Method for detecting radioactive contamination of irregular material

Abstract

The application discloses a method for detecting radioactive contamination of irregular materials, which comprises the following steps: randomly extracting a point in the point cloud data of the irregular materials as a radiation point according to the contamination type of the irregular materials; randomly extracting a point in the detector end face of the detector as a detection point; taking the intersection point of the line connecting the radiation point and the detection point and the surface of the irregular materials as a penetration point; repeating the extraction of the radiation point and the detection point for a preset number of times; and calculating the radioactive contamination of the irregular materials according to the distance between the radiation point and the penetration point and the distance between the detection point and the penetration point extracted for the preset number of times. The application solves the problem that the radioactive contamination of large-volume irregular materials cannot be calculated, and solves the problems that the current method needs to develop a calibration source according to the material medium, has high technical requirements for the implementers, has a long simulation calculation time, and is not easy to transplant.

Description

Technical Field

[0001] This invention relates to the field of radioactive detection technology, and in particular to a method for detecting radioactive contamination in irregular materials. Background Technology

[0002] In nuclear power plants, nuclear reprocessing plants, and fields involving radioactivity such as radiopharmaceutical production and accelerator therapy, a certain amount of solid radioactive waste is typically generated. Solid radioactive waste is usually stored in radioactive waste containers ranging from 50L to 400L. According to relevant national requirements, before solid radioactive waste is transported out of the country, it must be measured to obtain characteristics such as the type of radionuclide, activity concentration, and surface radiation dose rate level.

[0003] Currently, radioactive solid waste with specific geometric shapes is mainly measured using technologies such as SGS and TGS. SGS is a non-destructive testing technique used to detect the types and activities of radionuclides in radioactive solid waste. TGS is also a non-destructive testing technique, primarily used to characterize low- and intermediate-level radioactive waste generated during the operation of nuclear power plants and other nuclear facilities. However, there is no feasible method for measuring irregularly shaped materials. They typically need to be prepared, sorted, and stored in specific containers or cabinets before measurement. A major problem in radioactive waste measurement is the large volume of the materials (50L–400L). Large-volume materials are difficult to measure using radioactive calibration sources of the same size and medium, and the calibration source method cannot calculate the surface contamination detection efficiency for objects of thickness.

[0004] Currently, there are two main methods: Monte Carlo simulation calibration and simulating a uniform volume source by distributing line sources (or point sources) within a matrix according to a certain pattern. Monte Carlo simulation calibration has drawbacks, including high technical requirements for personnel, long simulation calculation times, and difficulty in porting the method. Simulating a uniform volume source by distributing line sources (or point sources) within a matrix according to a certain pattern has significant errors, and the number and distribution of line sources vary considerably for different matrices. Furthermore, to calibrate materials in different media, a large number of calibration sources need to be prepared. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address at least one defect of the related technologies mentioned in the background: the inability to calculate radioactive contamination of large-volume irregular materials, and the current methods have problems such as the need to formulate a calibration source according to the material medium, or high technical requirements for implementers, long simulation calculation time, and difficulty in method portability. The present invention provides a method for detecting radioactive contamination of irregular materials.

[0006] The technical solution adopted by this invention to solve its technical problem is: to construct a method for detecting radioactive contamination in irregular materials, the method comprising the following steps:

[0007] Based on the contamination type of the irregular material, a point is randomly selected from the point cloud data of the irregular material as the emission point of the ray.

[0008] A point is randomly selected within the detector end face of the detector as the detection point;

[0009] The point where the line connecting the launch point and the probe point intersects the irregular material surface is taken as the penetration point;

[0010] Repeat the sampling of launch and probe points a preset number of times;

[0011] Radioactive contamination of irregular materials is calculated based on the distances between the emission point and the penetration point extracted a preset number of times, as well as the distances between the detection point and the penetration point extracted a preset number of times.

[0012] In some embodiments, a point is randomly selected from the point cloud data of the irregular material based on the type of contamination of the irregular material, and used as the emission point of the ray. This is further supported by:

[0013] Determine the type of contamination in irregular materials.

