An underwater array radiation detector

Abstract

The present invention relates to the field of underwater detector technology and discloses an underwater array radiation detector comprising a metal bracket, at least one NaI (Tl) crystal detector, and at least one CeBr3 crystal detector. The NaI (Tl) crystal detector and the CeBr3 crystal detector are fixed within the first metal bracket; a metal protective mesh is provided outside the NaI (Tl) crystal detector and the CeBr3 crystal detector. The present invention improves detection efficiency and speed, enhances energy resolution, strengthens anti-interference capabilities, and enhances the detector's adaptability. It also enables mobile radiation monitoring and is suitable for radiation monitoring tasks in a variety of complex environments.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater detectors, and in particular to an underwater array radiation detector. Background Art

[0002] An underwater detector is a device designed to operate underwater, used to detect, monitor, and record underwater information. It plays an important role in marine science research, environmental monitoring, resource exploration, and other fields, particularly in radiation detection.

[0003] In existing technologies, NaI(Tl) (sodium iodide doped thallium) crystal detectors or CeBr3 (cerium bromide) crystal detectors are commonly used as underwater detectors. However, current underwater detectors rely solely on NaI(Tl) or CeBr3 crystal detectors. NaI(Tl) crystal detectors have relatively poor energy resolution, resulting in poor detection performance in applications requiring high resolution. CeBr3 crystal detectors also have low detection efficiency, and using only CeBr3 crystal detectors reduces this efficiency, impacting radiation monitoring tasks. Furthermore, NaI(Tl) and CeBr3 crystals are fragile and prone to breakage while moving underwater, limiting existing NaI(Tl) or CeBr3 crystal detectors to fixed-point monitoring.

[0004] Therefore, there is an urgent need for an underwater array radiation detector that can improve detection efficiency and speed, improve energy resolution, enhance anti-interference ability, enhance the adaptability of the detector, and be able to perform mobile radiation monitoring, which can be applied to radiation monitoring tasks in a variety of complex environments. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an underwater array radiation detector, which can improve detection efficiency and detection speed, improve energy resolution, enhance anti-interference ability, enhance the adaptability of the detector, and can also perform mobile radiation monitoring. It can be applied to radiation monitoring tasks in a variety of complex environments.

[0006] The present invention provides an underwater array radiation detector, comprising:

[0007] a first metal support, at least one NaI(Tl) crystal detector and at least one CeBr3 crystal detector;

[0008] The NaI crystal detector and the CeBr3 crystal detector are fixed inside the first metal bracket.

[0009] Furthermore, the number of NaI (Tl) crystal detectors is 3, and the number of CeBr3 crystal detectors is 1.

[0010] Furthermore, the NaI(Tl) crystal detector is a cylinder with a diameter of 3 inches and a length of 6 inches, and the CeBr3 crystal detector is a cylinder with a diameter of 2 inches and a length of 2 inches.

[0011] Furthermore, the NaI (Tl) crystal detectors are arranged in a circumferential direction, and the distance between two adjacent NaI (Tl) crystal detectors in the circumferential direction is 30 cm.

[0012] Furthermore, the NaI (Tl) crystal detector is arranged around the periphery of the CeBr3 crystal detector.

[0013] Furthermore, the crystal detector includes: spectrometer electronics, GM counter tube, aluminum alloy bracket and detection crystal;

[0014] The spectrometer electronics, GM counter tube and detection crystal are fixed on the aluminum alloy bracket in sequence;

[0015] The detection crystal is NaI (Tl) crystal or CeBr3 crystal.

[0016] Furthermore, it also includes a metal protective net, which is arranged on the outside of the NaI (Tl) crystal detector and the CeBr3 crystal detector to protect the NaI (Tl) crystal detector and the CeBr3 crystal detector.

[0017] Furthermore, it also includes a second metal bracket and a triangle plate;

[0018] The second metal bracket is fixed on the upper side of the triangle plate and is used to fix the underwater array radiation detector to the monitoring platform;

[0019] The first metal bracket is fixed to the lower side of the triangle plate, and the first metal bracket is used to fix the NaI (Tl) crystal detector and the CeBr3 crystal detector on the triangle plate.

