detection counts of the neutron detector and outputting a corresponding signal; calibration coefficient acquisition software, for implementing any of the above methods to obtain the calibration coefficient of the measurement object; and measurement software, for obtaining the content of the radioactive material to be measured based on the output signal of the electronic circuit and the calibration coefficient of the measurement object.

[0017] According to another aspect of the present disclosure, an electronic device is provided, comprising: a memory, a processor, and executable instructions stored in the memory and executable in the processor, wherein the processor implements any of the above methods when executing the executable instructions.

[0018] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which computer-executable instructions are stored, and when the executable instructions are executed by a processor, any of the above methods is implemented.

[0019] The embodiments of the present disclosure provide a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the above-mentioned various optional implementations.

[0020] The embodiment of the present disclosure provides a method for measuring the content of radioactive substances. A geometric model of the measuring object is established according to the appearance of the measuring object with the radioactive substances to be measured attached in a predetermined area, and the relative position information between the geometric model of the measuring object and the measuring model including a simulated neutron detector is obtained. The material information corresponding to the measuring object is obtained and associated with the geometric model to obtain information corresponding to the measuring object, including the properties of the basic constituent substances, the properties and simulated mass of the simulated radioactive substances, and the information of the simulated measuring object at a simulated position corresponding to the predetermined area of ​​the simulated measuring object. Then, according to the information of the simulated measuring object, the detection result of the simulated neutron detector simulated based on the generalized semi-Markov process simulation method for the neutrons generated by the fission of the simulated radioactive substance is obtained. Then, according to the simulated mass of the simulated radioactive substance and the detection result of the simulated neutron detector, a calibration coefficient of the measuring object is obtained. According to the calibration coefficient, the content of the radioactive substance to be measured can be measured using a measuring device corresponding to the measurement model, thereby improving the accuracy of the measurement of the content of the radioactive substance.

[0021] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings.

[0023] Figure 1A The main structural schematic diagram of the neutron coincidence measurement device is shown.

[0024] Figure 1B A cross-sectional view of a detector body of a neutron coincidence measurement device is shown as an example.

[0025] Figure 1C A schematic diagram of the arrangement of a neutron detector in a detector body is shown as an example.

[0026] Figure 2 A flow chart of a method for measuring radioactive material content in an embodiment of the present disclosure is shown.

[0027] Figure 3 Shows Figure 2 FIG. 5 is a schematic diagram of the processing process of step S202 in one embodiment.

[0028] Figure 4 Shows Figure 2 FIG. 5 is a schematic diagram of the processing process of step S208 in one embodiment.

[0029] Figure 5 Shows Figure 4 FIG. 4 is a schematic diagram of the processing process of step S402 in one embodiment.

[0030] Figure 6 A block diagram of a radioactive material content measuring device in an embodiment of the present disclosure is shown.

[0031] Figure 7 A schematic structural diagram of an electronic device in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The accompanying drawings are only schematic illustrations of the disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0033] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, devices, steps, etc. may be adopted. In other cases, well-known structures, methods, devices, implementations or operations are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0034] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. The symbol " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0035] In this disclosure, unless otherwise clearly specified and limited, terms such as "connection" should be understood in a broad sense, for example, it can be an electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0036] In the process of nuclear reaction, there are many events that are correlated in time. Such correlated events usually reflect the inherent motion laws of the nucleus. The coincidence method is a method to study these correlated events. Some radionuclides have a very low spontaneous fission neutron rate, but can undergo fission reactions after absorbing neutrons, especially thermal neutron reactions with a larger cross section. In the related technology, an external neutron source is used to irradiate the measurement object, inducing the fission of the radioactive material in the measurement object, emitting two or more fission neutrons with time correlation, and then the coincidence method is used to measure the fission neutrons, so as to calculate the content of the radioactive material.

[0037] Some neutron coincidence measurement devices in related technologies establish a functional relationship between the radioactive material mass of the standard sample and the induced fission neutron coincidence count rate, and then infer the unknown uranium mass. However, in actual applications, the shapes of the measurement objects are different, and the contents of the basic components are also different. It is difficult to prepare one-to-one corresponding standard samples for relative calibration, resulting in large errors when using standard samples for calibration, thereby reducing the accuracy of the neutron coincidence measurement device in measuring the content of radioactive materials.

[0038] Therefore, the present disclosure provides a method for measuring the content of radioactive material, which simulates the detection of neutrons produced by the fission of radioactive material on a simulated measurement object modeled according to the measurement object by simulating a neutron source based on a generalized semi-Markov process simulation method, and absolutely calibrates the measurement object according to the mass of the simulated radioactive material and the simulated detection result to obtain a calibration coefficient, so as to measure the content of the radioactive material to be measured using a measuring device corresponding to the measurement model according to the calibration coefficient, thereby improving the accuracy of the calibration and thus improving the accuracy of the measurement of the content of the radioactive material.

[0039] Figures 1A to 1C An exemplary neutron coincidence measurement device to which the radioactive material content measurement method of the present disclosure can be applied is shown. Figure 1A The main structural diagram of the neutron coincidence measurement device is shown in FIG. Figure 1A As shown, the neutron coincidence measurement device 10 may include a detector cart 102, a detector body 104, and electronic equipment 106. The detector body 104 may be placed on the bottom plate of the detector cart 102, and wheels may be provided under the bottom plate of the detector cart 102 to facilitate the movement of the detector cart 102. The detector body 104 may be provided with a neutron source, a sample chamber, a neutron detector, etc. (for example, see Figure 1B), neutron detectors can be used with electronic circuits ( Figures 1A to 1C The electronic circuit is used to receive the detection count of the neutron detector and process it, and output the corresponding signal, which can be connected to the electronic device 106 through a wired or wireless communication link or an optical fiber cable. The electronic device 106 can be various electronic devices with a display screen and supporting input and output, including but not limited to smart phones, tablet computers, laptops, desktop computers, wearable devices, virtual reality devices, smart homes, etc. The electronic device 106 can be a device with data processing capabilities itself, and can also be connected to a server with data processing capabilities through a network to realize data processing functions through the server.