[0014] In some embodiments, determining the type of contamination of irregular materials includes:

[0015] The type of irregular material contamination is determined based on the source of the irregular material contamination and the material composition of the irregular material.

[0016] In some embodiments, after determining the type of contamination by irregular materials, the method further includes:

[0017] The point cloud data of the irregular material is obtained by 3D scanning of the irregular material.

[0018] In some embodiments, irregular material contamination types include: volume contamination and surface contamination;

[0019] The point cloud data of irregular materials includes: voxel point cloud data of irregular materials and point cloud data of the surface of irregular materials.

[0020] In some embodiments, a point is randomly selected from the point cloud data of the irregular material according to the contamination type of the irregular material as the emission point of the ray, including:

[0021] If the irregular material contamination type is volume contamination, then a point is randomly selected from the irregular material voxel point cloud data as the voxel emission point of the ray, denoted as s1(x,y,z).

[0022] If the irregular material contamination type is surface contamination, then a point is randomly selected from the point cloud data of the irregular material surface as the surface emission point of the ray, denoted as s(x,y,z);

[0023] Furthermore, the detection point is denoted as d(x,y,z).

[0024] In some embodiments, the point where the line connecting the emission point and the detection point intersects the irregular material surface is taken as the penetration point, including:

[0025] If the irregular material contamination type is volume contamination, then the point where the line connecting the voxel emission point s1(x,y,z) and the detection point d(x,y,z) intersects the surface of the irregular material is taken as the voxel penetration point t1(x,y,z).

[0026] If the irregular material contamination type is surface contamination, then the point where the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the surface of the irregular material is taken as the surface penetration point t(x,y,z).

[0027] In some embodiments, if the irregular material contamination type is surface contamination, then the point where the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t(x,y,z), including:

[0028] If the irregular material contamination type is surface contamination, then determine whether the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects with the surface of the irregular material.

[0029] If so, the surface emission point s(x,y,z) is a surface emission point outside the detection range of the detector, denoted as s2(x,y,z), and the point where the line connecting the surface emission point s2(x,y,z) outside the detection range of the detector and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t2(x,y,z).

[0030] If not, the surface emission point s(x,y,z) is the surface emission point within the detector's detection range, denoted as s3(x,y,z), and there is no surface penetration point.

[0031] In some embodiments, the emission point and the detection point are repeatedly extracted a preset number of times, including: if the irregular material contamination type is volume contamination, the voxel emission point s1(x,y,z) and the detection point d(x,y,z) are repeatedly extracted p times.

[0032] Based on the distances between the emission point and the penetration point extracted a preset number of times, and the distances between the detection point and the penetration point extracted a preset number of times, the radioactive contamination of irregular materials is calculated, including: if the contamination type of irregular materials is volume contamination, the distance l1 between the voxel emission point s1(x,y,z) and the detection point d(x,y,z) extracted p times, and the distance l1 between the voxel emission point s1(x,y,z) and the voxel penetration point t1(x,y,z) extracted p times are calculated. ' Calculate the radioactive contamination of irregular material bodies ;

[0033] Radioactive contamination of irregular material bodies The calculation formula is: ;

[0034] Where μ is the linear attenuation coefficient of the material, l1 is the distance from the voxel emission point s1(x,y,z) of the k-th sampling to the detection point d(x,y,z), and l1 ' The distance from the voxel emission point s1(x,y,z) of the kth sampling to the voxel penetration point t1(x,y,z).

[0035] In some embodiments, repeatedly sampling the emission point and the detection point a preset number of times includes: if the surface is contaminated with irregular material contamination, determining whether the surface emission point is within the detection range of the detector;

[0036] If the surface emission point is a surface emission point s2(x,y,z) that is not within the detection range of the detector, then the surface emission point s2(x,y,z) and the detection point d(x,y,z) that are not within the detection range of the detector are sampled repeatedly n times.

[0037] If the surface emission point is the surface emission point s3(x,y,z) within the detector's detection range, then the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range are sampled repeatedly m times.

[0038] The radioactive contamination of irregular materials is calculated based on the distance between the emission point and the penetration point sampled a preset number of times and the distance between the detection point and the penetration point sampled a preset number of times. This includes: if the contamination type of irregular materials is surface contamination, then determining whether the surface emission point is within the detection range of the detector.

