A method and system for imaging radiation sources in complex radiation fields

Abstract

The present invention relates to the field of radiation detection technology, and discloses a method and system for radioactive source imaging in complex radiation fields. In the radioactive source imaging system, a physical shielding layer is arranged on the outer layer of the anti-coincidence detector to shield low-energy non-target particles from being incident on the anti-coincidence detector, so as to prevent the lower-energy particles to be detected from being shielded by the anti-coincidence detector and the misjudged invalid signals, thereby increasing the number of valid signals and improving the radiation detection effect. The physical shielding layer is used to shield and attenuate the incident radiation signal. As the thickness of the physical shielding layer increases, the radiation signal will experience different degrees of attenuation. The setting of the trigger threshold and the time window in the radioactive source imaging method are all based on the thickness setting of the physical shielding layer, and are dynamically adjusted to ensure the stability of the system under different shielding layer thicknesses and improve the accuracy of radiation detection. Through the combined action of electronic coincidence and physical shielding, non-target interference is effectively removed and the quality of radiation detection results is improved.

Description

Technical Field

[0001] The present invention relates to the field of radiation detection technology, and in particular to a method and system for imaging a radiation source in a complex radiation field. Background Art

[0002] The development of nuclear technology applications is of great significance in the fields of energy, medicine, security, etc. Since the birth of nuclear science, radiation detection technology has been an important tool for nuclear physics research. Early radiation detectors were mainly gas detectors and scintillation detectors, which were used to record parameters such as the energy, time, and position of radioactive particles. However, with the increasing demand for research, especially in complex radiation fields, the requirements for detectors are becoming higher and higher, requiring detectors to have higher sensitivity, better energy resolution, and stronger anti-interference capabilities. In complex radiation fields, the types of radiation sources and background signal interference increase significantly. Taking high-energy gamma rays as an example, their detection faces the challenges of background noise and signal ambiguity.

[0003] Considering that complex radiation fields usually contain high-intensity background radiation and multiple false signal events, these interference factors will significantly reduce the accuracy and efficiency of the detector. Coincidence and anti-coincidence are usually used as two complementary signal processing technologies to improve the signal-to-noise ratio of the detection system, distinguish target signals from background interference, or achieve identification of complex particles. Their combined application is of great value in nuclear physics experiments, astrophysical observations, medical imaging (such as PET) and other fields.

[0004] Only when the coincidence detector detects particles on the side facing the radiation source and other measurement surfaces do not detect particles, will the corresponding signal processing be performed to achieve imaging. Under this premise, when particle detection is performed in a complex radiation field by coincidence / anti-coincidence, there are both high-energy and low-energy scattered interference rays. Only when the coincidence detector detects particles on the side facing the radiation source and the anti-coincidence detector does not detect particles, will it be judged as a valid signal for subsequent imaging processing. Other cases are considered invalid signals and are not used for imaging processing. When the capacity of the particle to be detected in a complex radiation field is low, the physical shielding effect of the anti-coincidence detector prevents the particle from being detected by the measurement surface of the coincidence detector that is not facing the radiation source. This should be a valid signal that the coincidence detector needs to perform imaging processing. However, in this case, both the coincidence detector and the anti-coincidence detector can detect the particle, which is mistakenly regarded as an invalid signal and discarded, thereby reducing the amount of effective signals for imaging processing and reducing the accuracy of radiation monitoring effects.

[0005] Therefore, there is an urgent need for a radiation source imaging method and system for complex radiation fields that can accurately identify particles to be measured and improve radiation monitoring effects. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides, on one hand, a radioactive source imaging method for a complex radiation field, which is implemented based on a radioactive source imaging system, wherein the radioactive source imaging system comprises: a main detector, an anti-coincidence detector and a physical shielding layer; the physical shielding layer is a cover body with a front opening formed by surrounding side walls on four sides and the rear side, the physical shielding layer is a cavity for placing the main detector and the anti-coincidence detector, and the front end of the physical shielding layer is an opening, so that the particles to be detected emitted by the radioactive source in the complex radiation field can be directly detected by the main detector;

[0007] The radioactive source imaging method comprises the following steps:

[0008] S1: Amplify the signals detected by the main detector and the anti-coincidence detector respectively to obtain the amplified signals of the main detector and the anti-coincidence detector;

[0009] S2: Compare the amplified signals with the trigger thresholds respectively, and perform signal shaping processing only when the amplified signals are all greater than the trigger thresholds; the trigger thresholds are set according to the thickness of the physical shielding layer;

[0010] S3: performing signal shaping processing on the amplified signals of the main detector and the anti-coincidence detector respectively to obtain shaped signals of the main detector and the anti-coincidence detector;

[0011] S4: based on the shaped signals of the main detector and the anti-coincidence detector, respectively obtain the signal triggering time of the corresponding detector, and calculate the difference between the signal triggering time of the main detector and the anti-coincidence detector;

[0012] S5: When the difference between the signal triggering times does not exceed a preset time window, imaging is performed on the shaped signals of the main detector and the anti-coincidence detector; the time window is set according to the thickness of the physical shielding layer.

[0013] Through the logical design of the anti-coincidence circuit, the system performs dynamic time coincidence matching on the signals of the main detector and the anti-coincidence detector to ensure strict signal synchronization and effectively suppress the interference of false signals and background noise in complex radiation fields. The anti-coincidence circuit can perform logical analysis on the signals of the main detector and the anti-coincidence detector in real time and eliminate false events that do not conform to the laws of physics, thereby significantly improving detection efficiency and data purity.

[0014] Preferably, the calculation formula of the trigger threshold is:

[0015] ;

[0016] in, is the trigger threshold, is the initial trigger threshold, is the shielding attenuation coefficient, is the thickness of the physical shielding layer, is the initial shielding layer thickness.

[0017] Preferably, the calculation formula of the time window is:

[0018] ;

[0019] Where ΔT is the time window, ΔT0 is the initial time window, β is the time window adjustment coefficient, and d shield is the thickness of the physical shield.

[0020] Preferably, before S5, the step further includes performing CFD processing on the shaped signals of the main detector and the anti-coincidence detector respectively, and the formula is as follows:

[0021] ;

[0022] in, Represents the shaped signal, represents the signal after CFD processing, represents the CFD function, and A represents the amplitude of the signal.

[0023] Another aspect of the present invention provides a radiation source imaging system for a complex radiation field, which implements any of the above-mentioned radiation source imaging methods for a complex radiation field, wherein the radiation source imaging system comprises: a main detector, an anti-coincidence detector, a physical shielding layer and an anti-coincidence circuit;

[0024] The main detector and the anti-coincidence detector are respectively used to capture the signals of the particles to be detected;

[0025] The physical shielding layer is used to shield low-energy non-target particles from being incident on the anti-coincidence detector;

[0026] The anti-coincidence circuit is used to perform logic judgment on the particle signals to be detected captured by the main detector and the anti-coincidence detector to retain valid particle signals.

[0027] Preferably, the physical shielding layer is a high atomic number material.

[0028] Preferably, the detection layer in the main detector is LaBr3.

[0029] Preferably, the detection layer in the anti-coincidence detector is one of BGO and NaI.

[0030] The embodiments of the present invention have the following technical effects:

[0031] The radiation source imaging system provided by the present application sets a physical shielding layer on the outer layer of the anti-coincidence detector to shield low-energy non-target particles from being incident on the anti-coincidence detector, thereby preventing lower-energy particles to be detected from being shielded by the anti-coincidence detector and misjudging invalid signals, increasing the number of valid signals, and thus improving the radiation detection effect.

[0032] In addition, the function of the physical shielding layer is to shield and attenuate the incident radiation signal. As the thickness of the physical shielding layer increases, the radiation signal will experience different degrees of attenuation. Therefore, the trigger threshold and time window settings in the radiation source imaging method are dynamically adjusted based on the thickness setting of the physical shielding layer to ensure the stability of the system under different shielding layer thicknesses and improve the accuracy of radiation detection.

[0033] The present application effectively removes non-target interference and improves the quality of radiation detection results by means of the combined effects of electronic coincidence and physical shielding. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 is a structural schematic diagram of a radiation source imaging system for a complex radiation field provided by an embodiment of the present invention;

[0036] Figure 2 It is a flow chart of a method for imaging a radiation source in a complex radiation field provided by an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of the detailed structure of a radiation source imaging system for a complex radiation field provided by an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of the steps of a radiation source imaging method for a complex radiation field provided by an embodiment of the present invention.