[0040] The radioactive material content measurement method disclosed in the present invention can be implemented in the form of calibration coefficient acquisition software. The neutron coincidence measurement device 10 applies the software to obtain the calibration coefficient during measurement, so that the neutron coincidence measurement device is used as a neutron coincidence measurement instrument with a passive absolute calibration function. For example, the calibration coefficient acquisition software can be operated on the electronic device 106 to obtain the calibration coefficient of the measurement object. The electronic device 106 can also run measurement software for obtaining the content of the radioactive material to be measured in the measurement object placed in the detector body 104 according to the output signal of the electronic circuit and the calibration coefficient of the measurement object.

[0041] Figure 1B A cross-sectional view of a detector body of a neutron coincidence measurement device is shown as an example. Figure 1B The detector body shown in FIG. 1 can be applied to Figure 1A The neutron coincidence measurement device shown in FIG. Figure 1B As shown, a neutron source 1042 , a sample cavity 1044 and a neutron detector 1046 may be disposed in the detector body. A reflective layer 1048 may be disposed inside the sample cavity 1044 , and the neutron detector 1046 may be disposed in the moderator 10410 .

[0042] Neutron source 1042 can be selected as an induced neutron source, such as a (α, n) source. The emitted neutrons are single neutrons, which can avoid interference with the neutron coincidence count rate. For example, an americium-lithium (Am-Li) source, an americium-beryllium (Am-Be) source, etc. can be selected. Sample cavity 1044 can be used to place a measurement object including a radioactive substance to be measured. For example, it can be a stainless steel-cadmium sleeve of a certain thickness, and a nickel reflective layer (corresponding to reflective layer 1048) of a certain thickness can be coated inside. Reflective layer 1048 can make neutron radiation more penetrating and at the same time make statistical accuracy higher.

[0043] Neutron detectors 1046 may be arranged radially around the sample cavity 1044 (for example, see Figure 1CThe neutron detector 1046 can be arranged in layers. 3 The radial direction of the He counter tube may be the same as the radial direction of the sample chamber 1044 . Figure 1C The following is a schematic diagram showing the arrangement of a neutron detector in a detector body. Figure 1C In the experiment, neutron detector 1046 is used as 3 For example, the He counter tube 3 He counter tubes are evenly arranged in two layers in the moderator 10410. The moderator 10410 can be polyethylene, for example. 3 The outer layer of the He counter tube (not shown in the figure) can be provided with a cadmium sleeve. The design of the moderator 10410 and the cadmium sleeve can maximize the detection efficiency of induced fission neutrons, while reducing the detection efficiency of (α, n) reaction neutrons of the neutron source 1042 to suppress background neutrons, reduce the indoor low-energy neutron background count rate, and improve the shielding effect between the neutron detector 1046 and the neutron source 1042.

[0044] In some embodiments, for some radionuclides with a high spontaneous fission neutron rate, the neutron coincidence measurement device 10 can also be used for detection in a passive mode, that is, the neutron source 1042 therein is taken out, and the neutron detector 1046 detects the neutrons generated by the fission of the radioactive material to be measured on the measurement object placed in the sample cavity 1044. In this case, the calibration coefficient acquisition software can also be set to a passive mode, and the measurement model used in its simulation process also corresponds to a passive mode.

[0045] The embodiments of the present disclosure are described by taking the active mode (i.e., detecting neutrons generated by fission of the radioactive material to be detected induced by a neutron source) as an example, but are not limited thereto.

[0046] It should be understood that Figures 1A to 1C The structure of the neutron coincidence measurement device shown in the figure is only schematic. According to the implementation requirements, various parts of the neutron coincidence measurement device can be appropriately adjusted.

[0047] Figure 2 FIG. 1 is a flow chart showing a method for measuring radioactive material content according to an exemplary embodiment. Figure 2 The method shown can be applied to the neutron coincidence measurement device 10 , for example, and implemented by the electronic device 106 .

[0048] refer to Figure 2 , the method 20 provided in the embodiment of the present disclosure may include the following steps.

[0049] In step S202, a geometric model of the measurement object is established according to the appearance of the measurement object, and a radioactive substance to be measured is attached to a predetermined area of ​​the measurement object.

[0050] In some embodiments, the measurement object may be an object contaminated with nuclear materials, such as an object contaminated with nuclear materials on a certain surface or in a certain area of ​​the surface. The contaminated nuclear materials contain radioactive substances to be measured, such as fissile materials such as uranium and plutonium.

[0051] In some embodiments, the principle of laser ranging can be used to scan the measurement object to establish a geometric model of the measurement object. For example, see Figure 3 .

[0052] In other embodiments, CAD modeling technology can be used to establish a geometric model of the measured object. For example, some original object models can be scanned and input into a computer system, or some existing three-dimensional models can be used as models of basic graphics required for modeling. The basic graphics can be, for example, cubes, cones, cylinders, spheres, etc. Then, various part models can be generated by performing intersection, union, and difference operations on the basic graphics to achieve the modeling function.