[0039] If the surface emission point is a surface emission point s2(x,y,z) that is outside the detector's detection range, then based on the distance l2 between the n sampled surface emission points s2(x,y,z) that are outside the detector's detection range and the detection point d(x,y,z), and the distance l2 between the n sampled surface emission points s2(x,y,z) and the surface penetration point t2(x,y,z),... ' ;as well as,

[0040] If the surface emission point is a surface emission point s3(x,y,z) within the detector's detection range, then the distance l3 between the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range, obtained from m samplings, can be used to calculate the radioactive contamination on the surface of the irregular material. ;

[0041] Radioactive contamination on irregular material surfaces The calculation formula is: ;

[0042] Where μ is the linear attenuation coefficient of the material, l2 is the distance from the surface emission point s2(x,y,z) outside the detector's detection range in the i-th sampling to the detector point d(x,y,z), and l2 ' Let t2 be the distance from the surface emission point s2(x,y,z) that is outside the detector's detection range during the i-th sampling to the surface penetration point t2(x,y,z).

[0043] l3 is the distance from the surface emission point s3(x,y,z) to the detection point d(x,y,z) within the detector's detection range during the j-th sampling.

[0044] By implementing this invention, the following beneficial effects are achieved:

[0045] This invention calculates radioactive contamination of irregular materials by randomly selecting a point from the point cloud data of the irregular material based on the type of contamination, using it as the emission point; randomly selecting a point within the detector end face of the detector, using it as the detection point; and selecting the point where the line connecting the emission point and the detection point intersects the surface of the irregular material, using it as the penetration point. The emission point and detection point are repeatedly selected a preset number of times. Based on the distances between the emission point and the penetration point selected a preset number of times, and the distances between the detection point and the penetration point selected a preset number of times, the radioactive contamination of the irregular material is calculated. This achieves the calculation of radioactive contamination of large-volume irregular materials and overcomes the problems of current methods, such as the need to specify a calibration source based on the material medium, high technical requirements for implementers, long simulation calculation time, and difficulty in method portability. Attached Figure Description

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0047] Figure 1 A flowchart of one embodiment of the method for detecting radioactive contamination in irregular materials according to the present invention is shown;

[0048] Figure 2 The diagram illustrates a 3D scanning of irregular materials in one embodiment of the method for detecting radioactive contamination in irregular materials according to the present invention.

[0049] Figure 3This diagram illustrates a method for detecting radioactive contamination in irregular materials according to the present invention, showing voxel point cloud data and surface point cloud data of the irregular material.

[0050] Figure 4 This diagram illustrates a surface point cloud data of an embodiment of the method for detecting radioactive contamination in irregular materials according to the present invention, showing the acquisition of point cloud data of irregular materials.

[0051] Figure 5 The diagram illustrates a sampling process for calculating radioactive contamination of an irregular material volume, as per an embodiment of the method for detecting radioactive contamination in irregular materials according to the present invention.

[0052] Figure 6 The diagram illustrates a sampling process for calculating radioactive contamination on the surface of an irregular material, as part of an embodiment of the method for detecting radioactive contamination in irregular materials according to the present invention. Detailed Implementation

[0053] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0054] It should be noted that the flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily need to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0055] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0056] like Figure 1 As shown, some embodiments of the present invention disclose a method for detecting radioactive contamination in irregular materials, the method comprising the following steps:

[0057] Based on the contamination type of the irregular material, a point is randomly selected from the point cloud data of the irregular material as the emission point of the ray.

[0058] A point is randomly selected within the detector end face of the detector as the detection point; the point where the line connecting the emission point and the detection point intersects the surface of the irregular material is taken as the penetration point.

[0059] Repeat the sampling of launch and probe points a preset number of times;

[0060] Radioactive contamination of irregular materials is calculated based on the distances between the emission point and the penetration point extracted a preset number of times, as well as the distances between the detection point and the penetration point extracted a preset number of times.

