Neutron coincidence measuring instrument with passive absolute calibration function

Abstract

The present disclosure provides a method and apparatus for measuring the content of radioactive substances and a neutron coincidence measurement apparatus, relating to the field of nuclear measurement technologies. The method includes: establishing a geometric model of a measurement object according to the appearance of the measurement object with radioactive substances to be measured in a predetermined area; obtaining the relative position information between the geometric model of the measurement object and a measurement model including simulated neutron detectors, obtaining material information corresponding to the measurement object and associating it with the geometric model; obtaining the detection result of the simulated neutron detectors for the neutrons generated by the fission of the simulated radioactive substances based on the simulated measurement object information by using the generalized semi-Markov process simulation method; obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive substances and the detection result, so as to measure the content of the radioactive substances to be measured by using a measurement apparatus corresponding to the measurement model according to the calibration coefficient. This method improves the accuracy of measuring the content of radioactive substances.

Description

Technical Field

[0001] The present disclosure relates to the field of nuclear measurement technologies, and more particularly, 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, in related technologies, the total amount of radioactive substances is calculated by measuring and counting the fission neutrons emitted by the fission of fissionable materials. 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 the background art section is only used to enhance the understanding of the background of the present disclosure, and thus it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] An object of the present disclosure is to provide a method and device for measuring the content of radioactive substances, and a neutron coincidence measuring device, which can at least to some extent improve the accuracy of measuring the content of radioactive substances.

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

[0006] According to one aspect of the present disclosure, there is provided a method for measuring the content of radioactive substances, including: establishing a geometric model of a measurement object according to the appearance of the measurement object, where a predetermined area of the measurement object is attached with a radioactive substance to be measured; obtaining relative position information between the geometric model of the measurement object and a measurement model, where the measurement model includes 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, where the information of the simulated measurement object includes attributes of basic constituent substances, attributes and simulated mass of a simulated radioactive substance, and a simulated position of the simulated radioactive substance to be measured corresponding to the predetermined area in the simulated measurement object; obtaining a detection result of the simulated neutron detector for neutrons generated by fission of the simulated radioactive substance by simulating using 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 substance and the detection result of the simulated neutron detector, so as to measure the content of the radioactive substance to be measured by using a measurement device corresponding to the measurement model according to the calibration coefficient.

[0007] According to an embodiment of the present disclosure, the measurement model further includes a simulated neutron source; obtaining the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance based on the simulated method of the generalized semi-Markov process according to 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 simulated method of the generalized semi-Markov process, where the information of the state of the system includes the position and velocity of 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 event of the simulated neutron source emitting neutrons, the event of the decay of delayed neutron precursors, and the event of neutrons colliding; obtaining the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance according to the state of the system.

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

[0009] According to an embodiment of the present disclosure, the information of the neutron collision event includes the number of fissions per unit time of the simulated radioactive substance induced by the neutrons emitted by the simulated neutron source per unit volume, where: the number of fissions per unit time is obtained according to the neutron flux of the simulated neutron source reaching the simulated radioactive substance per unit volume, the simulated mass of the simulated radioactive substance, and the reaction cross-section of the simulated neutron source spectrum for the induced fission of the simulated radioactive substance.

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

[0011] According to an embodiment of the present disclosure, the information on the neutron collision event further includes the leakage intensity of the fission neutrons generated by the fission of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, where: 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, obtaining the detection result of the neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source based on the state of the system includes: simulating the use of the coincidence method by the simulated neutron detector to measure the neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source to obtain the simulated coincidence counting rate.

[0013] According to an embodiment of the present disclosure, obtaining the calibration coefficient of the measurement object based on the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector includes: fitting a target linear function using the simulated mass of the simulated radioactive material and the simulated coincidence counting rate to obtain the parameters of the target linear function as the calibration coefficient, where the variables of the target linear function include the mass of the radioactive material and the coincidence counting rate of the neutron detector.

[0014] According to an embodiment of the present disclosure, establishing the geometric model of the measurement object based on the appearance of the measurement object includes: obtaining the cloud point map of the envelope of the measurement object using laser three-dimensional scanning technology and establishing the geometric model of the measurement object based on the cloud point map, or establishing the geometric model of the measurement object using CAD modeling technology.

[0015] According to another aspect of the present disclosure, there is provided a radioactive substance content measuring device, including: a geometric modeling module configured 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 substance to be measured; a first acquisition module configured to acquire relative position information between the geometric model of the measurement object and a measurement model, the measurement model including a simulated neutron detector; a second acquisition module configured 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, the information of the simulated measurement object including attributes of basic constituent substances, attributes and simulated mass of a simulated radioactive substance, and a simulated position of the simulated radioactive substance to be measured in the simulated measurement object corresponding to the predetermined area; a simulated measurement module configured to obtain, according to the information of the simulated measurement object, a detection result of the simulated neutron detector for neutrons generated by fission of the simulated radioactive substance based on a generalized semi-Markov process simulation method; an acquisition module configured to obtain a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive substance and the detection result of the simulated neutron detector, and measure the content of the radioactive substance to be measured according to the calibration coefficient by using a measuring device corresponding to the measurement model.