[0053] In some embodiments, the user can set the location of the "contaminant" of the geometric model of the measurement object through a visual interface according to the area on the surface of the measurement object contaminated with nuclear materials (i.e., the predetermined area) (i.e., the simulated position of the simulated radioactive material to be measured in the simulated measurement object corresponding to the predetermined area), and the contaminant is the part that is subsequently set as the radioactive material to be measured. For example, if the entire surface of a geometric body is a specified contaminant, the coating function can be used to achieve it. For another example, if a certain face or several faces of a simple regular geometric body (such as a cube in a basic graphic, etc.) are used to generate a contaminant according to a specified thickness, the difference set operation and intersection set operation of the geometric body can be used to achieve it. For another example, if a contaminant of a specified thickness is set in a certain part of the surface of a complex irregular geometric body, the surface triangle picking mode can be used, that is, by selecting a set of triangles in the surface area of ​​the object, a certain area on the surface of the object is set as a contaminant.

[0054] In step S204, relative position information between the geometric model of the measurement object and the measurement model is obtained, where the measurement model includes a simulated neutron detector.

[0055] In some embodiments, a simulation can be performed based on the neutron source, neutron detector, sample cavity, etc. in the neutron coincidence measurement device to establish a simulation measurement model. In the measurement model, the relative relationship of the size and position of the simulated neutron source, simulated neutron detector, simulated sample cavity, etc. can be designed according to the actual device.

[0056] In some embodiments, the user can set the relative position relationship between the geometric model of the measurement object and the measurement model through the visual interface according to the position of the measurement object in the neutron coincidence measurement device. The geometric model of the measurement object can be scaled, rotated, translated, mirrored, merged, split, copied, and other graphic operations can be performed on the visual interface according to actual needs.

[0057] In step S206, material information corresponding to the measurement object is obtained and associated with the geometric model to obtain information of the simulated measurement object corresponding to the measurement object, the information of the simulated measurement object includes properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and simulated position of the simulated radioactive material to be measured in the simulated measurement object corresponding to a predetermined area.

[0058] In some embodiments, the user can set the properties of the basic components of the simulated measurement object and the properties of the simulated radioactive material through a visual interface according to the actual conditions of the measurement object and the radioactive material to be measured, for example, basic properties such as material density can be included. The material name corresponding to the density can also be set and saved in the database for subsequent use.

[0059] In some embodiments, for the same measurement object, multiple different simulation masses may be set for simulation respectively to obtain multiple corresponding detection results, so as to obtain the calibration coefficient of the measurement object by fitting the multiple simulation masses with the corresponding detection results.

[0060] In step S208, the detection result of the simulated neutron detector simulated based on the generalized semi-Markov process simulation method for neutrons generated by fission of simulated radioactive materials is obtained according to the information of the simulated measurement object.

[0061] In some embodiments, the life process of each neutron in the detector system can be simulated according to the information of the simulated neutron source, the simulated neutron detector, and the simulated measurement object, so that the exemplary embodiment can refer to Figure 4 and Figure 5 .

[0062] In step S210, a calibration coefficient of the measurement object is obtained according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured using a measuring device corresponding to the measurement model according to the calibration coefficient.

[0063] In some embodiments, the neutron coincidence measurement device may use the coincidence method to process the counts of the neutron detector, and use the coincidence count rate of the neutron to characterize the number of fissions. The simulated mass and the simulated coincidence count rate of the simulated radioactive material may be used to fit the target linear function, and the parameters of the target linear function (for example, the slope of the linear function) may be obtained as calibration coefficients, wherein the variables of the target linear function may be the mass of the radioactive material and the coincidence count rate of the neutron detector. Then, the content of the radioactive material to be measured on the measurement object may be inferred based on the coincidence count rate measured by the neutron coincidence measurement device and the calibration coefficient obtained by fitting.

[0064] According to the method for measuring the content of radioactive substances provided by the embodiment of the present disclosure, a geometric model of the measuring object is established according to the appearance of the measuring object with the radioactive substances to be measured attached in a predetermined area, and the relative position information between the geometric model of the measuring object and the measuring model including the simulated neutron detector is obtained; the material information corresponding to the measuring object is obtained and associated with the geometric model, so as to obtain the information corresponding to the measuring object, including the properties of the basic constituent substances, the properties and simulated mass of the simulated radioactive substances, and the simulated information of the measuring object at the simulated position corresponding to the predetermined area of ​​the simulated measuring object; then, according to the information of the simulated measuring object, the detection result of the simulated neutron detector simulated based on the generalized semi-Markov process simulation method for the neutrons generated by the fission of the simulated radioactive substances is obtained; then, according to the simulated mass of the simulated radioactive substances and the detection result of the simulated neutron detector, the calibration coefficient of the measuring object is obtained; and according to the calibration coefficient, the content of the radioactive substances to be measured is measured using the measuring device corresponding to the measurement model. Compared with the method of relative calibration using a standard sample with a low degree of similarity to the actual object to be measured, the absolute calibration method provided by the embodiment of the present disclosure can obtain a calibration coefficient that is more matched with the object to be measured and more accurate, thereby improving the accuracy of the measurement of the content of radioactive substances.

[0065] Figure 3 Shows Figure 2 The processing diagram of step S202 in one embodiment is shown in FIG. Figure 3 As shown, in the embodiment of the present disclosure, the above step S202 may further include the following steps.

[0066] Step S302: using laser three-dimensional scanning technology to obtain a cloud point diagram of the outer envelope of the measurement object.

[0067] Step S304: establishing a geometric model of the measurement object according to the cloud point map.

