A radiation detector data fusion method and apparatus

Abstract

The application discloses a kind of radiation detector data fusion method and device, can realize the fusion of data between multiple detectors, to obtain the specific activity of concerned nuclide.Response calibration factor between different detectors is used, which can ensure that the relative detection effect of each detector on the same object to be measured is consistent, facilitating the composite measurement of the detector system.Meanwhile, combined with the method, composite measurement using a large-area plastic scintillator detector and a sodium iodide detector can be achieved, effectively combining the higher detection efficiency of the large-area plastic scintillator detector and the nuclide identification feature of the sodium iodide detector, which can distinguish the count rate by nuclide based on the collected data under the premise of ensuring a certain sorting efficiency.

Description

Technical Field

[0001] This invention relates to the field of radioactive monitoring technology, and in particular to a method and apparatus for data fusion of radiation detectors. Background Technology

[0002] Radiation poses a serious threat to human health. High doses of radiation can severely damage humans and animals. For example, at 400 rads (radia absorption intensity units), 5% of those exposed will die; at 650 rads, the mortality rate is 100%. Even at doses below 150 rads, the mortality rate is zero, but damage is not without its effects; symptoms often appear only after 20 years. Radiation can also damage genetic material, primarily by causing gene mutations and chromosomal aberrations, harming one or even several generations.

[0003] Monitoring radioactive materials is an important aspect of environmental radioactive pollution monitoring. Radioactive material detection and sorting systems often use detectors such as plastic scintillator detectors and sodium iodide detectors when conducting radioactive monitoring.

[0004] Although plastic scintillator detectors have a fast measurement time, their energy resolution is poor, making them unable to identify nuclides and failing to meet the requirements of radioactive material detection and sorting systems. Therefore, it is also necessary to configure detectors such as sodium iodide detectors that can identify nuclides.

[0005] Sodium iodide detectors have a relatively long nuclide identification time. If only sodium iodide detectors are used, multiple sodium iodide detectors are needed to obtain better measurement results in a shorter time. However, since large-volume sodium iodide is expensive, the method of using multiple sodium iodide detectors is costly and does not have advantages in engineering applications and commercial promotion.

[0006] To address the aforementioned issues, improve the detection efficiency of the detection system, and reduce the minimum detectable activity, a combined measurement method using two large-area plastic scintillator detectors and one sodium iodide detector can be employed. This effectively combines the high detection efficiency of the large-area plastic scintillator detector with the nuclide identification capability of the sodium iodide detector, enabling the collected data to be differentiated by nuclide count rate while maintaining a certain sorting efficiency. This radiation detection system consists of three detectors, and the measurement data from these three detectors needs to be fused to obtain the specific activity of each nuclide in the radioactive material. Since the three detectors are composed of two different types of detectors, and different types of detectors have different detection efficiencies for gamma rays of different energies, this factor needs to be considered when fusing data from the sodium iodide detector and the plastic scintillator detector, requiring the measurement of response calibration factors between the different detectors.

[0007] Therefore, how to provide a data fusion method to achieve data fusion of different types of detectors is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of the above problems, the present invention provides a radiation detector data fusion method and apparatus for overcoming or at least partially solving the above problems.

[0009] This invention provides the following solution:

[0010] A radiation detector data fusion method, comprising:

[0011] Obtain the first background count rate collected by the first detector;

[0012] Obtain the total radiation count rate of the radioactive material collected by the second detector;

[0013] The second background count rate of the second detector is calculated by combining the first background count rate with the first response calibration factor between the first detector and the second detector.

[0014] The net radiation count rate of the radioactive material is calculated using the second background count rate and the total radiation count rate.

[0015] Obtain the full-energy front count for each nuclide of interest collected by the third detector;

[0016] The net count ratio of each nuclide of interest in the second detector is calculated by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector.

[0017] The nuclide net count rate for each of the nuclides of interest is calculated using the net count ratio and the radiation net count rate.

[0018] The specific activity of each nuclide of interest is calculated using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide of interest.

[0019] Preferably, the first detector and the second detector are plastic scintillator type radiation detectors or gas-filled type radiation detectors of the same specifications; the third detector is a radiation detector that can be used for energy spectrum analysis, such as sodium iodide, lanthanum bromide, or high-purity germanium.

[0020] Preferably: the first detector is disposed above the upper surface of the conveyor belt and at the front end of the feed hopper; the second detector is disposed above the upper surface of the conveyor belt and at the rear end of the feed hopper; and the third detector is disposed above the upper surface of the conveyor belt and at the rear end of the second detector.

[0021] Preferably, both the first background count rate and the total radiation count rate are obtained by smoothing the current measured data using preceding data combined with the current measured data.