[0016] According to another aspect of the present disclosure, there is provided a neutron coincidence measuring device, including: a detector main body, the detector main body including a sample chamber and a neutron detector, the sample chamber being configured to place a measurement object including a radioactive substance to be measured, the neutron detector being configured to detect neutrons generated by fission of the radioactive substance to be measured; an electronics circuit connected to the neutron detector, configured to receive detection counts of the neutron detector and process them to output corresponding signals; a calibration coefficient acquisition software configured to implement any of the above methods to obtain a calibration coefficient of the measurement object; a measurement software configured to obtain the content of the radioactive substance to be measured according to the output signal of the electronics circuit and the calibration coefficient of the measurement object.

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

[0018] According to another aspect of the present disclosure, there is provided a computer-readable storage medium, 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] 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 various alternative implementations.

[0020] The radioactive substance content measurement method provided by the embodiments of the present disclosure includes: establishing a geometric model of a measurement object according to the appearance of the measurement object with a radioactive substance to be measured in a predetermined area, obtaining relative position information between the geometric model of the measurement object and a measurement model including a simulated neutron detector, obtaining material information corresponding to the measurement object and associating it with the geometric model, so as to obtain information of the measurement object corresponding to the measurement object, including attributes of basic constituent substances, attributes of simulated radioactive substances and simulated mass, and simulated positions of simulated radioactive substances to be measured corresponding to the predetermined area in the simulated measurement object, then obtaining detection results of the simulated neutron detector for neutrons generated by fission of the simulated radioactive substance based on a generalized semi-Markov process simulation method, and then obtaining a calibration coefficient of the measurement object according to the simulated mass of the simulated radioactive substance and the detection results of the simulated neutron detector, so as to measure the content of the radioactive substance to be measured by using a measurement device corresponding to the measurement model according to the calibration coefficient, which can improve the accuracy of radioactive substance content measurement.

[0021] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By referring to the accompanying drawings and describing its exemplary embodiments in detail, the above and other objectives, features and advantages of the present disclosure will become more apparent.

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

[0024] Figure 1B An exemplary cross-sectional view of a detector body of a neutron coincidence measurement device is shown.

[0025] Figure 1C An exemplary layout schematic diagram of a neutron detector in the detector body is shown.

[0026] Figure 2 The flowchart of a radioactive substance content measurement method in an embodiment of the present disclosure is shown.

[0027] Figure 3 Shows Figure 2 The schematic diagram of the processing procedure of step S202 shown in in an embodiment.

[0028] Figure 4 shows Figure 2 a schematic diagram of the processing procedure of step S208 shown in [a certain context] in an embodiment.

[0029] Figure 5 shows Figure 4 a schematic diagram of the processing procedure of step S402 shown in [a certain context] in an embodiment.

[0030] Figure 6 shows a block diagram of a radioactive substance content measuring device in an embodiment of the present disclosure.

[0031] Figure 7 shows a schematic structural diagram of an electronic device in an embodiment of the present disclosure. Detailed implementation manners

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

[0033] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will realize that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, devices, steps, etc. can be adopted. In other cases, well-known structures, methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring the aspects of the present disclosure.

[0034] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined. The symbol " / " generally indicates that the related objects before and after are in an "or" relationship.

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

[0036] During the nuclear reaction process, there are many events that are temporally correlated. Such correlated events usually reflect the inherent motion laws of atomic nuclei. The coincidence method is a method for studying these correlated events. Some radionuclides have a very low spontaneous fission neutron rate, but can undergo fission reactions after absorbing neutrons, especially the thermal neutron reaction cross-section is larger. In the related art, an external neutron source is used to irradiate the measurement object to induce fission of the radioactive material in the measurement object, releasing two or more fission neutrons with temporal correlation, and then the coincidence method is used to measure the fission neutrons, thereby calculating the content of the radioactive material.

[0037] Some neutron coincidence measurement devices in the related art establish a functional relationship between the mass of the radioactive substance in the standard sample and the induced fission neutron coincidence counting rate, and then inversely deduce the unknown uranium mass. However, in actual applications, the shapes of the measurement objects are various, and the contents of the basic constituent substances are also different. It is difficult to prepare corresponding standard samples for relative calibration, resulting in large errors when calibrating using standard samples, thereby reducing the accuracy of the neutron coincidence measurement device for measuring the content of radioactive substances.

[0038] Therefore, the present disclosure provides a method for measuring the content of radioactive substances. By simulating the neutrons generated by the fission of radioactive substances on the simulated measurement object modeled according to the measurement object based on the generalized semi-Markov process simulation method, and obtaining the calibration coefficient by absolutely calibrating the measurement object according to the simulated mass of the radioactive substance and the simulated detection result, the content of the radioactive substance to be measured can be measured by using the measurement device corresponding to the measurement model according to the calibration coefficient, which can improve the accuracy of calibration, thereby improving the accuracy of measuring the content of radioactive substances.