[0039] 1. Main detector; 2. Anti-coincidence detector; 3. Physical shielding layer; 4. Anti-coincidence circuit. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0041] The present application provides a radioactive source imaging method for a complex radiation field, which is implemented based on a radioactive source imaging system, wherein the radioactive source imaging system comprises: a main detector 1, an anti-coincidence detector 2, and a physical shielding layer 3; the physical shielding layer 3 is a cover body with a front opening formed by surrounding side walls on four sides and a rear side, the physical shielding layer 3 is a cavity for placing the main detector 1 and the anti-coincidence detector 2, and the front end of the physical shielding layer 3 is an opening, so that the particles to be detected emitted by the radioactive source in the complex radiation field can be directly detected by the main detector 1;

[0042] Figure 4 is a schematic diagram of the steps of a radiation source imaging method for a complex radiation field provided by an embodiment of the present invention, Figure 2 is a flow chart of a method for imaging a radiation source in a complex radiation field provided by an embodiment of the present invention, such as Figure 2 and Figure 4 As shown, the radiation source imaging method includes the following steps:

[0043] S1: Amplify the signals detected by the main detector and the anti-coincidence detector respectively to obtain the amplified signals of the main detector and the anti-coincidence detector;

[0044] The radiation signal received by the detector is usually a relatively weak current pulse signal, which needs to be processed by signal amplification and shaping. In the signal amplification stage, the signal is initially amplified by the preamplifier. Assuming the input signal is , the signal output by the preamplifier is , then the signal amplification process can be expressed as:

[0045] ;

[0046] in, It is the gain of the preamplifier.

[0047] S2: Compare the amplified signals with the trigger thresholds respectively. Only when the amplified signals are greater than the trigger thresholds, signal shaping is performed; if they are not greater than the trigger thresholds, the signals are discarded and not processed. The trigger threshold is set according to the thickness of the physical shielding layer 3;

[0048] As the thickness of the physical shield changes, the trigger threshold adjusts accordingly, ensuring that the system can always effectively distinguish between the target particle signal and background noise. As the shield thickness increases, the trigger threshold also increases to accommodate signal attenuation and noise reduction. The thickness of the physical shield The relationship between can be expressed as the following formula:

[0049] ;

[0050] in, is the trigger threshold, is the initial trigger threshold, is the shielding attenuation coefficient, is the thickness of the physical shielding layer 3, is the initial shielding layer thickness.

[0051] S3: performing signal shaping processing on the amplified signals of the main detector and the anti-coincidence detector respectively to obtain shaped signals of the main detector and the anti-coincidence detector;

[0052] The amplified signal enters the pulse shaping circuit, and the signal is given a fixed time width and shape through Gaussian shaping or trapezoidal shaping.

[0053] S4: based on the shaped signals of the main detector and the anti-coincidence detector, respectively obtain the signal triggering time of the corresponding detector, and calculate the difference between the signal triggering time of the main detector and the anti-coincidence detector;

[0054] S5: When the difference in the triggering time of the signal does not exceed the preset time window, the shaped signals of the main detector and the anti-coincidence detector are imaged; if the difference in the triggering time of the signal is greater than or equal to the preset time window, the signal is discarded and not processed. The time window is set according to the thickness of the physical shielding layer 3.

[0055] The thickness change of the physical shielding layer will also affect the time window (ΔT) of the system. The increase of the physical shielding layer will reduce the interference ray content and cause signal propagation delay, thus affecting the time difference between signals. Therefore, the time window (ΔT) in the trigger logic needs to be adjusted according to the change of the shielding layer.

[0056] Adjust to ensure that the event time between detectors fits within the expected time window. For a specific shielding material, the effect of changes in the thickness of the physical shielding layer on the time window can be expressed by the following formula:

[0057] ;

[0058] Where ΔT is the time window, ΔT0 is the initial time window, β is the time window adjustment coefficient, and d shield is the thickness of the physical shielding layer 3.