[0022] Preferably, both the first background count rate and the total radiation count rate are obtained by the following formula:

[0023]

[0024] In the formula: D k For the count rate of the radioactive material block labeled k, D' k (k = 1, 2, 3...) represents the current measured data, S a It is a sliding window.

[0025] Preferably, the net radiation count rate is calculated using the following formula:

[0026]

[0027] In the formula: D is the net radiation count rate. 2k D is the total radiation count rate. 1kb C1 and C1′ are the first background count rate, and C1 and C1′ are the first response calibration factors. Natural nuclides in radioactive materials 40 The count rate of K.

[0028] Preferably, the net count ratio is calculated using the following formula:

[0029]

[0030] In the formula: C is the net count ratio. 23i C 23i ′(i=1,2,3...z) is the second response calibration factor of the i-th nuclide between the second detector and the third detector.

[0031] Preferably, the net count rate of the nuclide is calculated using the following formula:

[0032]

[0033] In the formula: Let i be the net nuclide count rate. Net count rate This represents the net count ratio of the i-th nuclide. It is the sum of the net count ratios.

[0034] Preferably, the specific activity of the nuclide of interest is calculated using the following formula:

[0035]

[0036] Where: M ki For the i-th nuclide in radioactive material block L k Specific activity of radioactivity, A ki For the i-th nuclide in radioactive material block L k Total activity in m k For radioactive material block L k quality For the calculated radioactive material block L k The net count rate of the i-th nuclide, F ti is the specific activity conversion factor of the second detector for the i-th nuclide.

[0037] A radiation detector data fusion device, comprising:

[0038] The first background count rate acquisition unit is used to acquire the first background count rate collected by the first detector.

[0039] The total count rate acquisition unit is used to acquire the total count rate of radioactive materials collected by the second detector;

[0040] The second background count rate calculation unit is used to calculate the second background count rate of the second detector by combining the first background count rate with the first response calibration factor between the first detector and the second detector.

[0041] A radioactive material net count rate calculation unit is used to calculate the radioactive material net count rate using the second background count rate and the total radiation count rate.

[0042] The omnipotent front count acquisition unit is used to acquire the omnipotent front count of each nuclide of interest collected by the third detector;

[0043] The net count ratio acquisition unit is used to calculate the net count ratio of each nuclide of interest in the second detector by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector.

[0044] The nuclide net count rate acquisition unit is used to calculate the nuclide net count rate for each of the nuclides of interest using the net count ratio and the radioactive material net count rate;

[0045] The specific activity calculation unit for the nuclide is used to calculate the specific activity of each nuclide using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide.

[0046] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0047] This application provides a radiation detector data fusion method and apparatus that can fuse data from multiple detectors to obtain the specific activity of nuclides of interest. By employing response calibration factors between different detectors, the relative detection effects of each detector on the same analyte can be ensured to be consistent, facilitating composite measurements of the detector system. Furthermore, this method enables composite measurements using a large-area plastic scintillator detector and a sodium iodide detector. This effectively combines the high detection efficiency of the large-area plastic scintillator detector with the nuclide identification capability of the sodium iodide detector, allowing for the differentiation of collected data based on nuclide count rates while maintaining a certain sorting efficiency.

[0048] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0050] Figure 1 This is a flowchart of a radiation detector data fusion method provided in an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram illustrating the relationship between the maximum speed of the conveyor belt and the thickness of the radioactive material provided in an embodiment of the present invention;

[0052] Figure 3 This is a schematic diagram of the transmission of radioactive material provided in an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the detection system layout provided in an embodiment of the present invention;

[0054] Figure 5 This is a schematic diagram of the measurement surface of the detection system provided in an embodiment of the present invention;

[0055] Figure 6 This is a schematic diagram illustrating the principle of radioactive material measurement and calculation provided in an embodiment of the present invention;

[0056] Figure 7 This is a schematic diagram of the division of radioactive material blocks provided in an embodiment of the present invention;

[0057] Figure 8 The radioactive material block provided in this embodiment of the invention moves forward. Schematic diagram of the measurement afterwards;

[0058] Figure 9 This is a schematic diagram of radiation measurement smoothing of a radioactive material block provided in an embodiment of the present invention;

[0059] Figure 10 This is a schematic diagram of a radiation detector data fusion device provided in an embodiment of the present invention;

[0060] Figure 11 This is a schematic diagram of a radiation detector data fusion device provided in an embodiment of the present invention. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0062] See Figure 1 This invention provides a radiation detector data fusion method, such as... Figure 1 As shown, the method may include:

[0063] S101: Obtain the first background count rate collected by the first detector;

[0064] S102: Obtain the total count rate of radioactive materials collected by the second detector;

[0065] S103: Calculate the second background count rate of the second detector by combining the first background count rate with the first response calibration factor between the first detector and the second detector;

[0066] S104: The net count rate of the radioactive material is calculated using the second background count rate and the total radiation count rate; specifically, the net count rate of the radioactive material is calculated using the following formula:

[0067]

[0068] In the formula: D is the net count rate of radioactive materials. 2k D is the total radiation count rate.1k C1 and C1′ are the first background count rate, and C1 and C1′ are the first response calibration factors. Natural nuclides in radioactive materials 40 The count rate of K.