[0068] In some embodiments, the principle of laser ranging can be used to perform three-dimensional laser scanning on the measurement object to obtain a cloud point map of the outer envelope of the measurement object. The scanned measurement object is then approximated with a cube grid based on the cloud point map to establish a geometric model of the measurement object, so as to carry out neutron transport simulation calculations based on the cube grid (also called "voxel grid") with material properties set.

[0069] According to the method provided in the embodiment of the present disclosure, a geometric model of the measurement object is established after obtaining a cloud point diagram of the outer envelope of the measurement object through laser three-dimensional scanning, thereby enabling direct visual modeling of samples of arbitrary shapes, and eliminating the need to solve high-order equations when simulating the migration free path sampling (finding the intersection of the ray track and the interface) in neutron transport calculations, thereby effectively improving the speed of simulation calculations.

[0070] Figure 4 Shows Figure 2 The processing process of step S208 in one embodiment is shown in FIG. Figure 4 As shown, in the embodiment of the present disclosure, the above step S208 may further include the following steps.

[0071] Step S402, based on the generalized semi-Markov process simulation method, simulates the change of the state of a system composed of a simulated neutron source and a simulated measurement object over time, wherein the information of the state of the system includes the position and velocity of neutrons in the system, and the state of the system is related to events that may occur in the system, and events that may occur in the system include neutron emission events of simulated neutron source, delayed neutron precursor nuclear decay events and neutron collision events.

[0072] In some embodiments, the state transition time information can be obtained based on the information of possible events in the system and the information of multiple states of the system, and then the state of the system at the target time can be obtained based on the state transition time information. For example, the exemplary implementation method can refer to Figure 5 .

[0073] In some embodiments, information on neutron collision events may include the amount of fission per unit time of fission per unit volume of simulated radioactive material induced by neutrons emitted by a simulated neutron source, wherein the amount of fission per unit time may be obtained based on the neutron flux of the simulated neutron source reaching a unit volume of simulated radioactive material, the simulated mass of the simulated radioactive material, and the reaction cross section of the energy spectrum of the simulated neutron source for induced fission of the simulated radioactive material.

[0074] Based on Figures 1A to 1C Taking the measurement model simulated by the neutron coincidence measurement device shown in FIG. 1 as an example, if the activity of two neutron sources (Am-Li) symmetrically placed above and below is Fn, the neutron flux of the two sources at the voxel (i, j, k) of the measurement object at the same time can be calculated by the following formula (1):

[0075]

[0076] The relative position of the upper source 1 is (P x1 ,P y1 ,P z1 ), the relative position of the lower source 2 is (P x2 ,P y2 ,P z2 ), the distances of voxel (i,j,k) from the two sources are:

[0077] Dis_1 2 =(P x1 -i) 2 +(P y1 -i) 2 +(P z1 -i) 2 (2)

[0078] Dis_2 2 =(P x2 -i) 2 +(P y2 -i) 2 +(P z2 -i) 2 (3)

[0079] If the mass of the fissile nuclide (corresponding to the radioactive material to be measured) at voxel (i, j, k) is M X The macroscopic cross section of the neutron source energy spectrum for the induced fission of this nuclide is σ Fission , then the number of fissions that occur in voxel (i,j,k) per second is:

[0080] Fiss_cout i,j,k =Φ i,j,k ·M X ·σ Fission (4)

[0081] In some embodiments, information on neutron collision events may also include fission neutron intensity produced by neutrons emitted by a simulated neutron source and induced fission of simulated radioactive material per unit volume, wherein the fission neutron intensity is obtained based on the amount of fission per unit time and the number of neutrons produced per fission, and the number of neutrons produced per fission follows a Terrel distribution.

[0082] Still based on Figures 1A to 1C Taking the measurement model of the neutron coincidence measurement device as an example, the total amount of 4-pi fission neutrons N generated by voxel (i, j, k) per second is i,j,k It can be obtained from Terr distribution:

[0083] N i,j,k=Terrel(Fiss_cout i,j,k ) (5)

[0084] In some embodiments, the information of neutron collision events also includes the leakage intensity of fission neutrons produced by the fission of simulated radioactive materials per unit volume induced by neutrons emitted by the simulated neutron source, wherein the leakage intensity of the fission neutrons is obtained based on the fission neutron intensity and the absorption probability of the simulated measurement object.

[0085] Depending on the position of the voxel (i, j, k) of the measured object, the fission neutron may be absorbed by the measured object and cannot be measured by the detector. For example, the secondary neutrons generated near the edge of the measured object are easier to be measured by the detector than the neutrons generated inside the measured object. The absorption probability P corresponding to the voxels (i, j, k) at different positions can be estimated by Monte Carlo simulation based on the three-dimensional voxel structure. Ab(i,j,k) , then the intensity of the fission neutrons leaking from the measured object from the voxel (i, j, k) is:

[0086] N i,j,k_leak =(1-P Ab(i,j,k) )N i,j,k (6)

[0087] Step S404, obtaining detection results of the simulated neutron detector for neutrons generated by the simulated neutron source-induced fission of simulated radioactive materials according to the state of the system.

[0088] In some embodiments, the simulated neutron detector can be simulated to measure neutrons produced by fission of simulated radioactive materials induced by a simulated neutron source using the coincidence method to obtain a simulated coincidence count rate, and the simulated coincidence count rate can be fitted with the simulated mass to obtain a calibration coefficient.

[0089] Figure 5 Shows Figure 4 The processing process of step S402 in one embodiment is shown in FIG. Figure 5 As shown, in the embodiment of the present disclosure, the above step S402 may further include the following steps.