[0059] As the thickness of the physical shielding layer increases, the time window will also increase to accommodate the delay in signal propagation, ensuring that the signals from the primary detector and the anti-coincidence detector can be judged as valid within a reasonable time frame.

[0060] Use a time-to-digital converter to record the time when the event occurs and calculate the time difference between the main detector and the anti-coincidence detector. Suppose the trigger time of the main detector is , the triggering time of the anti-coincidence detector is , then the time difference between them can be expressed as To ensure the validity of the signal, set a time window , only when the signals of the two detectors occur within this short time window, that is, They are considered to be related events.

[0061] After the imaging detector detects data1, the distribution of the radiation source under the complex radiation field is obtained through a reconstruction algorithm, which refers to the distribution of the radiation source in two-dimensional or three-dimensional space.

[0062] In this process, the input reconstruction input data includes:

[0063] Raw data (data1): This data contains various information about the detection event, including but not limited to the timestamp of the event, the location of the detector, the energy information of the scattering end and the absorption end, and the scattering angle data.

[0064] Parameter settings: including gamma ray energy, energy screening range, number of spatial resolution bins, and spatial coordinate range of the imaging area. Output data refers to the two-dimensional / three-dimensional spatial intensity distribution of the radiation source.

[0065] The reconstruction algorithms include direct back-projection, iterative algorithm, etc., which can be used directly and will not be described in detail here.

[0066] Through the coordinated work of the main detection layer and the anti-coincidence detection layer, as well as the logical judgment of the signal by the anti-coincidence circuit, the background signal can be efficiently eliminated. For example, when the background pseudo signal generates a response in both the main detection layer and the anti-coincidence detection layer, the anti-coincidence logic will identify it as a non-target event and exclude it, thereby significantly improving the purity of the signal and the accuracy of the measurement. This background suppression capability is particularly prominent in high-noise environments and is superior to many traditional single-layer detectors.

[0067] In some embodiments, due to the difference in the signal amplitude of the detectors, directly setting the trigger threshold may cause time jitter, affecting the accuracy of time determination. Therefore, before S5 of the present invention, the shaped signals of the main detector and the anti-coincidence detector are respectively subjected to CFD processing, and the formula is as follows:

[0068] ;

[0069] in, Represents the shaped signal, represents the signal after CFD processing, represents the CFD function, and A represents the amplitude of the signal.

[0070] Figure 1 is a schematic diagram of a structure of a radiation source imaging system for a complex radiation field provided by an embodiment of the present invention. The present invention also provides a radiation source imaging system for a complex radiation field, which implements any of the above-mentioned radiation source imaging methods for a complex radiation field, such as Figure 1 As shown, the radiation source imaging system comprises: a main detector 1, an anti-coincidence detector 2, a physical shielding layer 3 and an anti-coincidence circuit 4;

[0071] The main detector 1 includes, but is not limited to, Compton imaging and autocollimation imaging, etc. The spatial position and direction information of the radiation source can be obtained by combining Compton imaging technology, which is suitable for positioning and imaging of gamma-ray sources. At the same time, the system can also integrate autocollimation imaging technology to achieve accurate measurement of high-energy particle trajectories, thereby meeting the needs of particle kinematic characteristics analysis in nuclear reaction experiments. This flexible imaging function design makes it widely applicable under complex experimental conditions.

[0072] The main detector 1 and the anti-coincidence detector 2 are respectively used to capture the signals of the particles to be detected; the main detector 1 is used to record the energy signals of the particles to be detected, and the anti-coincidence detector 2 surrounds the main detector 1 and is used to detect scattered rays. This design can retain the signal events of full energy absorption, effectively improve the quality of the energy spectrum and has wide applicability. Through the coordinated design of the main detection layer and the anti-coincidence detection layer, and the efficient filtering ability of the anti-coincidence logic, it is possible to ensure that the detection performance remains stable in a strong interference environment. This makes it particularly suitable for tasks such as nuclear reactor monitoring, fission neutron spectrum measurement, and rapid positioning of radiation sources.