[0069] S105: Obtain the full-energy front count for each nuclide of interest collected by the third detector;

[0070] S106: The net count ratio of each nuclide of interest in the second detector is calculated using the full-energy front count combined with the second response calibration factor of each nuclide of interest between the second detector and the third detector; specifically, the net count ratio is calculated using the following formula:

[0071]

[0072] In the formula: C is the net count ratio. 23i C 23i ′(i=1,2,3...z) is the second response calibration factor of the i-th nuclide between the second detector and the third detector.

[0073] S107: The nuclide net count rate for each of the nuclides of interest is calculated using the net count ratio and the radiation net count rate; specifically, the nuclide net count rate is calculated using the following formula:

[0074]

[0075] In the formula: Let i be the net nuclide count rate. The net count rate of radioactive material radiation. is the net count ratio of the i-th nuclide.

[0076] S108: The specific activity of each nuclide of interest is calculated using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide of interest. Specifically, the specific activity of the nuclide of interest is calculated using the following formula:

[0077]

[0078] Where: M ki For the i-th nuclide in radioactive material block L k Specific activity of radioactivity, A ki For the i-th nuclide in radioactive material block L k Total activity in m k For radioactive material block L k quality For the calculated radioactive material block Lk The net count rate of the i-th nuclide, F ti is the specific activity conversion factor of the second detector for the i-th nuclide.

[0079] The radiation detector data fusion method provided in this application embodiment can fuse measurement data from three detectors to obtain the specific activity of each nuclide in a radioactive material. It can distinguish the collected data according to the count rate of nuclides while ensuring a certain sorting efficiency.

[0080] The method provided in this application is applicable to a radioactive material radiation detection system comprising three detectors. Specifically, the first and second detectors are plastic scintillator detectors of the same specifications; the third detector is a sodium iodide detector. Further, the first detector is positioned above the upper surface of the radioactive material conveyor belt and at the front end of the feed hopper; the second detector is positioned above the upper surface of the radioactive material conveyor belt and at the rear end of the feed hopper; and the third detector is positioned above the upper surface of the radioactive material conveyor belt and at the rear end of the second detector. This detection system will be described in detail later.

[0081] The method provided in this application embodiment can map the information on the type of nuclide and the activity ratio of each nuclide to the measurement count of the plastic scintillator detector. The specific activity of each nuclide can then be measured using the plastic scintillator detector, thereby meeting the system measurement requirements. Moreover, only one sodium iodide detector is used, which improves the measurement speed and reduces the cost.

[0082] To improve robustness and suppress statistical fluctuations, real-time measurements are generally not used directly as the basis for judgment. Instead, the current data is smoothed based on preceding real-time data. Specifically, embodiments of this application may provide that both the first background count rate and the total radiation count rate are obtained by smoothing the current measured data using preceding data combined with the current measured data.

[0083] Furthermore, both the first background count rate and the total radiation count rate are obtained using the following formula:

[0084]

[0085] In the formula: D k For the count rate of the radioactive material block labeled k, D is taken as follows: k '(k=1,2,3...) represents the current measured data, S a It is a sliding window.

[0086] The following describes the detection of radioactive materials under the condition that the detection efficiency reaches 120 t / h. 137Taking a radiation detection system with a minimum detectable activity (MDA) of 100 Bq / kg as an example, the radiation detector data fusion method provided in this application embodiment will be described in detail.

[0087] Under the condition that the detection efficiency of radioactive materials reaches 120 t / h, the radiation detection system can detect radioactive materials... 137 The minimum detectable activity (MDA) of Cs must reach 100 Bq / kg.

[0088] The detection area of ​​the plastic scintillator detector is chosen to be 100cm × 50cm. The width of the radioactive material carried by the radioactive material conveyor belt is also 100cm, meaning the width of the conveyor belt is equal to the length of the plastic scintillator, both being 1m. The length of the plastic scintillator detector in the direction of radioactive material transport is 50cm. Then, the sorting efficiency m (t / h) of the radioactive material depends on the thickness h (cm) of the radioactive material, the speed v (m / s) of the conveyor belt, and the density ρ (g / cm³) of the radioactive material. 3 The relationship between them is:

[0089]

[0090] The density of loose radioactive material is generally around 0.5 g / cm³. 3 ~1.8g / cm 3 In this embodiment, the density of the radioactive material is 1.5 g / cm³. 3 Then the above equation becomes:

[0091] m=54vh (2)

[0092] If the sorting efficiency m of radioactive materials reaches 120 tons / hour, then the relationship between the thickness of the radioactive material and the maximum speed of the conveyor belt is as follows: Figure 2 As shown, the points selected in the design should fall within... Figure 2 The shaded area.