[0039] Figures 1A to 1C An exemplary neutron coincidence measurement device to which the method for measuring the content of radioactive substances of the present disclosure can be applied is shown. Figure 1A The main structural schematic diagram of the neutron coincidence measurement device is shown. As Figure 1A shown, the neutron coincidence measurement device 10 may include a detector trolley 102, a detector main body 104, and an electronic device 106. The detector main body 104 can be placed on the bottom plate of the detector trolley 102. Wheels can be provided below the bottom plate of the detector trolley 102 to facilitate moving the detector trolley 102. The detector main body 104 may be provided with a neutron source, a sample chamber, neutron detectors, etc. (for example, refer to Figure 1B), the neutron detector can be connected to an electronics circuit ( Figures 1A to 1C not shown in the figure). The electronics circuit is used to receive the detection counts of the neutron detector and process them, outputting corresponding signals, and it can be connected to the electronic device 106 through wired, wireless communication links, fiber optic cables, etc. The electronic device 106 can be various electronic devices with a display screen and supporting input and output, including but not limited to smartphones, tablets, laptop computers, desktop computers, wearable devices, virtual reality devices, smart homes, etc. The electronic device 106 can be a device with its own data processing capabilities, or it can be connected to a server with data processing capabilities through a network to implement data processing functions through the server.

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

[0041] Figure 1B An exemplary cross-sectional view of the detector main body of a neutron coincidence measurement device is shown. Figure 1B The detector main body shown in the figure can be applied to, for example, Figure 1A the neutron coincidence measurement device shown in the figure. As Figure 1B shown, a neutron source 1042, a sample cavity 1044, and a neutron detector 1046 can be provided in the detector main body. A reflector layer 1048 can be provided inside the sample cavity 1044, and the neutron detector 1046 can be provided in the moderator 10410.

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

[0043] Neutron detectors 1046 can be arranged radially around the sample cavity 1044 (for example, refer to Figure 1Cis arranged to detect neutrons generated by the fission of the radioactive substance to be measured on the measurement object induced by the neutron source 1042. The neutron detector 1046 can be, for example, a 3 He counter tube, and its radial direction can be the same as the radial direction of the sample cavity 1044. Figure 1C Exemplarily shows a schematic diagram of the arrangement of a neutron detector in the detector body. In Figure 1C , taking the neutron detector 1046 as 3 He counter tube as an example, multiple 3 He counter tubes are evenly arranged in two layers in the moderator 10410. The moderator 10410 can be, for example, polyethylene. Inside the detector well, 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 neutrons from the (α, n) reaction 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 radioactive nuclides with a relatively high spontaneous fission neutron rate, the neutron coincidence measurement device 10 can also be used for detection in the passive mode, that is, the neutron source 1042 therein can be taken out, and the neutron detector 1046 detects the neutrons generated by the fission of the radioactive substance to be measured placed on the measurement object in the sample cavity 1044. In this case, the calibration coefficient acquisition software can also be set to the passive mode, and the measurement model used in its simulation process also corresponds to the passive mode.

[0045] The embodiments of the present disclosure are all described by taking the active mode (that is, detecting neutrons generated by the fission of the radioactive substance to be measured induced by the 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

[0047] Figure 2 is only schematic. According to the implementation requirements, each part in the neutron coincidence measurement device can be appropriately adjusted. Figure 2 is a flowchart of a method for measuring the content of radioactive substances shown according to an exemplary embodiment. As

[0048] shown, the method can be applied to the neutron coincidence measurement device 10, for example, and implemented by the electronic device 106. Figure 2 Referring to

[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 material, such as an object contaminated with nuclear material on a certain surface or in a certain area of the surface. The contaminated nuclear material contains the radioactive substance to be measured, and the radioactive substance to be measured may be, for example, fissionable substances 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 an exemplary implementation manner, reference can be made to Figure 3 .

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

[0053] In some embodiments, the user can, according to the area of the surface of the measurement object contaminated with nuclear material (i.e., the predetermined area), set the location of the "contaminated body" of the geometric model of the measurement object through the visualization interface (i.e., simulate the position of the radioactive substance to be measured at the simulated position corresponding to the predetermined area of the simulated measurement object). This contaminated body is the part that will be subsequently set as the radioactive substance to be measured. For example, if the entire surface of a geometric body is designated as the contaminated body, the coating function can be used to achieve this. Another example is that if a certain surface or several surfaces of a simple regular geometric body (such as a cube in the basic graphics, etc.) are generated into a contaminated body with a specified thickness, the difference set operation and intersection operation of the geometric body can be used to achieve this. Still another example is that if a contaminated body with a specified thickness is set locally on the surface of a complex irregular geometric body, the pick surface triangle mode can be used, that is, by selecting the triangle set of the surface area of the object, a certain area of the object surface can be set as the contaminated body.