[0020] The embodiments of the present invention have the following technical effects:

[0021] The present invention combines NaI (Tl) crystal detectors and CeBr3 crystal detectors to form an underwater array radiation detector. It combines the advantages of high detection efficiency of NaI (Tl) crystal detectors and good energy resolution of CeBr3 crystal detectors, and designs parameters such as the number, size, spacing, and arrangement of NaI (Tl) crystal detectors and CeBr3 crystal detectors. This can cover a wider energy range, improve the detection sensitivity to different types of radiation, and enhance the detection efficiency and energy resolution of the entire system. Mobile radiation detection also requires high detection efficiency to meet this requirement.

[0022] By combining multiple detectors to work simultaneously, the present invention can provide data redundancy. Even if a detector fails, the other detectors can continue to operate, ensuring data continuity and reliability. CeBr3 crystals have a relatively fast scintillation decay time, enabling a faster response to radiation events. Combined with NaI (Tl) crystals, this method can improve detection speed while maintaining high sensitivity. Different detectors respond differently to different types of background noise. Their combined use can better identify and eliminate interference signals from other sources, while simultaneously acquiring information on multiple parameters, improving the accuracy of radiation detection.

[0023] In addition, the present invention also provides a metal protective net in the underwater array radiation detector to protect the NaI (Tl) crystal detector and the CeBr3 crystal detector, thereby preventing the NaI (Tl) crystal detector and the CeBr3 crystal detector from breaking during underwater movement, thereby enabling the underwater array radiation detector of the present invention to perform mobile radiation detection and be applicable to radiation monitoring tasks in a variety of complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic structural diagram of an underwater array radiation detector provided by an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a curve showing the detection efficiency of gamma rays by NaI (Tl) crystals of different sizes provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a marine environment model detection efficiency curve provided by an embodiment of the present invention.

[0028] In the picture:

[0029] 1-first metal bracket; 2-NaI (Tl) crystal detector; 3-CeBr3 crystal detector; 4-second metal bracket; 5-triangle plate. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0031] The present invention proposes an underwater array radiation detector. Figure 1 : This is a schematic structural diagram of an underwater array radiation detector provided by an embodiment of the present invention. The underwater array radiation detector includes:

[0032] A first metal bracket 1 , at least one NaI (Tl) crystal detector 2 and at least one CeBr 3 crystal detector 3 ; the NaI crystal detector 2 and the CeBr 3 crystal detector 3 are fixed inside the first metal bracket 1 .

[0033] Furthermore, the underwater array radiation detector further includes a second metal bracket 4 and a triangular plate 5;

[0034] The second metal bracket 4 is fixed to the upper side of the triangular plate 5 and is used to securely connect the underwater array radiation detector to the monitoring platform;

[0035] The first metal bracket 1 is fixed to the lower side of the triangular plate 5 . The first metal bracket 1 is used to fix the NaI (Tl) crystal detector 2 and the CeBr 3 crystal detector 3 on the triangular plate 5 .

[0036] Among them, the monitoring platform can be but is not limited to large monitoring ships, various types of unmanned ships and other marine mobile platforms.

[0037] Specifically, NaI crystals are a commonly used gamma-ray detector material that is easy to prepare and has high detection efficiency, enabling low nuclide detection limits. Meanwhile, CeBr3 crystals have high energy resolution, enabling better discrimination of nuclides in seawater. Combining these two detection materials enables more accurate seawater radioactivity monitoring. By combining these two crystals, a wider energy range can be covered, improving detection sensitivity for different types of radiation.

[0038] Preferably, the number of NaI (Tl) crystal detectors 2 is 3, and the number of CeBr3 crystal detectors 3 is 1. Preferably, the NaI (Tl) crystal detector 2 is a cylinder with a diameter of 3 inches and a length of 6 inches, and the CeBr3 crystal detector 3 is a cylinder with a diameter of 2 inches and a length of 2 inches.