[0073] The main detection layer of the system is designed to capture target particle signals, while the auxiliary detection layer is used as an anti-coincidence layer to identify and eliminate background noise and other interfering signals. The signal captured by the detector is first amplified by a charge-sensitive preamplifier, and then processed by a signal comparison circuit and input into the anti-coincidence circuit for multi-level data processing. The core anti-coincidence mechanism can effectively distinguish target events from non-target events and reduce the impact of background noise on the detection results by comprehensively analyzing the signal characteristics of the main detection layer and the anti-coincidence layer. The final effective signal is transmitted to the data acquisition card for recording and subsequent analysis.

[0074] The physical shielding layer 3 is used to shield low-energy non-target particles from entering the anti-coincidence detector 2; in this application, the physical shielding is fully utilized to shield low-energy rays, so as to avoid interference with low-energy signals. Although the anti-coincidence detector 2 can also shield rays to a certain extent, high-energy rays have strong penetrability, so the anti-coincidence detector is mainly used for shielding to achieve a synergistic effect.

[0075] When setting the thickness of the physical shielding layer 3, the following factors related to the particle radiation scenario to be measured need to be considered comprehensively:

[0076] (1) Energy of the particle to be measured

[0077] High-energy target particles have strong penetrating power, so it is necessary to ensure that the thickness of the shielding layer can effectively shield low-energy non-target particles while not excessively attenuating the signal of the target particles. For example, if the particles to be detected are high-energy gamma rays, it is necessary to select a shielding material of appropriate thickness to block low-energy scattered photons while allowing high-energy target particles to penetrate to the main detector.

[0078] (2) Complexity of the radiation field

[0079] Including the types, energy distribution and intensity of interfering particles in the environment. If the background radiation is complex (such as the coexistence of multiple types of radiation sources), the thickness of the shielding layer needs to be increased to enhance the filtering ability of low-energy interference, but it needs to be balanced with the signal attenuation effect.

[0080] (3) Characteristics of shielding materials

[0081] The atomic number, density and attenuation coefficient of the material directly affect the shielding efficiency. Materials with high atomic numbers (such as lead and tungsten) are more effective in shielding low-energy particles and can reduce the required thickness; while low-density materials may require a thicker shielding layer to achieve the same effect.

[0082] (4) Relationship between signal attenuation and trigger threshold

[0083] The increase of the shielding layer will cause the target particle signal to attenuate, and the trigger threshold needs to be dynamically adjusted to match the signal strength. The quantitative relationship between shielding thickness and signal attenuation needs to be determined through experiments or theoretical models to ensure that the effective signal is not misjudged as noise.

[0084] (5) Matching of time windows

[0085] The increase in shielding layer thickness may introduce signal propagation delay, and the time window (ΔT) needs to be adjusted to compensate for the time difference between the main detector and the anti-coincidence detector to avoid the effective signal being mistakenly rejected due to the delay.

[0086] (6) System portability and cost

[0087] A shielding layer that is too thick will increase system weight and manufacturing costs. The shielding effect and practicality must be weighed based on the actual application scenario (such as laboratory fixed equipment or field mobile equipment).

[0088] (7) Thermodynamic and mechanical stability

[0089] The thickness of the shielding material must meet the mechanical strength requirements and take into account the heat dissipation needs (such as the heat that may be generated in a high radiation environment) to avoid affecting the detector performance due to temperature changes.

[0090] For example, if the particle to be detected is a 1 MeV gamma ray, and there are a large number of low-energy scattered photons (such as 0.2 MeV) in the radiation field, when lead (a high atomic number material) is used as a shielding layer, the thickness can be set to 5 mm to effectively shield low-energy interference while ensuring that the 1 MeV gamma signal attenuation is within an acceptable range (such as <10%). At this time, the trigger threshold and time window need to be dynamically calibrated according to the attenuation coefficient and delay characteristics of the 5 mm lead layer to optimize the signal-to-noise ratio and detection efficiency.

[0091] The function of the physical shielding layer is to attenuate the incident radiation signal. As the thickness of the physical shielding layer increases, the radiation signal will experience different degrees of attenuation. Therefore, the trigger threshold and time window need to be dynamically adjusted to ensure the stability of the system under different shielding layer thicknesses.

[0092] The anti-coincidence circuit 4 is used to perform logic judgment on the particle signals to be detected captured by the main detector 1 and the anti-coincidence detector 2 to retain valid particle signals.