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

[0055] In some embodiments, simulation can be performed according to the neutron source, neutron detector, sample chamber, etc. in the neutron coincidence measurement device to establish a simulated measurement model. In the measurement model, the relative relationships of the sizes and positions of the structures such as the simulated neutron source, simulated neutron detector, and simulated sample chamber can be designed according to the actual device.

[0056] In some embodiments, the user can set the relative positional relationship between the geometric model and the measurement model of the measurement object through a visualization interface according to the position where the measurement object is placed in the neutron coincidence measurement device. Graphic operations such as scaling, rotating, translating, mirroring, merging, splitting, and copying the geometric model of the measurement object can be performed on the visualization interface according to actual needs.

[0057] In step S206, obtain the material information corresponding to the measurement object and associate it with the geometric model to obtain the information of the simulated measurement object corresponding to the measurement object. The information of the simulated measurement object includes the attributes of the basic constituent substances, the attributes and simulated mass of the simulated radioactive substances, and the simulated positions of the simulated radioactive substances to be measured corresponding to the predetermined regions in the simulated measurement object.

[0058] In some embodiments, the user can set the attributes of the basic constituent substances and the attributes of the simulated radioactive substances of the simulated measurement object through a visualization interface according to the actual conditions of the measurement object and the radioactive substances to be measured. For example, it can include basic attributes such as material density. 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 simulated masses can be set for simulation respectively to obtain multiple corresponding detection results, so as to use the multiple simulated masses and the corresponding detection results for fitting to obtain the calibration coefficient of the measurement object.

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

[0061] In some embodiments, according to the information of the simulated neutron source, the simulated neutron detector, and the simulated measurement object, the lifetime process of each neutron in the detector system can be simulated. Thus, exemplary embodiments can be referred to Figure 4 and Figure 5 。

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

[0063] In some embodiments, the coincidence method can be used to process the counts of the neutron detectors in the neutron coincidence measurement device, and the number of fissions is characterized by the coincidence count rate of neutrons. The parameters of the target linear function (for example, the slope of the linear function) can be obtained by fitting the target linear function with the simulated mass of the simulated radioactive substance and the simulated coincidence count rate, and the calibration coefficient is obtained. Here, the variables of the target linear function can be the mass of the radioactive substance and the coincidence count rate of the neutron detector. Then, according to the coincidence count rate measured by the neutron coincidence measurement device and the calibration coefficient obtained by fitting, the content of the radioactive substance to be measured on the measurement object can be inversely deduced.

[0064] According to the radioactive substance content measurement method provided by the embodiments of the present disclosure, by establishing a geometric model of the measurement object based on the appearance of the measurement object with the radioactive substance to be measured in a predetermined area, obtaining the relative position information between the geometric model of the measurement object and the measurement model including the simulated neutron detector, obtaining the material information corresponding to the measurement object and associating it with the geometric model, so as to obtain the information of the simulated measurement object corresponding to the measurement object, including the attributes of the basic constituent substances, the attributes and simulated mass of the simulated radioactive substance, and the simulated position corresponding to the predetermined area of the simulated measurement object where the simulated radioactive substance to be measured is located. Then, according to the information of the simulated measurement object, the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance is obtained based on the generalized semi-Markov process simulation method. Then, the calibration coefficient of the measurement object is obtained 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 by using the measurement device corresponding to the measurement model. Compared with the method of relative calibration using a standard sample with a relatively low similarity to the actual object to be measured, the absolute calibration method provided by the embodiments of the present disclosure can obtain a calibration coefficient that is more matched and accurate to the object to be measured, thereby improving the accuracy of measuring the content of the radioactive substance.

[0065] Figure 3 shows Figure 2 the schematic diagram of the processing procedure of step S202 in an embodiment as shown in Figure 3 As shown, in the embodiments of the present disclosure, the above step S202 may further include the following steps.

[0066] Step S302, obtaining a cloud point map of the outer envelope of the measurement object by using laser three-dimensional scanning technology.

[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 utilized to perform laser three-dimensional scanning on a measurement object to obtain a cloud point map of the outer envelope of the measurement object. Then, based on the cloud point map, the scanned measurement object is approximated by a cube grid to establish a geometric model of the measurement object, so as to carry out neutron transport simulation calculations on the basis of cube grids (which can also be referred to as "voxel grids") with material properties set.

[0069] According to the method provided by the embodiments of the present disclosure, after obtaining the cloud point map of the outer envelope of the measurement object through laser three-dimensional scanning, a geometric model of the measurement object is established, thereby enabling direct visual modeling of samples with arbitrary shapes, and when sampling the transport mean free path (finding the intersection of the ray track and the interface) of the simulated neutron transport calculation, there is no need to solve high-order equations, effectively improving the speed of the simulation calculation.