[0093] Assuming the thickness of the radioactive material on the conveyor belt is at most 7 cm, we can know from equation (2) that the minimum speed of the conveyor belt at this time is 0.32 m / s.

[0094] In the direction of conveyor belt transport, the length L of the radioactive material below the vertical shadow of the plastic scintillator is 0.5m, such as... Figure 3 As shown.

[0095] When using a plastic scintillator detector, its measuring surface should be as close as possible to the surface of the radioactive material being measured. Simultaneously, lead shielding should be used to ensure that the measuring area of ​​the detector on the radioactive material is also 100cm × 50cm. Similarly, a sodium iodide detector, through lead collimation, also ensures that its measuring area on the radioactive material is 100cm × 50cm.

[0096] Therefore, the time it takes for a radioactive substance at a certain point on the conveyor belt to pass through the detector's measurement area, i.e., the time each detector takes to measure the radioactivity at a certain point in the radioactive substance, is at most 1.56 seconds.

[0097] Low-cost composite detection analysis:

[0098] Since the response time of plastic scintillator detectors is very fast, usually on the nanosecond level, a measurement time of 1.56 seconds is relatively sufficient. A larger detection area and a longer measurement time are beneficial to reducing the minimum detectable activity of the detector. Therefore, a 100cm×50cm×5cm plastic scintillator detector can be configured in the radiation detection system. Since plastic scintillator detectors are relatively inexpensive, and in order to better perform background subtraction, another plastic scintillator detector of the same specifications can be used in the radiation detection system specifically for background measurement.

[0099] Although plastic scintillator detectors have fast measurement times, they have poor energy resolution and cannot identify nuclides, thus failing to meet system requirements. Therefore, in this embodiment, a sodium iodide detector is also required.

[0100] Sodium iodide detectors have a relatively long nuclide identification time. If only a sodium iodide detector is used, a good measurement result can be obtained within 1.56 seconds. Multiple sodium iodide detectors are needed for the same measurement. However, since large-volume sodium iodide is expensive, the method of using multiple sodium iodide detectors is costly and does not have advantages in engineering applications and commercial promotion.

[0101] In practical engineering applications, from a large-scale perspective, the distribution of nuclides in radioactive materials is generally continuous and relatively stable within a certain range. In actual construction, soil is continuously shoveled from the contaminated area and sent to the radioactive material detection and sorting system. Therefore, the distribution of nuclides in radioactive materials transported on the radioactive material conveyor belt is also relatively stable within a certain distance.

[0102] Assume the nuclide recognition time of the sodium iodide detector is t. I The distance the radioactive material travels on the conveyor belt during this time is (e.g.) Figure 3 For a radioactive material block of length l, then:

[0103] l = vt I (3)

[0104] If the distribution of nuclei in a radioactive material block of length l (l>L) is considered uniform, then a sodium iodide detector can detect the distribution of nuclei at time t. IWithin a short time, the information on the types of nuclides and the activity ratio of each nuclide in the radioactive material block can be measured. If the information on the types of nuclides and the activity ratio of each nuclide are mapped to the measurement count of the plastic scintillator detector, the specific activity of each nuclide can be measured using the plastic scintillator detector, thereby meeting the system measurement requirements. Moreover, only one sodium iodide detector is needed, which improves the measurement speed and reduces the cost.

[0105] Radiation detection system design:

[0106] Based on the above approach, the radiation detector array of the radioactive material detection and sorting system consists of three detectors: two identical plastic scintillator detectors (detector D1 and detector D2) and one sodium iodide (NaI) detector (detector D3). These detectors are all placed on the upper surface of the radioactive material conveyor belt, and the non-measuring surfaces of the detectors are shielded with lead. The layout of this series of detectors is as follows: Figure 4 As shown. This radiation detection system consists of three detectors. In actual use, the specific activity of each nuclide in the radioactive material can be obtained by fusing the measurement data from the three detectors.

[0107] Radioactive material is evenly spread onto the conveyor belt via a feed hopper and a thickness-adjusting baffle. The thickness of the radioactive material can be adjusted between 2-7 cm as needed. The conveyor belt is 1 m wide, and its maximum speed should be greater than 0.5 m / s. The measuring area of ​​each of the three detectors on the conveyor belt is 100 cm × 50 cm. Figure 5 As shown.