[0039] Specifically, through the early Monte Carlo simulation, 2-6 crystal arrays with different numbers were compared. Different numbers of crystal arrays will have different degrees of influence on the detection range, ray attenuation, etc. When the total volume of NaI (Tl) crystals is the same, the number and size of the crystals will affect the detection efficiency. Because large-volume crystals have their own shielding effect, they need to be split into small crystals to reduce the shielding effect. The more the number and the smaller the size, the greater the detection efficiency for the low-energy segment. It can be understood that its detection range becomes larger and more particles can be detected. However, its detection efficiency for the high-energy segment will decrease, because the product energy of high-energy particles in small crystals is small, so the detection efficiency will decrease instead. Specifically, Figure 2 This is a schematic diagram of the curve of the detection efficiency of NaI (Tl) crystals of different sizes for gamma rays provided by an embodiment of the present invention, see Figure 2 According to the simulation results, three large-volume NaI (Tl) crystals with a diameter of 3 inches and a length of 6 inches (i.e., Φ3×6 inches) have good detection efficiency in both high-energy and low-energy bands under the same volume and are easier to integrate. Therefore, the number and size of NaI (Tl) crystals are determined.

[0040] Since CeBr3 crystals are only used to identify nuclides in the environment, simulation tests show that only one probe with a diameter of 2 inches and a length of 2 inches (i.e. Φ2×2 inches) can meet the needs.

[0041] Furthermore, through actual calibration, it is known that the energy resolution of NaI(Tl) crystal is less than 7.5%@662 keV, the energy resolution of CeBr3 crystal is less than 4.5%@662 keV, and the detection limit of radionuclides is no higher than 0.01Bq / L( 137 Cs, 24h).

[0042] Among them, energy resolution is a property of the material itself. Through actual calibration, under the current size, the energy resolution of the gamma spectrometer of NaI#1 is 7%; the energy resolution of the gamma spectrometer of NaI#2 is 7.2%; the energy resolution of the gamma spectrometer of NaI#3 is 6.9%; the energy resolution of the gamma spectrometer of cerium bromide (CeBr3) is 4.44%. The smaller the energy resolution value, the better the detector performance, the easier it is to distinguish the types of radioactive nuclides in the gamma energy spectrum, and the higher the accuracy of the calculation of the activity concentration of the nuclides. The lower the detection limit of radioactive nuclides, the higher the accuracy and sensitivity of the detection system. Through preliminary comparative research on existing seawater radioactivity monitoring systems, the detection limit of underwater detectors currently in use is about 0.02Bq / L ( 137 Cs, 24h), while the structure of the present invention can achieve a detection limit of no more than 0.01Bq / L ( 137 Cs, 24h), which is at the international advanced level; the minimum detectable activity of different radionuclides at different times is shown in Table 1.

[0043] Table 1 Minimum detectable activity of different radionuclides at different times;

[0044]

[0045] Preferably, the NaI (Tl) crystal detectors 2 are arranged in a circumferential direction, and the distance between two adjacent NaI (Tl) crystal detectors 2 in the circumferential direction is 30 cm.

[0046] Specifically, the particle transport process is simulated by modeling the underwater array radiation detector, and the detector detection efficiency under the model and the passive efficiency calibration method of the seawater measurement boundary are calculated for calibration.

[0047] Furthermore, for a (Φ3×6)-inch NaI(Tl) crystal detector, the overall dimensions are a cylinder 67.5 cm high and 9.52 cm in diameter. The titanium alloy outer shell is 0.5 cm thick, the aluminum shell surrounding the crystal is 0.2 cm thick, the magnesium oxide reflective layer is 0.25 cm thick, and the crystal is covered with a 0.5 cm thick silica glass layer for connecting to the photomultiplier tube. The NaI(Tl) crystal detector's outer shell, except for the crystal, is filled with air. To ensure that each detector is farther from the seawater sphere boundary than its detection range, it is placed in a spherical seawater source with a radius of 150 cm for simulation.

[0048] Furthermore, through modeling, the full energy peak detection efficiency at different energies can be obtained. The full energy peak efficiency and gamma energy are fitted using the following formula:

[0049] ;

[0050] Where, It represents the total absorption peak detection efficiency of the NaI(Tl) crystal detector for γ-rays with energy E; represents the fitting constant; represents the energy corresponding to the gamma ray; k represents the highest order of the polynomial.

[0051] For example, k=6, the goodness of fit R 2 Reaching 0.9995, meeting the technical requirements, the ocean environment model detection efficiency curve is as follows Figure 3 As shown, the efficiency curve formula is as follows:

[0052] .