[0070] Figure 4 Shows Figure 2 A schematic diagram of the processing process of step S208 shown in in an embodiment. As Figure 4 shown, in the embodiments of the present disclosure, the above step S208 may further include the following steps.

[0071] Step S402, 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 neutrons in the system. The state of the system is related to the events that may occur in the system. The events that may occur in the system include the event of the simulated neutron source emitting neutrons, the event of the decay of delayed neutron precursors, and the event of neutrons colliding.

[0072] In some embodiments, the state transition time information can be obtained based on the information of the events that may occur 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 according to the state transition time information. For an exemplary implementation, reference can be made to Figure 5 .

[0073] In some embodiments, the information of the neutron collision event may include the number of fissions per unit time of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, where the number of fissions per unit time can be obtained according to 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 simulated neutron source spectrum for inducing fission of the simulated radioactive material.

[0074] To be based on Figures 1A to 1C Taking the measurement model simulated by the neutron coincidence measurement device shown as an example, if the activities of two (Am-Li) neutron sources placed symmetrically up and down are Fn, the neutron flux at the voxel (i, j, k) of the measurement object by the two sources simultaneously can be calculated by the following formula (1):

[0075]

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

[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 substance to be measured) at the voxel (i, j, k) is M X , and the macroscopic cross-section of the neutron source spectrum for the induced fission of this nuclide is σ Fission , then the amount of fission occurring per second at the voxel (i, j, k) is:

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

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

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

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

[0084] In some embodiments, the information on neutron collision events further includes the leakage intensity of fission neutrons induced by neutrons emitted from a simulated neutron source in a unit volume of simulated radioactive material. The leakage intensity of 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 measurement object, fission neutrons may be self-absorbed by the measurement object and thus cannot be measured by the detector. For example, secondary neutrons generated in the region near the edge of the measurement object are more likely to be measured by the detector than neutrons generated inside the measurement object. The absorption probability P corresponding to voxels (i, j, k) at different positions can be estimated through Monte Carlo simulation of the three-dimensional voxel structure. Ab(i,j,k) , then the intensity of fission neutrons leaking from the voxel (i, j, k) within the measurement object is:

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

[0087] Step S404: Obtain the detection result of the simulated neutron detector for the neutrons generated by the simulated neutron source inducing the fission of the simulated radioactive material according to the state of the system.

[0088] In some embodiments, it is possible to simulate the use of the coincidence method by the simulated neutron detector to measure the neutrons generated by the simulated neutron source inducing the fission of the simulated radioactive material, obtain the simulated coincidence counting rate, and use the simulated coincidence counting rate and the simulated mass for fitting to obtain the calibration coefficient.

[0089] Figure 5 Shows Figure 4 The schematic diagram of the processing process of step S402 shown in Figure 5 in an embodiment. As

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

[0091] Step S504: Obtain the set of system states according to the information of the simulated neutron source, the information of the simulated measurement object, and the information of the possible events in the system. The set of system states includes the information of multiple states of the system, and the multiple states include the first state and the second state.

[0092] Step S506: Obtain state transition time information based on the information of possible events in the system and the information of multiple states of the system. The state transition time information includes the time interval for the system to transition from the first state to the second state when the first event occurs.

[0093] Step S508: Obtain the state of the system at the target time according to the state transition time information.

[0094] Taking a system with N s neutron sources (for example, the device in Figures 1A to 1C corresponds to 2 neutron sources) and N f types of fissile nuclides as an example, assuming that the delayed neutron precursors produced after the fission of each fissile nuclide can be divided into 6 groups, and denoting s as a value of the state variable, the set S of system states is:

[0095]

[0096] Among them, represents the state value of the i-th system neutron, i = 1,..., N p . and represent the position and velocity of the i-th system neutron respectively, i = 1,..., N p , N p is the total number of system neutrons. q s,i is the current state value of the i-th neutron source, i = 1,..., N s . Generally, q s,i is taken as 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 neutrons, i = 1,…, N s ; [the i-th neutron collides with the target nucleus, i = 1,…, N p ;}; Denote α as a value of an event, and the possible values of α are N s + N p in number. The possible state transition time vector C s is N s + N p -dimensional.

[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 all greater than zero, then E(s) = A.

[0099] Let P(s′; s, α) be the probability distribution of event α occurring in state s; at time t0, a state transition occurs, and the emission intensity of the i-th source neutron 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) follows the following discrete distribution:

[0100]

[0101] Where:

[0102]

[0103] Let {F α , α ∈ A} be the set of system state transition time interval distributions.

[0104] The time interval Δt for the emission of source particles from the i-th neutron source follows the distribution:

[0105]

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

[0107]

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

[0109]

[0110] The set {F α , α ∈ A} has N s +N d +N p elements.