[0090] Step S502, obtaining a set of possible events in the system according to information of a simulated neutron source and information of a simulated measurement object, wherein the set of possible events in the system includes information of possible events in the system, and the possible events in the system include a first event.

[0091] Step S504, obtaining a system state set according to information of a simulated neutron source, information of a simulated measurement object and information of events that may occur in the system, wherein the system state set includes information of multiple states of the system, and the multiple states include a first state and a second state.

[0092] Step S506, obtaining state transition time information based on information about events that may occur in the system and information about multiple states of the system, wherein the state transition time information includes a time interval for the system to transition from a first state to a second state when a first event occurs.

[0093] Step S508, obtaining the state of the system at the target time according to the state transfer time information.

[0094] In the system, there are N s Neutron sources (e.g. Figures 1A to 1C The device in the figure has two neutron sources), and N f Taking the fissile nuclides as an example, suppose that the delayed neutron precursor nuclides produced by the fission of each fissionable nuclide can be divided into 6 groups, and s is a value of the state variable. Then the set S of the system state is:

[0095]

[0096] in, Represents the state value of the neutron in the i-th system, i=1,...,N p . and Represent the position and velocity of the neutron in the i-th system, i=1,...,N p , N p is the total number of neutrons in the system. s,i is the current state value of the i-th neutron source, i=1,...,N s . Generally, q s,i is the intensity of the i-th neutron source, i=1,...,N s When N p =0,N d =0,q s,i (i=1,…,N s )=0, let s=0.

[0097] The set A of possible events in the system is: A = {[the i-th neutron source emits a neutron, i = 1, ..., N s ]; [The ith neutron collides with the target nucleus, i = 1, ..., N p ];}; Let α be the value of an event, and the possible values ​​of α are N s +N p , possible state transition time vector C s N s +N p dimension.

[0098] Let E(s) be the set of possible events in state s, E(s)∈A, if N p and q s,i(i=1,...,N s ) are both greater than zero, then E(s)=A.

[0099] Suppose P(s′; s, α) is the probability distribution of event α occurring in state s; state transition occurs at time t0, and the emission intensity of the neutron from the i-th source is q s,i ,i=1,...,N s ; The macroscopic cross section of the i-th neutron at time t0 is ∑ t,i , then its collision rate is v i ∑ t,i ,i=1,…,N p . Then P(s′; s, α) obeys the following discrete distribution:

[0100]

[0101] in:

[0102]

[0103] Assume {F α ,α∈A} is the distribution set of system state transition time intervals.

[0104] The time interval Δt of the ith neutron source emitting source particles follows the distribution:

[0105]

[0106] The time interval Δt of the i-th delayed neutron precursor nuclear decay follows the distribution:

[0107]

[0108] Since the collision rate of neutrons in the i-th system is v i ∑ t,i ,i=1,…,N p , then the collision time interval of neutrons in the i-th system follows the following distribution:

[0109]

[0110] Set {f α ,α∈A} has N s +N d +N p elements.

[0111] Then the distribution of system state transfer time interval is:

[0112]

[0113] For s∈S, define C s is the possible state transition time in state s, Cs ={(c(α),α∈A:c(α)≥0,andc(α)>0 only ifα∈ε(s)}. Since A is a finite set, we can determine a sequence C with A-dimensional vectors s =(c(α),α∈A),C s is a subset of the A-dimensional Euclidean space. For s∈S and c∈C s ,make

[0114] t * (s,c)=min{c(α):α∈ε(s)} (14)

[0115] t * (s,c) represents the time when the next event occurs under state s and state transition vector c. Let the elements of set A be arranged in a certain way, let

[0116] α * (s,c)=min{α:c(α)=t * (s,c)} (15)

[0117] Then α * is the event that triggers the system to transition out of state s because it has the shortest retention time in this state.

[0118] For s, s'∈S and A∈A, the set of newly added events N(s'; s, α) and the set of events left over from the old events O(s'; s, α) are defined according to the following formula:

[0119] N(s′;s,α)=ε(s′)\(ε(s)-{α}) (16)

[0120] O(s′;s,α)=ε(s′)∩(ε(s)-{α}) (17)

[0121] When event α triggers the transition of the system from state s to state s', new clocks need to be set for the events in the set N(s'; s, α); the clocks of the events in the set O(s'; s, α) continue to run. The clocks of the events in the set ε(s)\O(s'; s, α) are interrupted and set to 0, and the corresponding events will no longer be the possible next events. For example, the event that occurs corresponds to the collision between the system neutron and the target nuclide, which results in the production of n fission neutrons. The new event refers to the event that may occur in the next state transition of the newly produced neutrons, and the old events include all source neutron emission neutron events, various delayed neutron precursor nuclear decay events, and the next possible event of the neutrons that did not collide.

[0122] Now, we can define a discrete-time Markov process GSMP{(Yn ,c n ),n≥0}, where Y n is the nth state of GSMP, c n is the time vector of the next state transition after the nth state transition. This process has the following state space

[0123]

[0124] For the following forms

[0125] B={s′}×{c′∈C s′ :c′(α)≤x(α),α∈ε(s′)} (19)

[0126] For some fixed real numbers (x(α), α∈A) (x(a) means that c(a) is bounded), the transition probability from (s,c) to B is:

[0127] P((s,c),B)=p(s′;s,α * )∏ α∈N F α (x(α))∏ α∈O I{c(α)-t * ≤x(α)} (20)

[0128] where t * =t * (s,c),α * =α * (s,c), N=N(s′;s,α * ), O=O(s′;s,α * ). I{·} is the indicator function. When · satisfies, I{·}=1, otherwise it is 0. (Note: For O, I{c(α)-t * ≤x(α)} all satisfy)

[0129] Thus, we can define a continuous-time GSMP as a state in which n The length of time is t * (Y n ,c n ) is a piecewise constant process. More precisely, let τ0 = 0, and

[0130]

[0131] Then τ n is the update point of the nth state transition. Similarly, let

[0132] N(t)=sup{n≥0:τ n ≤t} (22)

[0133] For finite t, assume that N(t) is finite. Then with {(Y n ,c n )} associated GSMPZ t Defined as:

[0134] Z t =Y N(t) (twenty three)

[0135] That is Z t is the state of GSMP at time t.