[0053] The detection efficiencies of the three NaI (Tl) crystal detectors are superimposed to obtain the comprehensive detection efficiency. In order to achieve the maximum detection efficiency while taking into account the influence of the self-shielding effect, the interval between two circumferentially adjacent NaI (Tl) crystal detectors 2 is set to 30 cm.

[0054] The obtained efficiency scale was verified by placing the NaI(Tl) crystal gamma spectrometer in the experimental environment. The large standard liquid source has a liquid level of 3m and a diameter of 2.5m. 137 Cs (0.85 Bq / L), 133 Ba (0.36Bq / L). The measurement was carried out 15 times, each measurement took 1 hour, and the efficiency calibration curve was used for calculation. 137 Cs and 133 Activity concentration of Ba, measurement results 137 The deviation between Cs and the standard value is less than 12%. 133 The deviation between Ba and the standard value is less than 5%, as shown in Table 2:

[0055] Table 2 Measured in the simulation environment 137 Cs, 133 Ba activity concentration.

[0056]

[0057] Preferably, the NaI (Tl) crystal detector 2 is arranged around the periphery of the CeBr 3 crystal detector 3 .

[0058] Specifically, the CeBr3 crystal detector 3 can be placed at any location within the range surrounding the NaI (Tl) crystal detector 2. Since the NaI (Tl) crystal detector 2 is a cylinder with a diameter of 3 inches and a length of 6 inches, and the CeBr3 crystal detector 3 is a cylinder with a diameter of 2 inches and a length of 2 inches, the CeBr3 crystal is shorter than the NaI (Tl) crystal. Therefore, placing the CeBr3 crystal detector 3 at any location will not block or affect the NaI (Tl) crystal. Placing the CeBr3 crystal detector 3 within the range surrounding the NaI (Tl) crystal detector 2, rather than outside of it, avoids adding to the overall volume of the underwater array radiation detector, which would increase the water-facing surface area during movement, thereby increasing resistance and impacting detection or movement.

[0059] Furthermore, the crystal detector includes: spectrometer electronics, GM counter tube, aluminum alloy bracket and detection crystal;

[0060] The spectrometer electronics, GM counter tube and detection crystal are fixed on the aluminum alloy bracket in sequence;

[0061] The detection crystal is NaI (Tl) crystal or CeBr3 crystal.

[0062] Specifically, spectrometer electronics amplify the weak electrical signals generated by the detector to a measurable level, filter and shape the amplified signal to remove noise, determine the energy of the incident radiation by analyzing the signal amplitude, record and store the signal information, and classify the signals by energy to form an energy spectrum. A GM counter tube (Geiger-Müller Counter Tube) is used to detect charged particles (such as beta particles) or high-energy gamma rays. When radiation enters the GM counter tube, it ionizes within the tube, generating an electrical pulse. Each pulse represents a detected radiation event, allowing the GM counter tube to count radiation events. An aluminum alloy bracket provides mechanical support, stabilizes the position of the detector components, and protects the detector from external physical damage. Aluminum alloy has good thermal conductivity, which helps dissipate heat and maintain the detector's operating temperature within a suitable range. In some designs, the aluminum alloy bracket may also provide a shielding effect, reducing background noise. Detection crystals are used when gamma rays or X-rays enter the crystal, generating electron-hole pairs inside the crystal. The generated electron-hole pairs cause the crystal to emit light (scintillation), a phenomenon known as the scintillation effect. The light signal is then detected by a photomultiplier tube or other light sensor and converted into an electrical signal.

[0063] Preferably, the spectrometer electronics, GM counter tube and detection crystal are fixed on the aluminum alloy bracket from top to bottom. The spectrometer electronics are placed at the top for communication and power supply, and the detection crystal is placed at the bottom to avoid obstruction that may reduce detection efficiency and detection effect.

[0064] Preferably, the underwater array radiation detector further includes a metal protective net (not shown in the figure), which is arranged outside the NaI (Tl) crystal detector 2 and the CeBr3 crystal detector 3 to protect the NaI (Tl) crystal detector 2 and the CeBr3 crystal detector 3.

[0065] Specifically, a metal protective net is provided on the outside of the NaI (Tl) crystal detector 2 and the CeBr3 crystal detector 3 to prevent marine organisms, floating objects or other hard objects from directly hitting or scratching the detectors, causing damage to the fragile crystal parts; the metal protective net increases the structural strength of the entire detector device, making it more sturdy and durable; thereby, the underwater array radiation detector of the present invention can be suitable for mobile radiation detection.