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

[0112]

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

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

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

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

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

[0118] For s, s' ∈ S and α ∈ A, define the newly added event set N(s′; s, α) and the set O(s′; s, α) of the remaining events in the old events 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 the event α triggers the system to transfer 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 possible next events. For example, if the occurring event corresponds to a collision between a neutron and a target nuclide in the system, and this event results in the generation of n fission neutrons, then the new events refer to the events that may occur in the next state transition of the newly generated neutrons, and the old events include all source neutron emission events, various delayed neutron precursor decay events, and the events that may occur next for the neutrons that do not undergo collisions.

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

[0123]

[0124] For those with the following form

[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) represents 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 * ) and O = O(s′; s, α * ). I{·} is the indicator function. When · is satisfied, I{·} = 1; otherwise, it is 0. (Note: For O, I{c(α) - t * ≤ x(α)} is satisfied)

[0129] In this way, we can define a continuous-time GSMP as a piecewise-constant process that stays in the state Y n for a time length of t * (Y n , c n ). More precisely, let τ0 = 0, and

[0130]

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

[0132] N(t) = sup{n ≥ 0: t n ≤ t} (22)

[0133] Assume that for a finite \(t\), \(N(t)\) is almost surely finite. Then the GSMP \(Z\) associated with \(\{(Y n ,c n )\}\) is defined as: t Define as:

[0134] Z t =Y N(t) (23)

[0135] That is, \(Z\) t is the state of the GSMP at time \(t\).

[0136] The master equation of stochastic neutron dynamics can be simulated and solved using a generalized semi-Markov process. First, introduce a non-interruption condition (C1): for any \(s, s'\in S\), \(\alpha\in A\), if \(\alpha\in\varepsilon(s)\) and \(p(s; s',\alpha)>0\), then there is

[0137] For any GSMP \(\{Z t ,t\geq0\}\), record the following additional sample path characteristics:

[0138] \(\tau\) n , the update point of the \(n\)th state transition; \(\alpha\) n , the \(n\)th event; \(Y\) n , the \(n\)th state reached by the generalized semi-Markov process; \(c\) n , the state transition time interval vector after the \(n\)th state transition; \(c\) n (\(\alpha\)) is the time interval from \(\tau\) n until \(\alpha\) occurs; Given the initial state \(Y_0\) of the GSMP, let \(\tau_0 = 0\), and repeat the following recurrence formula:

[0139] \(\tau\) n+1 =\(\tau\) n +t * (Y n ,c n ) (24)

[0140] \(\alpha\) n+1 =\(\alpha\) * (Y n ,c n ) (25)

[0141] Y n+1 =\(\varphi(Y n ,\alpha n+1 ) (26)

[0142] where \(\varphi(.,.,.)\) is the mapping from state \(s\) to \(s'\) when event \(\alpha\) occurs for the \(k\)th time in state \(s\).

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

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

[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 , then

[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 by the embodiments of the present disclosure, by 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, obtaining the state transition time information according to the information of the possible events in the system and the information of multiple states of the system, and then obtaining the state of the system at the target moment according to the state transition time information, the simulation of the neutron lifetime process in the system can be realized, the accuracy of the neutron coincidence count in the system simulation measurement can be improved, and thus the accuracy of obtaining the calibration coefficient of the measurement object can be improved.

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

[0151] Reference Figure 6 , the device 60 provided by 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 can be used to establish a geometric model of the measurement object according to the appearance of the measurement object, and a predetermined area of the measurement object is attached with the radioactive substance 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 by using laser three-dimensional scanning technology, and establish a geometric model of the measurement object according to the cloud point map, or establish a geometric model of the measurement object by using CAD modeling technology.

[0154] The first acquisition module 604 can be used to acquire the relative position information between the geometric model of the measurement object and the measurement model, and 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 the material information corresponding to the measurement object and associate it with the geometric model to obtain the information of the simulated measurement object corresponding to the measurement object. The information of the simulated measurement object includes the attributes of the basic constituent substances, the attributes and simulated mass of the simulated radioactive substance, and the simulated position of the simulated radioactive substance to be measured corresponding to the predetermined area in the simulated measurement object.

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

[0157] The simulation measurement module 608 can also be used to simulate the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time based on the simulation method of the generalized semi-Markov process. 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. The events that may occur in the system include the event of the simulated neutron source emitting neutrons, the event of the decay of the delayed neutron precursor nucleus, and the event of the neutrons colliding; obtain the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance induced by the simulated neutron source according to the state of the system.

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

[0159] The information of the neutron collision event can include the unit time fission amount of the simulated radioactive material induced by the neutrons emitted by the simulated neutron source per unit volume, where: the unit time fission amount is obtained according to 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 simulated neutron source spectrum for the induced fission of the simulated radioactive material.

[0160] The information of the neutron collision event can also include the fission neutron intensity generated by the neutrons emitted by the simulated neutron source inducing the fission of the simulated radioactive material per unit volume, where: the fission neutron intensity is obtained according to the unit time fission amount and the number of neutrons generated per fission, and the number of neutrons generated per fission follows the Terrel distribution.