[0061] The detector end face refers to the surface of the detector crystal facing the irregular material. Only this surface can receive the rays emitted by the irregular material. The detector end face is usually circular (high-purity germanium detector, sodium iodide detector) or square (zinc cadmium telluride detector, plastic scintillator detector). A point is randomly selected within the detector end face as the ray detection point. That is, the line connecting the ray emitted from the randomly selected emission point to the randomly selected detection point on the detector end face.

[0062] In some embodiments, a point is randomly selected from the point cloud data of the irregular material according to the contamination type of the irregular material as the emission point of the ray. The method further includes determining the contamination type of the irregular material.

[0063] In some embodiments, determining the contamination type of irregular materials includes: determining the contamination type of irregular materials based on the contamination source term and the material of the irregular materials.

[0064] like Figure 2 As shown, in some embodiments, after determining the type of contamination of the irregular material, the method further includes: obtaining point cloud data of the irregular material by performing a 3D scan on the irregular material.

[0065] Irregular materials are scanned 360° using a 3D laser scanning device. A rotating table rotates the irregular material to ensure it is within the scanning field of view of the 3D laser scanner, allowing for a 3D model to be acquired. This 3D model can then be converted into point cloud data of the irregular material. Figure 3 As shown, point cloud data of irregular materials refers to a point dataset composed of three-dimensional spatial point coordinates.

[0066] In some embodiments, irregular material contamination types include: volume contamination and surface contamination.

[0067] The point cloud data for irregular materials includes: voxel point cloud data of irregular materials and surface point cloud data of irregular materials. Specifically, the surface point cloud data of irregular materials includes... Figure 4 As shown.

[0068] The type of contamination in materials is mainly related to the source of contamination and the material itself. Contamination can be categorized into two types: bulk contamination and surface contamination. Bulk contamination occurs when radioactive nuclides are uniformly distributed throughout the material, while surface contamination occurs when radioactive nuclides are uniformly distributed on the surface of the material. Examples of bulk contamination sources include resins and filter cartridges, while examples of surface contamination sources include metals and glass. These examples are merely illustrative and not intended to limit the scope of this application; other materials may also be included.

[0069] In some embodiments, a point is randomly selected from the point cloud data of the irregular material according to the contamination type of the irregular material as the emission point of the ray, including:

[0070] If the irregular material contamination type is volume contamination, then a point is randomly selected from the voxel point cloud data of the irregular material as the voxel emission point of the ray, denoted as s1(x,y,z). Specifically: if the irregular material contamination is volume contamination, voxel points are randomly selected from the voxel point cloud data of the irregular material as voxel emission points of the ray, and each voxel emission point is represented by a three-dimensional Cartesian coordinate system, denoted as s1(x,y,z);

[0071] If the irregular material contamination type is surface contamination, then a point is randomly selected from the point cloud data of the irregular material surface as the surface emission point of the ray, denoted as s(x,y,z).

[0072] In addition, a point is randomly selected within the detector end face of the detector as the detection point, denoted as d(x,y,z).

[0073] In some embodiments, the point where the line connecting the emission point and the detection point intersects the irregular material surface is taken as the penetration point, including:

[0074] If the irregular material contamination type is volume contamination, then the point where the line connecting the voxel emission point s1(x,y,z) and the detection point d(x,y,z) intersects the surface of the irregular material is taken as the voxel penetration point t1(x,y,z).

[0075] In some embodiments, the voxel penetration point t1(x,y,z) is the intersection of the path from the voxel emission point s1(x,y,z) to the detection point d(x,y,z) and the irregular material surface;

[0076] In other embodiments, the point in the point cloud data of the irregular material surface that is closest to the line connecting the voxel emission point s1(x,y,z) to the detection point d(x,y,z) is selected as the voxel penetration point t1(x,y,z).

[0077] If the irregular material contamination type is surface contamination, then the point where the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the surface of the irregular material is taken as the surface penetration point t(x,y,z).

[0078] In some embodiments, if the irregular material contamination type is surface contamination, then the point where the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t(x,y,z), including:

[0079] If the irregular material contamination type is surface contamination, then determine whether the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects with the surface of the irregular material.