[0093] like Figure 3As shown in the figure, in the anti-coincidence layer, the auxiliary detector is used to detect the scattered signal of high-energy photons. Its structural design is a layout mode in which the main detection layer is surrounded by the anti-coincidence detection layer. This design can shield external interference and enhance the selectivity of the system. The output pulse signal is first amplified into a voltage signal by the charge sensitive preamplifier circuit, and then the signal amplitude is judged by the threshold signal comparison module, the signal outside the threshold interval is shielded, and the effective scattered signal that meets the requirements is screened out. The processing result of the quality threshold signal is sent to the anti-coincidence circuit, in which a logical operation is performed with the signal of the main detector of the measurement layer. Through the linkage control of the anti-coincidence circuit, the output signal of the auxiliary detector is strictly matched with the main detector signal in the time domain, thereby suppressing the interference of invalid scattered signals on the measurement accuracy. In the measurement layer, the main detector is responsible for receiving the incident high-energy photon signal, and the pulse signal generated by it is processed by the charge sensitive preamplifier circuit and converted into a voltage signal proportional to the energy of the incident photon. The energy signal of the main detector is directly transmitted to the anti-coincidence circuit, waiting for logical comparison with the scattered signal provided by the anti-coincidence layer. During the whole process, the power module provides stable power support for the main and auxiliary detectors and their signal amplification circuits to ensure the output accuracy and stability of the energy signal. In the whole system, the anti-coincidence circuit completes the logic and operation by receiving the scattered signal of the anti-coincidence layer and the energy signal of the measurement layer to screen out the background events. By matching the time information of the two signals, the system can effectively eliminate the interference signals that do not conform to the expected physical events. Finally, the output signal of the anti-coincidence circuit is transmitted to the data acquisition card to realize the digital storage and subsequent analysis and processing of the signal. This technical design realizes the linkage screening of the main detection signal and the scattered signal, increases the proportion of effective events, greatly improves the background suppression capability and data quality of the detection system, and lays the foundation for the accurate acquisition of high-energy photon information.

[0094] In some embodiments, the physical shielding layer 3 is a high atomic number material. Adding a physical shielding layer requires consideration of factors such as location, material, structure, and economy and portability. After comprehensive consideration, this patent uses: high atomic number materials, tungsten / lead and their alloys, etc., which are placed between the two detectors to achieve a synergistic shielding effect and are more economical and portable.

[0095] For example, with modular design, different detection materials can be flexibly selected for the main detection layer and the anti-coincidence detection layer according to experimental requirements. This flexibility enables the technology to cover a wider energy range and be applicable to a variety of complex radiation field environments, including high-energy particle physics experiments, nuclear security, and industrial non-destructive testing.

[0096] In some embodiments, the detection layer in the main detector 1 is LaBr3.

[0097] In some embodiments, the detection layer in the anti-coincidence detector 2 includes but is not limited to BGO, NaI (sodium iodide), LaBr3 (lanthanum bromide) scintillation detectors, and semiconductor-based SiPM (silicon photomultiplier) or HPGe (high purity germanium detector). These detector materials and structures can be selected according to experimental requirements to meet the requirements of detection sensitivity, energy resolution, and time resolution, ensuring that optimal performance can be achieved under different radiation field conditions.

[0098] Another aspect of the present invention further provides a device, comprising a processor and a memory:

[0099] The memory is used to store a computing execution program of any one of the above-mentioned radioactive source imaging methods for complex radiation fields;

[0100] The processor is used to retrieve the calculation execution program from the memory and execute a radiation source imaging method for a complex radiation field.

[0101] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0102] The memory may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor may run the program instructions to implement a method for imaging a radioactive source for a complex radiation field and / or other desired functions of any embodiment of the present application described above. Various contents such as initial external parameters, thresholds, etc. may also be stored in the computer-readable storage medium.

[0103] In one example, the electronic device may further include: an input device and an output device, and these components are interconnected through a bus system and / or other forms of connection mechanisms (not shown). The input device may include, for example, a keyboard, a mouse, etc. The output device may output various information to the outside, including early warning information, braking force, etc. The output device may include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, etc.