[0161] The information of the neutron collision event can also include the leakage intensity of the fission neutrons generated by the neutrons emitted by the simulated neutron source inducing the fission of the simulated radioactive material per unit volume, where: the leakage intensity of the fission neutrons is obtained according to 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 generated by the simulated neutron source inducing the fission of the simulated radioactive material by the coincidence method, and obtain the simulated coincidence counting rate.

[0163] The obtaining 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 by using the measuring device corresponding to the measurement model according to the calibration coefficient.

[0164] The obtaining module 610 can also be used to fit the target linear function by using the simulated mass of the simulated radioactive material and the simulated coincidence counting rate, and obtain the parameters of the target linear function as the calibration coefficient. The variables of the target linear function include the mass of the radioactive material and the coincidence counting rate of the neutron detector.

[0165] The specific implementation of each module in the device provided by the embodiments of the present disclosure may refer to the content in the above method, and will not be elaborated here.

[0166] Figure 7 The structural schematic diagram of an electronic device in the embodiments of the present disclosure is shown. It should be noted that Figure 7 The shown device takes a computer system as an example only, and should not bring any limitation to the functions and usage scope of the embodiments of the present disclosure.

[0167] As Figure 7 shown, the device 700 includes a central processing unit (CPU) 701, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 702 or the program loaded from the storage section 708 into the 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. The 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 required. 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 required, so that the computer program read from it can be installed into the storage section 708 as required.

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

[0170] It should be noted that the computer-readable medium shown in this disclosure can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of a computer-readable storage medium can 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 this disclosure, a computer-readable storage medium can be any tangible medium that contains or stores a program, which can be used by or in conjunction with an instruction execution system, apparatus, or device. And in this disclosure, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can 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 a computer-readable medium can 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 flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram can represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in a block can occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and the combination of blocks in a block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0172] The modules involved in the embodiments of the present disclosure can be implemented in software or in hardware. The described modules can also be provided in a processor. For example, it can 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. Among them, the names of these modules do not constitute a limitation to the module itself in some cases. For example, the data acquisition module can also be described as "a module for acquiring initial data from the connected server side".

[0173] As another aspect, the present disclosure also provides a computer-readable medium, which can be included in the device described in the above embodiments; or can exist alone without being assembled into the device. The above computer-readable medium carries one or more programs. When the above one or more programs are executed by the device, the device is configured to implement:

[0174] Establish a geometric model of the measurement object according to the appearance of the measurement object, and a predetermined area of the measurement object is attached with the radioactive substance to be measured; obtain the relative position information between the geometric model of the measurement object and the measurement model, and the measurement model includes a simulated neutron detector; obtain the material information corresponding to the measurement object and associate it with the geometric model to obtain the information of the simulated measurement object corresponding to the measurement object, and the information of the simulated measurement object includes the attributes of the basic constituent substances, the attributes and simulated mass of the simulated radioactive substance, and the simulated position of the simulated radioactive substance to be measured corresponding to the predetermined area in the simulated measurement object; obtain the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance based on the generalized semi-Markov process simulation method according to the information of the simulated measurement object; obtain the calibration coefficient of the measurement 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 by using the measurement device corresponding to the measurement model according to the calibration coefficient.

[0175] The embodiments of the present disclosure provide a computer program product or a computer program, which includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the 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 various alternative implementation manners.

[0176] The above specifically shows and describes the exemplary embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the detailed structures, setting manners, or implementation methods described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent settings included within the spirit and scope of the appended claims.

Claims

1. A method for measuring the content of radioactive substances, characterized in that, Including: Establish a geometric model of the measurement object according to the appearance of the measurement object, with a radioactive substance to be measured attached to a predetermined area of the measurement object; Obtain the relative position information between the geometric model of the measurement object and the measurement model, where the measurement model includes a simulated neutron detector and a simulated neutron source; Obtain the material information corresponding to the measurement object and associate it with the geometric model to obtain the information of the simulated measurement object corresponding to the measurement object, where the information of the simulated measurement object includes the attributes of the basic constituent substances, the attributes and simulated mass of the simulated radioactive substance, and the simulated position of the simulated radioactive substance to be measured corresponding to the predetermined area in the simulated measurement object; Based on the generalized semi-Markov process simulation method, simulate the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time. The information of the state of the system includes the position and velocity of neutrons in the system. The state of the system is related to the events that may occur in the system. The events that may occur in the system include the event of the simulated neutron source emitting neutrons, the event of the decay of delayed neutron precursors, and the event of neutrons colliding. The information of the neutron collision event includes the leakage intensity of fission neutrons induced by the neutrons emitted by the simulated neutron source in the unit volume of the simulated radioactive substance. Among them, the leakage intensity of the fission neutrons is obtained according to the fission neutron intensity and the absorption probability of the simulated measurement object; Obtain the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive substance induced by the simulated neutron source according to the state of the system; Obtain the calibration coefficient of the measurement 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 by using the measurement device corresponding to the measurement model according to the calibration coefficient.