[0108] The D1 detector is placed at the front end of the feed hopper to measure the background pollution in the space and the background pollution on the conveyor belt in real time, and to monitor whether the pollution on the conveyor belt exceeds the standard.

[0109] The D3 detector detects and identifies nuclides of interest in radioactive materials and calculates the activity percentage of each nuclide.

[0110] The D2 detector, located at the rear of the feed hopper, measures the total radioactivity of the analyte. It fuses data with that of the D1 detector, effectively reducing background interference on the D2 detector's measurements. Simultaneously, it acquires the activity percentage information of the nuclides of interest measured by the D3 detector, and through correction and conversion, calculates in real-time the contribution ratio of the nuclides of interest in the net count rate of the D2 detector, ultimately calculating the total radioactivity of the nuclides of interest (e.g.,...) in the analyte. 137 The specific activity of Cs, such as Figure 6 As shown.

[0111] It is understood that the three detectors provided in this application embodiment consist of two different detectors. Since different types of detectors have different detection efficiencies for gamma rays of different energies, this factor needs to be considered when performing data fusion between the sodium iodide detector and the plastic scintillator detector. This requires measuring the conversion factor between the two detectors for different energy rays. Therefore, this application embodiment provides a radiation detector data fusion method for data fusion, which can be implemented in the following ways.

[0112] Acquisition of radioactivity measurement data of radioactive materials:

[0113] The length of the detector's detection surface along the direction of radioactive material transport is L = 50 cm. Assuming the conveyor belt speed is v1, the total measurement time of the detector along the direction of transport for a certain radioactive material perpendicular to a tangent is A. t = L / v1, assuming the detector update time (i.e., single measurement time) is R. t Then after each time R t Radioactive material moves forward a certain distance on a conveyor belt, denoted as . The radioactive material being measured within the detection surface below the detector can be divided into n equal parts according to the direction of transmission, with each small piece of radioactive material having a length of... but like Figure 7 As shown, solid areas represent contaminated radioactive materials, while hollow areas represent uncontaminated radioactive materials.

[0114] For the length in the detection surface is Each small piece of radioactive material, assuming its mass is m i (i = 1, 2, ..., n) (kg), with a specific activity of M. i (i = 1, 2, ..., n)(Bq / kg), assuming the detector measures a count rate of D for this small piece of radioactive material. i (i = 1, 2, ... n)(cps).

[0115] Then the radioactive material advances each time The detector can obtain a real-time measurement data D' k (k=1,2,3...)(cps), that is, the count rate of radioactive material measured by the detector in each real-time step:

[0116]

[0117] Then the value (D') k / n) refers to the real-time measurement data of the radioactive material fragment labeled k (but actually D k It also includes the radiation information of the following n-1 small radioactive material pieces), such as Figure 9 As shown.

[0118] exist Figure 9 In this state, a block of radioactive material with a length of L within the detection surface is labeled as L. k Then D' k That is, L k Real-time measurement data, such as the detector's first measurement value D'1. Figure 7 The count rate of a radioactive material block of length L, labeled L1, after passing through R t After a period of time, the radioactive material moved forward. Radioactive material block No. 1 is moved out of the measurement area, radioactive material block No. 2 reaches the boundary of the detector's measurement area, and at the same time, radioactive material block No. (n+1) enters the measurement area. The detector completes the second measurement, and the measured value D'2 is... Figure 8 The count rate of a radioactive material block L2 of length L and marked with 2.

[0119] To improve robustness and suppress statistical fluctuations, real-time measurements are generally not used directly as the basis for judgment. Instead, the current data is smoothed based on the preceding real-time data. Assuming the sliding window is S... a Then the current radioactive material block L k The values ​​of its radiation measurement data are obtained from formula (5), and the measurement diagram is shown below. Figure 9 As shown.

[0120]

[0121] Measured value D k It actually contains radiation information for n+Sa radioactive material blocks.

[0122] For the sodium iodide detector (D3), in practical applications, the value of n is related to the length of l in equation (3). The length of n small radioactive material blocks should be equal to the length of l. The data acquisition method is the same as above.

[0123] Each measurement time R t In the radiation detection system, each detector receives a measurement value D'. k and D k The system uses the measurements from each detector as follows:

[0124] For the D1 detector:

[0125] Using the last real-time measurement value D' 1k Monitor the working status of the detector;

[0126] Average measurement D 1k Measure the baseline and monitor the contamination of the conveyor belt.

[0127] For the D2 detector:

[0128] Using the last real-time measurement value D' 2k Monitor the working status of the detector;

[0129] Average measurement D 2k The level of radioactive contamination is measured after data is fused with data from other detectors.