[0136] The generalized semi-Markov process can be used to simulate and solve the main equation of stochastic neutron dynamics. First, a non-interruption condition (C1) is introduced: for any s, s′∈S, α∈A, if α∈ε(s) and p(s; s′, α)>0, then

[0137] For any GSMP{Z t ,t≥0}, record the following additional sample path features:

[0138] τ n , the update point of the nth state transition; α n , the nth event; Y n , the nth state reached by the generalized semi-Markov process; c n , the state transition time interval vector after the nth state transition occurs; c n (α) is the value from τ n The time interval from the moment until α occurs; given the initial state Y0 of GSMP, let τ0 = 0 and repeat the following recursive formula:

[0139] τ n+1 =τ n +t * (Y n ,c n ) (twenty four)

[0140] α n+1 =α * (Y n ,c n ) (25)

[0141] Y n+1 =φ(Y n ,α n+1 ) (26)

[0142] Where φ(.,.,.) is the mapping from state s to s' when event α occurs for the kth time in state s.

[0143] In the simulation of the generalized semi-Markov process of the transient evolution of the energy-space correlated neutron random field, for the state transition time interval t * (Y n ,c n ), sampling can be done using direct simulation or quasi-simulation methods.

[0144] For each state transition, the state transition interval is adjusted by: setting a new clock for all new events; for all old events, subtracting the time remaining on the old clock from the time of the last transition to the present. Therefore, if α∈ε(Y n ) and α≠α n+1 , α∈ε(Y n+1 ),but

[0145] c n+1 (α) = c n (α)-t * (Y n ,c n ); (27)

[0146] If α∈ε(Y n+1 )and Or α=α n+1 ,but

[0147] c n+1 (α)=X(α,N(α,n+1)+1) (28)

[0148] From the above recursive algorithm, Z is obtained from Y. In particular, if t * (Y n ,c n )>0, then in the interval [τ n ,τ n+1 ],Z t =Y n .

[0149] According to the method provided in the embodiment of the present disclosure, by simulating the change of the state of a system composed of a simulated neutron source and a simulated measurement object over time based on a generalized semi-Markov process simulation method, state transition time information is obtained according to information about events that may occur in the system and information about multiple states of the system, and then the state of the system at a target moment is obtained according to the state transition time information. This can realize the simulation of the lifetime process of neutrons in the system, improve the accuracy of the neutron coincidence count of the simulated measurement of the system, and thus improve the accuracy of the calibration coefficient of the measurement object.

[0150] Figure 6 FIG. 1 is a block diagram of a device for measuring radioactive material content according to an exemplary embodiment. Figure 6The device shown can be used, for example, in the electronic device 106 of the neutron coincidence measurement device 10 .

[0151] refer to Figure 6 The device 60 provided in the embodiment of the present disclosure may include a geometric modeling module 602 , a first acquisition module 604 , a second acquisition module 606 , a simulation measurement module 608 and an acquisition module 610 .

[0152] The geometric modeling module 602 may be used to establish a geometric model of the measurement object according to the appearance of the measurement object, wherein a predetermined area of ​​the measurement object is attached with radioactive material to be measured.

[0153] The geometric modeling module 602 can also be used to obtain a cloud point map of the outer envelope of the measurement object using laser three-dimensional scanning technology, and establish a geometric model of the measurement object based on the cloud point map, or establish a geometric model of the measurement object using CAD modeling technology.

[0154] The first acquisition module 604 can be used to acquire relative position information between a geometric model of the measurement object and a measurement model, where the measurement model may include a simulated neutron source and a simulated neutron detector.

[0155] The second acquisition module 606 can be used to acquire material information corresponding to the measurement object and associate it with the geometric model to obtain information of a simulated measurement object corresponding to the measurement object, wherein the information of the simulated measurement object includes properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and a simulated position of the simulated radioactive material to be measured in the simulated measurement object corresponding to a predetermined area.

[0156] The simulation measurement module 608 can be used to obtain detection results of neutrons produced by fission of simulated radioactive materials induced by a simulated neutron source by a simulated neutron detector simulated based on a generalized semi-Markov process simulation method according to information of the simulated measurement object.

[0157] The simulation measurement module 608 can also be used to simulate the change of the state of a system composed of a simulated neutron source and a simulated measurement object over time based on a generalized semi-Markov process simulation method. The information of the system state includes the position and velocity of neutrons in the system. The system state is related to events that may occur in the system. Events that may occur in the system include neutron emission events of simulated neutron source, delayed neutron precursor nuclear decay events and neutron collision events; according to the state of the system, the detection results of the simulated neutron detector for neutrons produced by the fission of simulated radioactive materials induced by the simulated neutron source are obtained.