[0080] If so, the surface emission point s(x,y,z) is a surface emission point outside the detection range of the detector, denoted as s2(x,y,z), and the point where the line connecting the surface emission point s2(x,y,z) outside the detection range of the detector and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t2(x,y,z).

[0081] If not, the surface emission point s(x,y,z) is the surface emission point within the detector's detection range, denoted as s3(x,y,z), and there is no surface penetration point.

[0082] For surface contamination sources of irregular materials, there are two scenarios regarding the distance from the surface emission point s(x,y,z) to the detection point d(x,y,z). One scenario is that the surface emission point is outside the detector's detection range, requiring the path to pass through the irregular material, resulting in a penetration point. The other scenario is that the surface emission point is located to one side of the detector, within its detection range, allowing the path to the detection point to pass through the irregular material without a penetration point. To identify the presence of penetration points, the point cloud data of the irregular material surface is sampled, and the point with the shortest distance to the ray path (i.e., the path from the surface emission point to the detection point) is selected. If the sampled point with the shortest distance is within a preset range from the surface emission point, there is no penetration point; otherwise, a surface penetration point exists, and the sampled point is the surface penetration point.

[0083] like Figure 5 As shown, in some embodiments, the emission point and the detection point are repeatedly extracted a preset number of times, including: if the irregular material contamination type is volume contamination, then the voxel emission point s1(x,y,z) and the detection point d(x,y,z) are repeatedly extracted p times.

[0084] Radioactive contamination of irregular materials is calculated based on the distances between the emission point and penetration point extracted a preset number of times, and the distances between the detection point and penetration point extracted a preset number of times. This includes: if the contamination type of the irregular material is volume contamination, the distance l1 between the voxel emission point s1(x,y,z) and the detection point d(x,y,z) extracted p times, and the distance t1(x,y,z) between the voxel emission point s1(x,y,z) and the voxel penetration point t1(x,y,z) extracted p times. Calculate the radioactive contamination of irregular material bodies ;

[0085] Wherein, the distance between the voxel emission point s1(x,y,z) and the voxel penetration point t1(x,y,z) is... The attenuation path of the voxel emission point ray is defined as d(x,y,z). Within this attenuation path, the voxel emission point ray is attenuated by the self-absorption of irregular materials. The distance between the detection point d(x,y,z) and the voxel penetration point t1(x,y,z) is defined as the propagation path of the voxel emission point ray. Within this propagation path, the absorption attenuation of the voxel emission point ray is negligible. The attenuation path and the propagation path of the voxel emission point ray together constitute the voxel emission point ray path l1.

[0086] Radioactive contamination of irregular material bodies The calculation formula is: ;

[0087] Where μ is the linear attenuation coefficient of the material, and l1 is the distance from the voxel emission point s1(x,y,z) of the k-th sampling to the detection point d(x,y,z). Let be the distance from the voxel emission point s1(x,y,z) of the k-th sampling to the voxel penetration point t1(x,y,z), and e be the natural constant.

[0088] like Figure 6 As shown, in some embodiments, the emission point and the detection point are repeatedly sampled a preset number of times, including: if the surface is contaminated with irregular material contamination, it is determined whether the surface emission point is within the detection range of the detector;

[0089] If the surface emission point is a surface emission point s2(x,y,z) that is not within the detection range of the detector, then the surface emission point s2(x,y,z) and the detection point d(x,y,z) that are not within the detection range of the detector are sampled repeatedly n times.

[0090] If the surface emission point is the surface emission point s3(x,y,z) within the detector's detection range, then the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range are sampled repeatedly m times.

[0091] The radioactive contamination of irregular materials is calculated based on the distance between the emission point and the penetration point sampled a preset number of times and the distance between the detection point and the penetration point sampled a preset number of times. This includes: if the contamination type of irregular materials is surface contamination, then determining whether the surface emission point is within the detection range of the detector.

[0092] If the surface emission point is a surface emission point s2(x,y,z) that is outside the detector's detection range, then based on the distance l2 between the n sampled surface emission points s2(x,y,z) that are outside the detector's detection range and the detection point d(x,y,z), and the distance l2 between the n sampled surface emission points s2(x,y,z) and the surface penetration point t2(x,y,z),... ' ;as well as,

[0093] If the surface emission point is a surface emission point s3(x,y,z) within the detector's detection range, then the distance l3 between the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range, obtained from m samplings, can be used to calculate the radioactive contamination on the surface of the irregular material. .