[0130] For the D3 detector:

[0131] Using the last real-time measurement value D' 3k Monitor the working status of the detector;

[0132] Average measurement D 3k Used for analyzing the activity percentage of each nuclide in radioactive materials.

[0133] Measurement data fusion algorithm:

[0134] After the radiation detection system is started, by Figure 4 It can be seen that the radioactive material on the conveyor belt first passes through detector D2, and then through detector D3. Assume the time elapsed is t1 (k R units). t After that, the D2 detector detected radioactive material block L. k The radiation data is D 2k Meanwhile, the background data measured by the D1 detector is D 1k After time t2, the D3 detector detected radioactive material block L. k The radiation data is D 3k .

[0135] Data fusion of D1 and D2 detectors

[0136] The background is subtracted from the background by the D1 detector. Since both detectors are plastic scintillator detectors, their measurement responses to the same nuclide are consistent. However, due to differences in the crystals, photomultiplier tubes, nuclear electronics, etc., the background values ​​measured by the two detectors for the same environment may differ. This difference needs to be considered during data fusion.

[0137] The formula for calculating the net count rate of radioactive material measured by the D2 detector is as follows:

[0138]

[0139] in, The net count rate (cps) of radioactive material measured by the D2 detector; D 2k The total count rate (cps) of radioactive material measured by the D2 detector; D 2kb This is the background value (second background count rate) of the D2 detector.

[0140] The background value of detector D2 is given by detector D1:

[0141] D 2kb =C1D 1kb +C1′ (7)

[0142] Among them, D 1kb C1 is the background count rate (cps) (first background count rate) measured by detector D1, and C1 and C1′ are the response calibration factors (first response calibration factors) between detectors D1 and D2, used for equivalent calculation of the measured values ​​of detectors D1 and D2.

[0143] Combining equations (6) and (7), the net count rate of radioactive material measured by the D2 detector is:

[0144]

[0145] When the radioactive material contains only the nuclide of interest or other nuclides that are negligible, the specific activity value of the radioactive material can be obtained by calling the specific activity conversion factor of that nuclide relative to the D2 detector at different radioactive material thicknesses / densities.

[0146]

[0147] In the above formula, M k For radioactive material block L k The specific activity of radioactivity (Bq / g). A k For radioactive material block L k Total activity (Bq), m k For radioactive material block L k The mass (g), The radioactive material block L detected by the detector k Net count rate (cps), F t The specific activity conversion factor (g·cps / Bq) of the D2 detector for the nuclide of interest.

[0148] Data fusion between D2 and D3 detectors:

[0149] Because D2 and D3 detectors are different types, each detector has different detection efficiencies relative to the same energy rays of the same nuclide. Therefore, it is necessary to perform equivalent calibration on the two detectors under the same conditions for measuring the same nuclide.

[0150] D 2k =C 23 D 3k +C 23 ′ (10)

[0151] C 23 C 23′ is the response calibration factor (second response calibration factor) between the D2 and D3 detectors. The response calibration factor is generally different for each nuclide and needs to be measured experimentally according to the actual operating environment of the detector.

[0152] Generally, radioactive materials contain multiple nuclides. In such cases, a D3 detector is used to identify the nuclides and measure the activity percentage of each nuclide. This activity percentage information is then converted into the activity percentage of each nuclide within the total count rate of the radioactive material measured by a D2 detector. This allows for the calculation of the specific activity of each nuclide of interest within the radioactive material. Specific activity, also known as specific radioactivity, refers to the ratio of the radioactivity of a radioactive source to its mass; that is, the radioactivity of a particular nuclide per unit mass of the product. Different radioactive elements have different specific activities, and the type of radioactive element can be determined based on the specific activity value.

[0153] Assuming the radioactive material contains z nuclides, after acquiring the energy spectrum, the D3 detector obtains the total energy peak count D for each nuclide through spectral analysis. 3ki (i=1,2,3...z). By using the response calibration factor between the D2 and D3 detectors, the net count ratio of each nuclide in the D2 detector can be obtained, as shown in Equation (11).

[0154]

[0155] In equation 11 above, C 23i C 23i ′(i=1,2,3...z) is the response conversion factor of the i-th nuclide between detectors D2 and D3.

[0156] Therefore, the net count ratio of each nuclide in the net count rate of the D2 detector (i.e., the net count rate of each nuclide) can be calculated, as shown in equation (12):

[0157]

[0158] By combining the activity conversion factor of each nuclide relative to the D2 detector in the radioactive material, the specific activity of each nuclide in the tested radioactive material can be obtained, as shown in equation (13):

[0159]

[0160] In the above formula, M ki For the i-th nuclide in radioactive material block L k The specific activity of radioactivity (Bq / g) in A. ki For the i-th nuclide in radioactive material block L k Total activity (Bq), m kFor radioactive material block L k The mass (g), For the calculated radioactive material block L k The net count rate (cps) of the i-th nuclide, F ti denoted as the specific activity conversion factor (g·cps / Bq) of the D2 detector for the i-th nuclide.