[0158] The simulation measurement module 608 can also be used to obtain a set of events that may occur in the system based on the information of the simulated neutron source and the information of the simulated measurement object, the set of events that may occur in the system includes information about events that may occur in the system, and the events that may occur in the system include a first event; obtain a set of system states based on the information of the simulated neutron source, the information of the simulated measurement object, and the information about events that may occur in the system, the set of system states includes information about multiple states of the system, and the multiple states include a first state and a second state; obtain state transition time information based on the information about events that may occur in the system and the information about multiple states of the system, the state transition time information includes the time interval for the system to transition from a first state to a second state when the first event occurs; and obtain the state of the system at a target time based on the state transition time information.

[0159] The information of neutron collision events may include the fission amount per unit time of the fission of unit volume of simulated radioactive material induced by neutrons emitted by the simulated neutron source, wherein: the fission amount per unit time is obtained based on the neutron flux of the simulated neutron source reaching the unit volume of simulated radioactive material, the simulated mass of the simulated radioactive material and the reaction cross section of the energy spectrum of the simulated neutron source for the induced fission of the simulated radioactive material.

[0160] The information of neutron collision events may also include fission neutron intensity produced by neutrons emitted by a simulated neutron source and induced by fission of simulated radioactive material per unit volume, wherein: the fission neutron intensity is obtained based on the fission amount per unit time and the number of neutrons produced per fission, and the number of neutrons produced per fission follows Terrel distribution.

[0161] The information of neutron collision events may also include leakage intensity of fission neutrons produced by fission of simulated radioactive material per unit volume induced by neutrons emitted by a simulated neutron source, wherein the leakage intensity of fission neutrons is obtained based on the fission neutron intensity and the absorption probability of the simulated measurement object.

[0162] The simulation measurement module 608 can also be used to simulate the simulated neutron detector to measure the neutrons produced by the fission of simulated radioactive materials induced by the simulated neutron source using the coincidence method to obtain a simulated coincidence count rate.

[0163] The acquisition module 610 can be used to obtain the calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured using the measurement device corresponding to the measurement model according to the calibration coefficient.

[0164] The acquisition module 610 can also be used to fit the target linear function using the simulated mass and simulated coincidence count rate of the simulated radioactive material, and the parameters of the target linear function are obtained as calibration coefficients. The variables of the target linear function include the mass of the radioactive material and the coincidence count rate of the neutron detector.

[0165] The specific implementation of each module in the device provided by the embodiment of the present disclosure can refer to the content of the above method, which will not be repeated here.

[0166] Figure 7 The following is a schematic diagram showing the structure of an electronic device in an embodiment of the present disclosure. It should be noted that: Figure 7 The device shown is only an example of a computer system, which should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0167] like Figure 7 As shown, the device 700 includes a central processing unit (CPU) 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a storage portion 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the device 700 are also stored. The CPU 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0168] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, a mouse, etc.; an output section 707 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN card, a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 710 as needed, so that a computer program read therefrom is installed into the storage section 708 as needed.

[0169] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication part 709, and / or installed from a removable medium 711. When the computer program is executed by a central processing unit (CPU) 701, the above-mentioned functions defined in the system of the present disclosure are executed.

[0170] It should be noted that the computer-readable medium shown in the present disclosure may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0171] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0172] The modules involved in the embodiments described in the present disclosure may be implemented by software or by hardware. The modules described may also be set in a processor, for example, it may be described as: a processor includes a data acquisition module, a data preprocessing module, a recurrent network module, a convolutional network module, a data integration module and a state classification module. The names of these modules do not constitute a limitation on the modules themselves in some cases. For example, the data acquisition module may also be described as a "module for obtaining initial data from the connected server side."

[0173] As another aspect, the present disclosure further provides a computer-readable medium, which may be included in the device described in the above embodiment; or may exist independently without being assembled into the device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by a device, the device is used to implement:

[0174] A geometric model of the measurement object is established according to its appearance, wherein a predetermined area of ​​the measurement object is attached with a radioactive material to be measured; relative position information between the geometric model of the measurement object and the measurement model is obtained, wherein the measurement model includes a simulated neutron detector; material information corresponding to the measurement object is obtained and associated with the geometric model to obtain information of the simulated measurement object corresponding to the measurement object, wherein the information of the simulated measurement object includes properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and a simulated position of the simulated radioactive material to be measured in the simulated measurement object corresponding to the predetermined area; detection results of neutrons generated by fission of simulated radioactive materials by a simulated neutron detector simulated based on a generalized semi-Markov process simulation method are obtained according to the information of the simulated measurement object; a calibration coefficient of the measurement object is obtained according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured according to the calibration coefficient using a measuring device corresponding to the measurement model.

[0175] The embodiments of the present disclosure provide a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the above-mentioned various optional implementations.

[0176] The exemplary embodiments of the present disclosure are specifically shown and described above. It should be understood that the present disclosure is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A method for measuring the content of radioactive substances, characterized in that: include: Establishing a geometric model of the measurement object according to the appearance of the measurement object, wherein a predetermined area of ​​the measurement object is attached with a radioactive material to be measured; Acquiring relative position information between a geometric model of the measurement object and a measurement model, wherein the measurement model includes a simulated neutron detector; Acquiring material information corresponding to the measurement object and associating it with a geometric model to obtain information of a simulated measurement object corresponding to the measurement object, wherein the information of the simulated measurement object includes properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and a simulated position of the simulated radioactive material to be measured on the simulated measurement object corresponding to the predetermined area; Obtaining, according to the information of the simulated measurement object, a detection result of the simulated neutron detector simulated based on the generalized semi-Markov process simulation method for neutrons generated by fission of the simulated radioactive material; The calibration coefficient of the measurement object is obtained according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured according to the calibration coefficient using a measuring device corresponding to the measurement model.