[0094] Among them, the distance l2 between the surface emission point s2(x,y,z) outside the detector's detection range and the surface penetration point t2(x,y,z) is... ' The attenuation path of surface-emitted rays outside the detector's detection range is defined as l2. Within this attenuation path, the rays are attenuated by the self-absorption of irregular materials. The distance between the detection point d(x,y,z) and the surface penetration point t2(x,y,z) represents the propagation path of these rays. Within this propagation path, the absorption attenuation of these rays is negligible. The attenuation path and propagation path of these rays together constitute the path l2 of the surface-emitted rays outside the detector's detection range.

[0095] The distance l3 between the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range is the propagation path of the surface emission point ray within the detector's detection range. Within the propagation path of the surface emission point ray within the detector's detection range, the absorption attenuation of the surface emission point ray can be ignored. The propagation path of the surface emission point ray within the detector's detection range constitutes the surface emission point ray path within the detector's detection range.

[0096] Radioactive contamination on irregular material surfaces The calculation formula is: ;

[0097] Where μ is the linear attenuation coefficient of the material, l2 is the distance from the surface emission point s2(x,y,z) outside the detector's detection range in the i-th sampling to the detector point d(x,y,z), and l2 ' Let be the distance from the surface emission point s2(x,y,z) outside the detector's detection range in the i-th sample to the surface penetration point t2(x,y,z), where e is the natural constant. Let l3 be the distance from the surface emission point s3(x,y,z) within the detector's detection range in the j-th sample to the detection point d(x,y,z).

[0098] By implementing this invention, the following beneficial effects are achieved:

[0099] This invention calculates radioactive contamination of irregular materials by randomly selecting a point from the point cloud data of the irregular material based on the type of contamination, using it as the emission point; randomly selecting a point within the detector end face of the detector, using it as the detection point; and selecting the point where the line connecting the emission point and the detection point intersects the surface of the irregular material, using it as the penetration point. The emission point and detection point are repeatedly selected a preset number of times. Based on the distances between the emission point and the penetration point selected a preset number of times, and the distances between the detection point and the penetration point selected a preset number of times, the radioactive contamination of the irregular material is calculated. This achieves the calculation of radioactive contamination of large-volume irregular materials and overcomes the problems of current methods, such as the need to specify a calibration source based on the material medium, high technical requirements for implementers, long simulation calculation time, and difficulty in method portability.