[0161] Using equation (13), the natural nuclides in the tested radioactive material can be calculated. 40 The K content can be subtracted from the background of the D2 detector to further reduce the background, thereby reducing the minimum detectable activity (MDA) for detecting radioactive materials.

[0162] Assuming the measured 40 The count rate of K Then equation (8) becomes:

[0163]

[0164] The C1, C1′, and C values ​​used in the above calculation methods 23 C 23 The purpose of these parameters is to ensure that the relative detection effects of the three detectors on the same object are consistent, which facilitates composite measurement of the detector system. These values ​​can be obtained through experimental measurement.

[0165] F t The value is the specific activity conversion factor related to the detection efficiency of different nuclides in the D2 detector. Its value also varies when the thickness of the radioactive material is different. The value can be obtained by MCNP simulation calculation, and the simulation value is corrected by experiments in actual engineering applications.

[0166] In summary, the radiation detector data fusion method provided in this application can fuse data from multiple detectors to obtain the specific activity of nuclides of interest. Employing response calibration factors between different detectors ensures consistent relative detection effects of each detector on the same analyte, facilitating composite measurements of the detector system. Furthermore, this method enables composite measurements using a large-area plastic scintillator detector and a sodium iodide detector. This effectively combines the high detection efficiency of the large-area plastic scintillator detector with the nuclide identification capability of the sodium iodide detector, allowing for the differentiation of collected data based on nuclide count rates while maintaining a certain sorting efficiency.

[0167] See Figure 10 This application embodiment can also provide a radiation detector data fusion device, such as... Figure 10 As shown, the device may include:

[0168] The first background count rate acquisition unit 1001 is used to acquire the first background count rate collected by the first detector.

[0169] The total count rate acquisition unit 1002 is used to acquire the total count rate of radioactive materials collected by the second detector;

[0170] The second background count rate calculation unit 1003 is used to calculate the second background count rate of the second detector by combining the first background count rate with the first response calibration factor between the first detector and the second detector.

[0171] The radioactive material net count rate calculation unit 1004 is used to calculate the radioactive material net count rate using the second background count rate and the total radiation count rate.

[0172] The omnipotent front count acquisition unit 1005 is used to acquire the omnipotent front count of each nuclide of interest collected by the third detector.

[0173] The net count ratio acquisition unit 1006 is used to calculate the net count ratio of each nuclide of interest in the second detector by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector.

[0174] The nuclide net count rate acquisition unit 1007 is used to calculate the nuclide net count rate for each of the nuclides of interest using the net count ratio and the radioactive material net count rate.

[0175] The specific activity calculation unit 1008 for nuclides of interest is used to calculate the specific activity of each nuclide of interest using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide of interest.

[0176] This application embodiment can also provide a radiation detector data fusion device, the device including a processor and a memory:

[0177] The memory is used to store program code and transmit the program code to the processor;

[0178] The processor is used to execute the steps of the radiation detector data fusion method described above according to the instructions in the program code.

[0179] like Figure 11 As shown in the figure, a radiation detector data fusion device provided in this application embodiment may include: a processor 10, a memory 11, a communication interface 12, and a communication bus 13. The processor 10, memory 11, and communication interface 12 all communicate with each other through the communication bus 13.

[0180] In the embodiments of this application, the processor 10 may be a central processing unit (CPU), a neural network processing unit (NPU), an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices.

[0181] The processor 10 can call programs stored in the memory 11. Specifically, the processor 10 can execute operations in the embodiments of the radiation detector data fusion method.

[0182] The memory 11 is used to store one or more programs. The programs may include program code, which includes computer operation instructions. In this embodiment, the memory 11 stores at least a program for implementing the following functions:

[0183] Obtain the first background count rate collected by the first detector;

[0184] Obtain the total count rate of radioactive materials collected by the second detector;

[0185] The second background count rate of the second detector is calculated by combining the first background count rate with the first response calibration factor between the first detector and the second detector.

[0186] The net count rate of radioactive material is calculated using the second background count rate and the total radiation count rate.

[0187] Obtain the full-energy front count for each nuclide of interest collected by the third detector;

[0188] The net count ratio of each nuclide of interest in the second detector is calculated by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector.

[0189] The net count rate of each nuclide of interest is calculated using the net count ratio and the net count rate of radioactive materials.

[0190] The specific activity of each nuclide of interest is calculated using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide of interest.

[0191] In one possible implementation, the memory 11 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function (such as file creation or data read / write). The data storage area may store data created during use, such as initialization data.