2. The method according to claim 1, characterized in that The measurement model also includes a simulated neutron source; Obtaining detection results of neutrons generated by fission of the simulated radioactive material by the simulated neutron detector simulated based on the generalized semi-Markov process simulation method according to the information of the simulated measurement object, including: Based on the generalized semi-Markov process simulation method, the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time is simulated, the information of the state of the system includes the position and velocity of the neutrons in the system, the state of the system is related to the events that may occur in the system, and the events that may occur in the system include the simulated neutron source emitting neutron events, delayed neutron precursor nuclear decay events and neutron collision events; The detection result of the simulated neutron detector on neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source is obtained according to the state of the system.

3. The method according to claim 2, characterized in that The method of simulating the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time based on the generalized semi-Markov process simulation method includes: Obtaining a set of events that may occur in the system according to the information of the simulated neutron source and the information of the simulated measurement object, wherein the set of events that may occur in the system includes information of events that may occur in the system, and the events that may occur in the system include a first event; Obtaining a state set of the system according to information of the simulated neutron source, information of the simulated measurement object, and information of events that may occur in the system, wherein the state set of the system includes information of multiple states of the system, and the multiple states include a first state and a second state; Obtaining state transition time information according to information about events that may occur in the system and information about a plurality of states of the system, wherein the state transition time information includes a time interval for the system to transition from the first state to the second state when the first event occurs; The state of the system at the target time is obtained according to the state transfer time information.

4. The method according to claim 3, characterized in that The information of the neutron collision event includes the fission amount per unit time of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, wherein: The fission amount per unit time is obtained based on the neutron flux of the simulated neutron source reaching a unit volume of the simulated radioactive material, the simulated mass of the simulated radioactive material and the reaction cross section of the energy spectrum of the simulated neutron source for induced fission of the simulated radioactive material.

5. The method according to claim 4, characterized in that The information of the neutron collision event also includes the fission neutron intensity of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, wherein: The fission neutron intensity is obtained according to the fission amount per unit time and the number of neutrons produced in each fission, and the number of neutrons produced in each fission obeys Terrel distribution.

6. The method according to claim 5, characterized in that The information of the neutron collision event also includes the leakage intensity of fission neutrons produced by the fission of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, wherein: The fission neutron leakage intensity is obtained according to the fission neutron intensity and the absorption probability of the simulated measurement object.

7. The method according to any one of claims 2 to 6, characterized in that Obtaining, according to the state of the system, a detection result of the simulated neutron detector for neutrons generated by fission of the simulated radioactive material induced by the simulated neutron source, comprising: The simulated neutron detector is simulated to measure neutrons generated by fission of the simulated radioactive material induced by the simulated neutron source using a coincidence method to obtain a simulated coincidence count rate.

8. The method according to claim 7, characterized in that Obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector includes: The target linear function is fitted using the simulated mass of the simulated radioactive material and the simulated coincidence count rate, and the parameters of the target linear function are obtained as the calibration coefficients. The variables of the target linear function include the mass of the radioactive material and the coincidence count rate of the neutron detector.

9. The method according to any one of claims 2 to 5, characterized in that Establishing a geometric model of the measured object according to the appearance of the measured object includes: Using laser three-dimensional scanning technology to obtain a cloud point map of the outer envelope of the measurement object, and establishing a geometric model of the measurement object based on the cloud point map, or, The geometric model of the measured object is established using CAD modeling technology.

10. A device for measuring radioactive substance content, characterized in that: include: A geometric modeling module, used to establish a geometric model of the measurement object according to the appearance of the measurement object, wherein a predetermined area of ​​the measurement object is attached with a radioactive material to be measured; A first acquisition module, used to acquire relative position information between a geometric model of the measurement object and a measurement model, wherein the measurement model includes a simulated neutron detector; A second acquisition module is used to acquire material information corresponding to the measurement object and associate it with a geometric model to obtain information of a simulated measurement object corresponding to the measurement object, wherein the information of the simulated measurement object includes properties of basic constituent materials, properties and simulated mass of simulated radioactive materials, and a simulated position of the simulated radioactive material to be measured on the simulated measurement object corresponding to the predetermined area; A simulation measurement module, used for obtaining, according to the information of the simulated measurement object, a detection result of the simulated neutron detector simulated based on the generalized semi-Markov process simulation method for the neutrons generated by the fission of the simulated radioactive material; An acquisition module is used to obtain a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, so as to measure the content of the radioactive material to be measured according to the calibration coefficient using a measurement device corresponding to the measurement model.

11. A neutron coincidence measurement device, characterized in that: include: A detector body, the detector body comprising a sample cavity and a neutron detector, the sample cavity being used to place a measurement object including a radioactive material to be measured, and the neutron detector being used to detect neutrons generated by fission of the radioactive material to be measured; An electronic circuit connected to the neutron detector, used to receive and process the detection count of the neutron detector and output a corresponding signal; Calibration coefficient acquisition software, used to implement the method according to any one of claims 1 to 9 to obtain the calibration coefficient of the measurement object; The measuring software is used to obtain the content of the radioactive substance to be measured according to the output signal of the electronic circuit and the calibration coefficient of the measured object.

12. An electronic device comprising: A memory, a processor, and executable instructions stored in the memory and executable in the processor, wherein the processor implements the method according to any one of claims 1 to 9 when executing the executable instructions.

13. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the executable instructions are executed by a processor, the method according to any one of claims 1 to 9 is implemented.

14. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the method according to any one of claims 1 to 9 is implemented.

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