[0100] It is understood that the above embodiments only illustrate some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above embodiments or technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the preceding and following embodiments. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A method for detecting radioactive contamination in irregular materials, characterized in that, The method includes the following steps: Based on the type of contamination (volume or surface) of the irregular material, a point is randomly selected from the point cloud data of the irregular material as the emission point of the ray. Specifically: if the contamination type of the irregular material is volume contamination, a point is randomly selected from the voxel point cloud data of the irregular material as the voxel emission point of the ray, denoted as s1(x,y,z); if the contamination type of the irregular material is surface contamination, a point is randomly selected from the surface point cloud data of the irregular material as the surface emission point of the ray, denoted as s(x,y,z). A point is randomly selected within the detector end face of the detector and designated as the detection point d(x,y,z); The point where the line connecting the emission point and the detection point intersects the surface of the irregular material is taken as the penetration point, including: if the irregular material contamination type is volume contamination, then the point where the line connecting the voxel emission point s1(x,y,z) and the detection point d(x,y,z) intersects the surface of the irregular material is taken as the voxel penetration point t1(x,y,z). Alternatively, if the irregular material contamination type is surface contamination, then the point where the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t(x,y,z). This includes: determining whether the line connecting the surface emission point s(x,y,z) and the detection point d(x,y,z) intersects the irregular material surface; if so, then the surface emission point s(x,y,z) is a surface emission point outside the detector's detection range, denoted as s2(x,y,z), and the point where the line connecting the surface emission point s2(x,y,z) outside the detector's detection range and the detection point d(x,y,z) intersects the irregular material surface is taken as the surface penetration point t2(x,y,z); if not, then the surface emission point s(x,y,z) is a surface emission point within the detector's detection range, denoted as s3(x,y,z), and there is no surface penetration point. The emission point and detection point are sampled repeatedly a preset number of times, including: if the irregular material contamination type is volume contamination, the voxel emission point s1(x,y,z) and detection point d(x,y,z) are sampled repeatedly p times; or, if the irregular material contamination type is surface contamination, it is determined whether the surface emission point is within the detector's detection range. If the surface emission point is a surface emission point s2(x,y,z) outside the detector's detection range, the surface emission point s2(x,y,z) and detection point d(x,y,z) outside the detector's detection range are sampled repeatedly n times; if the surface emission point is a surface emission point s3(x,y,z) within the detector's detection range, the surface emission point s3(x,y,z) and detection point d(x,y,z) within the detector's detection range are sampled repeatedly m times. Based on the distances between the emission point and the penetration point extracted a preset number of times, and the distances between the detection point and the penetration point extracted a preset number of times, the radioactive contamination of irregular materials is calculated, including: if the contamination type of irregular materials is volume contamination, the distance l1 between the voxel emission point s1(x,y,z) and the detection point d(x,y,z) extracted p times, and the distance l1 between the voxel emission point s1(x,y,z) and the voxel penetration point t1(x,y,z) extracted p times are calculated. ' Radioactive contamination of irregular material volumes was calculated. Radioactive contamination from irregularly shaped materials The calculation formula is: Where μ is the linear attenuation coefficient of the material, l1 is the distance from the voxel emission point s1(x,y,z) of the k-th sampling to the detection point d(x,y,z), and l1 ' The distance from the voxel emission point s1(x,y,z) of the kth sampling to the voxel penetration point t1(x,y,z); Alternatively, if the irregular material contamination type is surface contamination, then determine whether the surface emission point is within the detector's detection range; if the surface emission point is a surface emission point s2(x,y,z) outside the detector's detection range, then based on the distance l2 between the n sampled surface emission points s2(x,y,z) outside the detector's detection range and the detection point d(x,y,z), and the distance l2 between the n sampled surface emission points s2(x,y,z) and the surface penetration point t2(x,y,z),... ' Furthermore, if the surface emission point is a surface emission point s3(x,y,z) within the detector's detection range, then the distance l3 between the surface emission point s3(x,y,z) and the detection point d(x,y,z) within the detector's detection range, obtained from m samplings, is used to calculate the radioactive contamination on the surface of the irregular material. Radioactive contamination on irregular material surfaces The calculation formula is: Where μ is the linear attenuation coefficient of the material, l2 is the distance from the surface emission point s2(x,y,z) outside the detector's detection range in the i-th sampling to the detection point d(x,y,z), and l2 ' l1 is the distance from the surface emission point s2(x,y,z) outside the detector's detection range in the i-th sampling to the surface penetration point t2(x,y,z), and l2 is the distance from the surface emission point s3(x,y,z) within the detector's detection range in the j-th sampling to the detection point d(x,y,z).

2. The method for detecting radioactive contamination in irregular materials according to claim 1, characterized in that, Based on the contamination type of the irregular material, a point is randomly selected from the point cloud data of the irregular material as the emission point of the ray. This also includes: Determine the type of contamination in irregular materials.

3. The method for detecting radioactive contamination in irregular materials according to claim 2, characterized in that, Determining the type of contamination in irregularly shaped materials includes: The type of irregular material contamination is determined based on the source of the irregular material contamination and the material composition of the irregular material.

4. The method for detecting radioactive contamination in irregular materials according to claim 2, characterized in that, Determining the type of contamination in irregularly shaped materials also includes: The point cloud data of the irregular material is obtained by 3D scanning of the irregular material.

5. The method for detecting radioactive contamination in irregular materials according to claim 3 or 4, characterized in that, The point cloud data of irregular materials includes: voxel point cloud data of irregular materials and point cloud data of the surface of irregular materials.

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