[0192] In addition, memory 11 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device or other volatile solid-state storage device.

[0193] Communication interface 12 can be an interface for the communication module, used to connect with other devices or systems.

[0194] Of course, it should be noted that, Figure 11 The structure shown does not constitute a limitation on the radiation detector data fusion device in the embodiments of this application. In practical applications, the radiation detector data fusion device may include more than Figure 11 More or fewer components as shown, or combinations of certain components.

[0195] This application embodiment may also provide a computer-readable storage medium for storing program code for executing the steps of the radiation detector data fusion method described above.

[0196] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0197] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0198] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0199] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for data fusion from a radiation detector, characterized in that, include: Obtain the first background count rate collected by the first detector; Obtain the total radiation count rate of the radioactive material collected by the second detector; The second background count rate of the second detector is calculated by combining the first background count rate with the first response calibration factor between the first detector and the second detector. The net radiation count rate of the radioactive material is calculated using the second background count rate and the total radiation count rate. Obtain the full-energy front count for each nuclide of interest collected by the third detector; The net count ratio of each nuclide of interest in the second detector is calculated by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector. The nuclide net count rate for each of the nuclides of interest is calculated using the net count ratio and the radiation net count rate. The specific activity of each nuclide of interest is calculated using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide of interest.

2. The radiation detector data fusion method according to claim 1, characterized in that, The first detector and the second detector are plastic scintillator type radiation detectors or gas-filled type radiation detectors of the same specifications; the third detector is a radiation detector made of sodium iodide, lanthanum bromide, or high-purity germanium that can be used for energy spectrum analysis.

3. The radiation detector data fusion method according to claim 2, characterized in that, The first detector is positioned above the upper surface of the conveyor belt and at the front end of the feed hopper; the second detector is positioned above the upper surface of the conveyor belt and at the rear end of the feed hopper; and the third detector is positioned above the upper surface of the conveyor belt and at the rear end of the second detector.

4. The radiation detector data fusion method according to claim 1, characterized in that, Both the first background count rate and the total radiation count rate are obtained by smoothing the current measured data using preceding data combined with the current measured data.

5. The radiation detector data fusion method according to claim 4, characterized in that, Both the first background count rate and the total radiation count rate are obtained by the following formula: In the formula: To be marked as The count rate of the radioactive material block is taken as follows. This is based on current measured data. , S a It is a sliding window.

6. The radiation detector data fusion method according to claim 1, characterized in that, The net radiation count rate is calculated using the following formula: In the formula: The net radiation count rate, The total radiation count rate, The first background count rate, , As the first response calibration factor, Natural nuclides in radioactive materials 40 The count rate of K.

7. The radiation detector data fusion method according to claim 1, characterized in that, The net count ratio is calculated using the following formula: In the formula: This is the net count ratio. , It is the first A second response calibration factor for a nuclide between the second detector and the third detector. i =1,2,3... z .

8. The radiation detector data fusion method according to claim 1, characterized in that, The net count rate of the nuclide is calculated using the following formula: ， i =1,2,3... z In the formula: For the first i Net count rate of nuclides Net count rate For the first i The net count ratio of the nuclides It is the sum of the net count ratios.

9. The radiation detector data fusion method according to claim 1, characterized in that, The specific activity of the nuclide of interest is calculated using the following formula: ， i =1,2,3... z In the formula: For the first Nuclide in radioactive material block Specific activity of radioactivity in For the first Nuclide in radioactive material block Total activity in A block of radioactive material quality For the calculated radioactive material block The Middle Net count rate of the nuclides For the second detector to the first The specific activity conversion factor of a nuclide.

10. A radiation detector data fusion device, characterized in that, include: The first background count rate acquisition unit is used to acquire the first background count rate collected by the first detector. The total count rate acquisition unit is used to acquire the total radiation count rate of the radioactive material collected by the second detector; The second background count rate calculation unit is used to calculate the second background count rate of the second detector by combining the first background count rate with the first response calibration factor between the first detector and the second detector. A radioactive material net count rate calculation unit is used to calculate the radioactive material net count rate using the second background count rate and the total radiation count rate. The omnipotent front count acquisition unit is used to acquire the omnipotent front count of each nuclide of interest collected by the third detector; The net count ratio acquisition unit is used to calculate the net count ratio of each nuclide of interest in the second detector by combining the full-energy front count with the second response calibration factor of each nuclide of interest between the second detector and the third detector. The nuclide net count rate acquisition unit is used to calculate the nuclide net count rate for each of the nuclides of interest using the net count ratio and the radioactive material net count rate; The specific activity calculation unit for the nuclide is used to calculate the specific activity of each nuclide using the net count rate of the nuclide and the specific activity conversion factor of the second detector for each nuclide.

Images