[0066] In addition, the metal protective net can also play a certain electromagnetic shielding role, reducing the impact of external electromagnetic interference on the electronic equipment inside the detector.

[0067] The present invention combines NaI (Tl) crystal detectors and CeBr3 crystal detectors to form an underwater array radiation detector. It combines the advantages of high detection efficiency of NaI (Tl) crystal detectors and good energy resolution of CeBr3 crystal detectors, and designs parameters such as the number, size, spacing, and arrangement of NaI (Tl) crystal detectors and CeBr3 crystal detectors. This can cover a wider energy range, improve the detection sensitivity to different types of radiation, and enhance the detection efficiency and energy resolution of the entire system. Mobile radiation detection also requires high detection efficiency to meet this requirement.

[0068] By combining multiple detectors to work simultaneously, the present invention can provide data redundancy. Even if a detector fails, the other detectors can continue to operate, ensuring data continuity and reliability. CeBr3 crystals have a relatively fast scintillation decay time, enabling a faster response to radiation events. Combined with NaI (Tl) crystals, this method can improve detection speed while maintaining high sensitivity. Different detectors respond differently to different types of background noise. Their combined use can better identify and eliminate interference signals from other sources, while simultaneously acquiring information on multiple parameters, improving the accuracy of radiation detection.

[0069] In addition, the present invention also provides a metal protective net in the underwater array radiation detector to protect the NaI (Tl) crystal detector and the CeBr3 crystal detector, thereby preventing the NaI (Tl) crystal detector and the CeBr3 crystal detector from breaking during underwater movement, thereby enabling the underwater array radiation detector of the present invention to perform mobile radiation detection and be applicable to radiation monitoring tasks in a variety of complex environments.

[0070] It should be noted that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the scope of this application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular and may also include the plural. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, the elements defined by the sentence "comprise a..." do not exclude the presence of other identical elements in the process, method or device comprising the elements.

[0071] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with 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. An underwater array radiation detector, characterized in that: include: A first metal support (1), at least one NaI(Tl) crystal detector (2) and at least one CeBr3 crystal detector (3); The NaI crystal detector (2) and the CeBr3 crystal detector (3) are fixed inside the first metal bracket (1); The number of the NaI(Tl) crystal detectors (2) is 3, and the number of the CeBr3 crystal detector (3) is 1; The NaI (Tl) crystal detector (2) is a cylinder with a diameter of 3 inches and a length of 6 inches, and the CeBr3 crystal detector (3) is a cylinder with a diameter of 2 inches and a length of 2 inches; The NaI (Tl) crystal detectors (2) are arranged in a circumferential direction, and the distance between two adjacent NaI (Tl) crystal detectors (2) in the circumferential direction is 30 cm; The NaI (Tl) crystal detector (2) is arranged around the periphery of the CeBr3 crystal detector (3).

2. The underwater array radiation detector according to claim 1, characterized in that: The NaI (Tl) crystal detector (2) and the CeBr3 crystal detector (3) both include: spectrometer electronics, a GM counter tube, an aluminum alloy bracket and a detection crystal; The spectrometer electronics, the GM counter tube and the detection crystal are fixed on the aluminum alloy bracket in sequence; The detection crystal is a NaI (Tl) crystal or a CeBr3 crystal.

3. The underwater array radiation detector according to claim 1, characterized in that: It also includes a metal protection net, which is arranged outside the NaI (Tl) crystal detector (2) and the CeBr3 crystal detector (3) and is used to protect the NaI (Tl) crystal detector (2) and the CeBr3 crystal detector (3).

4. The underwater array radiation detector according to claim 1, characterized in that: It also includes a second metal bracket (4) and a triangular plate (5); The second metal bracket (4) is fixed to the upper side of the triangular plate (5) and is used to fixedly connect the underwater array radiation detector to the monitoring platform; The first metal bracket (1) is fixed to the lower side of the triangular plate (5), and the first metal bracket (1) is used to fix the NaI (Tl) crystal detector (2) and the CeBr3 crystal detector (3) on the triangular plate (5).

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