2. The method according to claim 1, wherein Based on the generalized semi-Markov process simulation method, simulating the change of the state of the system composed of the simulated neutron source and the simulated measurement object over time includes: Obtain the 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. The set of events that may occur in the system includes the information of the events that may occur in the system, and the events that may occur in the system include the first event; Obtain the set of states of the system according to the information of the simulated neutron source, the information of the simulated measurement object, and the information of the events that may occur in the system. The set of states of the system includes the information of multiple states of the system, and the multiple states include the first state and the second state; Obtain the state transition time information according to the information of the events that may occur in the system and the information of the multiple states of the system. The state transition time information includes the time interval for the system to transfer from the first state to the second state when the first event occurs; Obtain the state of the system at the target time according to the state transition time information.

3. The method according to claim 2, wherein The information on the neutron collision events includes the number of fissions per unit time of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, where: The number of fissions 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 simulated radioactive material for induced fission with respect to the energy spectrum of the simulated neutron source.

4. The method according to claim 3, wherein The information on the neutron collision events also includes the intensity of the fission neutrons generated by the fission of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source, where: The intensity of the fission neutrons is obtained based on the number of fissions per unit time and the number of neutrons generated per fission, and the number of neutrons generated per fission follows the Terrel distribution.

5. The method according to any one of claims 1 to 4, characterized in that, Based on the state of the system, the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source is obtained, including: Simulating that the simulated neutron detector measures the neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source using the coincidence method to obtain the simulated coincidence counting rate.

6. The method according to claim 5, characterized in that Based on the simulated mass of the simulated radioactive material and the detection result of the simulated neutron detector, the calibration coefficient of the measurement object is obtained, including: Fitting the target linear function using the simulated mass of the simulated radioactive material and the simulated coincidence counting rate, and the parameters of the target linear function obtained are the calibration coefficients. The variables of the target linear function include the mass of the radioactive material and the coincidence counting rate of the neutron detector.

7. The method according to any one of claims 1 to 4, characterized in that Based on the appearance of the measurement object, a geometric model of the measurement object is established, including: Using laser three-dimensional scanning technology to obtain the cloud point map of the envelope of the measurement object, and establishing the geometric model of the measurement object based on the cloud point map, or, Using CAD modeling technology to establish the geometric model of the measurement object.

8. A radioactive substance content measuring device, characterized in that, Including: A geometric modeling module for establishing a geometric model of the measurement object based on the appearance of the measurement object, with a predetermined area of the measurement object attached with the radioactive material to be measured; A first acquisition module for acquiring the relative position information between the geometric model of the measurement object and the measurement model, where the measurement model includes a simulated neutron detector and a simulated neutron source; A second acquisition module for acquiring the material information corresponding to the measurement object and associating it with the geometric model to obtain the information of the simulated measurement object corresponding to the measurement object. The information of the simulated measurement object includes the attributes of the basic constituent materials, the attributes and simulated mass of the simulated radioactive material, and the simulated position of the simulated radioactive material to be measured corresponding to the predetermined area in the simulated measurement object; A simulation measurement module, which is used to simulate 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 neutrons in the system. The state of the system is related to the events that may occur in the system. The events that may occur in the system include the event of the simulated neutron source emitting neutrons, the event of the decay of delayed neutron precursors, and the event of neutrons colliding. The information of the event of neutrons colliding includes the leakage intensity of fission neutrons generated by the fission of the simulated radioactive material per unit volume induced by the neutrons emitted by the simulated neutron source. Among them, the leakage intensity of the fission neutrons is obtained according to the fission neutron intensity and the absorption probability of the simulated measurement object; obtaining the detection result of the simulated neutron detector for the neutrons generated by the fission of the simulated radioactive material induced by the simulated neutron source according to the state of the system; An acquisition module, which is 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 by using the measuring device corresponding to the measurement model according to the calibration coefficient.

9. A neutron coincidence measurement device, characterized in that, Comprising: A detector main body, the detector main body includes a sample cavity and a neutron detector. The sample cavity is used to place the measurement object including the radioactive material to be measured, and the neutron detector is used to detect the neutrons generated by the fission of the radioactive material to be measured; An electronic circuit connected to the neutron detector, which is used to receive the detection count of the neutron detector and process it, and output a corresponding signal; Calibration coefficient acquisition software, which is used to implement the method according to any one of claims 1-7 to obtain the calibration coefficient of the measurement object; Measurement software, which is used to obtain the content of the radioactive material to be measured according to the output signal of the electronic circuit and the calibration coefficient of the measurement object.

10. An electronic device, comprising: A memory, a processor, and executable instructions stored in the memory and executable in the processor, characterized in that when the processor executes the executable instructions, the method according to any one of claims 1-7 is implemented.

11. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that, When the executable instructions are executed by the processor, the method according to any one of claims 1-7 is implemented.

12. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, the method according to any one of claims 1-7 is implemented.

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