[0104] Of course, for the sake of simplicity, components such as buses, input / output interfaces, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0105] In addition to the above-mentioned methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to implement the functions of a radiation source imaging method for a complex radiation field provided by any embodiment of the present application.

[0106] The computer program product may be written in any combination of one or more programming languages ​​to write program codes for performing the operations of the embodiments of the present application, including object-oriented programming languages, such as Java, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0107] Another aspect of the present invention provides a storage medium storing a computer execution program, wherein the computer execution program is called by a processor to execute the steps of any one of the above-mentioned methods for imaging a radiation source in a complex radiation field.

[0108] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for imaging a radioactive source in a complex radiation field, characterized in that: The radioactive source imaging method is implemented based on a radioactive source imaging system, the radioactive source imaging system comprising: a main detector (1), an anti-coincidence detector (2) and a physical shielding layer (3); the physical shielding layer (3) is a cover body with a front opening formed by four sides and a rear side wall, the physical shielding layer (3) contains a cavity for placing the main detector (1) and the anti-coincidence detector (2), and the front end of the physical shielding layer (3) is an opening, so that the particles to be detected emitted by the radioactive source in a complex radiation field can be directly detected by the main detector (1); The radioactive source imaging method comprises the following steps: S1: Amplify the signals detected by the main detector and the anti-coincidence detector respectively to obtain the amplified signals of the main detector and the anti-coincidence detector; S2: comparing the amplified signals with the trigger thresholds respectively, and performing signal shaping processing only when the amplified signals are all greater than the trigger thresholds; the trigger thresholds are set according to the thickness of the physical shielding layer (3); S3: performing signal shaping processing on the amplified signals of the main detector and the anti-coincidence detector respectively to obtain shaped signals of the main detector and the anti-coincidence detector; S4: based on the shaped signals of the main detector and the anti-coincidence detector, respectively obtain the signal triggering time of the corresponding detector, and calculate the difference between the signal triggering time of the main detector and the anti-coincidence detector; S5: When the difference between the signal triggering times does not exceed a preset time window, imaging processing is performed on the shaped signals of the main detector and the anti-coincidence detector; the time window is set according to the thickness of the physical shielding layer (3).

2. A method for imaging a radiation source in a complex radiation field according to claim 1, characterized in that: The calculation formula of the trigger threshold is: ； in, is the trigger threshold, is the initial trigger threshold, is the shielding attenuation coefficient, is the thickness of the physical shielding layer (3), is the initial shielding layer thickness.

3. A method for imaging a radiation source in a complex radiation field according to claim 1, characterized in that: The calculation formula of the time window is: ； Where ΔT is the time window, ΔT0 is the initial time window, β is the time window adjustment coefficient, and d shield is the thickness of the physical shielding layer (3).

4. A method for imaging a radiation source in a complex radiation field according to claim 1, characterized in that: Before S5, the shaped signals of the main detector and the anti-coincidence detector are processed by CFD respectively, and the formula is as follows: ； in, Represents the shaped signal, represents the signal after CFD processing, represents the CFD function, and A represents the amplitude of the signal.

5. A radiation source imaging system for complex radiation fields, implementing a radiation source imaging method for complex radiation fields as claimed in any one of claims 1 to 4, characterized in that: The radioactive source imaging system comprises: a main detector (1), an anti-coincidence detector (2), a physical shielding layer (3) and an anti-coincidence circuit (4); The main detector (1) and the anti-coincidence detector (2) are respectively used to capture the signals of the particles to be detected; The physical shielding layer (3) is used to shield low-energy non-target particles from being incident on the anti-coincidence detector (2); The anti-coincidence circuit (4) is used to perform logic judgment on the particle signals to be detected captured by the main detector (1) and the anti-coincidence detector (2), so as to retain valid particle signals.

6. A radiation source imaging system for complex radiation fields according to claim 5, characterized in that: The physical shielding layer (3) is made of a high atomic number material.

7. A radiation source imaging system for complex radiation fields according to claim 5, characterized in that: The detection layer in the main detector (1) is LaBr3.

8. The radiation source imaging system for complex radiation fields according to claim 5, characterized in that: The detection layer in the anti-coincidence detector (2) is one of BGO and NaI.

Images