Elemental analysis device based on high-yield DD neutron generator

Abstract

The invention discloses an element analysis device based on a high-yield DD neutron generator. The device is composed of a neutron source item system, a neutron shielding collimation wall, a detector shielding protection system, a detected sample system, a signal acquisition system and a data analysis system. A neutron beam is generated through (D, D) nuclear reaction and irradiates a sample after passing through a neutron moderation layer and a shielding collimation wall, so that the sample generates instant characteristic gamma rays. A shielding protection system with unique design effectively reduces background gamma ray interference and electromagnetic interference, and ensures that the detector accurately collects sample signals. By matching with an advanced signal acquisition and analysis system, the element components and content of the sample can be analyzed at high precision. In addition, the device can be combined with a neutron imaging system to obtain sample structure information. The method has great application potential in the fields of industrial production, scientific research and detection and the like, and can meet the requirements of high-precision element analysis on small-size samples.

Description

Technical Field

[0001] The present invention belongs to the technical field related to elemental analysis and detection, and particularly relates to an elemental analysis device based on a high-yield DD neutron generator. Background Art

[0002] Prompt gamma neutron activation analysis (PGNAA) technology has advantages such as high sensitivity, multi-element analysis, real-time measurement, and non-destructiveness in the field of elemental analysis inside substances, and has been widely applied in many fields such as coal, cement production, mineral exploration, and cultural relics detection. Its principle is that a neutron source generates neutron rays to bombard the sample to be detected, causing the atomic nuclei of different elements in the sample to be excited to the excited state and accompanied by the generation of gamma rays. By collecting the gamma signals of the sample through a gamma detector for energy and intensity analysis, the elemental composition and content of the sample can be obtained.

[0003] Currently, in the PGNAA devices used for on-line analysis in industrial production, the yield of the DD neutron source is at most about 10 6 n / s and the volume of the sample to be measured is very large. For example, in a cement production line, high-quality cement is obtained by detecting the elemental content of a large amount of raw materials (such as limestone, clay, etc.) and automatically controlling the raw material ratio. For small-volume samples, generally a nuclear reactor neutron source is commonly used for measurement. This nuclear reactor neutron activation analysis (ReNAA) is very difficult to apply in industrial production due to the limitations of the reactor itself. However, in recent years, with the continuous maturity of the (D,D) nuclear fusion reaction technology, the highest yield of the DD neutron source developed by relevant scientific research institutions has been increased to 10 10 n / s, greatly improving the accuracy of analyzing the composition of small-volume samples in the industrial field.

[0004] However, in the face of such a high-yield neutron source, when measuring the sample, there will be serious interference from the background signal (gamma signal not generated by the sample) and electromagnetic interference, affecting the accuracy of analyzing the elemental content of the sample. Therefore, it is urgent to design a new type of elemental analysis device based on a high-yield DD neutron source, focusing on solving the problems of reducing the interference of the background gamma signal on the gamma signal of the sample to be detected and shielding and protecting against electromagnetic interference. Summary of the Invention

[0005] The purpose of the present invention is to provide an elemental analysis device based on a high-yield DD neutron generator to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] An element analysis device based on a high-yield DD neutron generator mainly includes a DD neutron source system, a neutron shielding and collimating wall, a detector shielding and protection system, a sample system to be inspected, a signal acquisition system, and a data analysis system. It is characterized in that: the DD neutron source system generates 2.45 MeV neutrons through (D, D) nuclear reactions, and the yield reaches ~10 10 n / s magnitude; an anisotropic neutron beam is generated at the target point; the DD neutron source system and the neutron shielding and collimating wall are arranged in a cube closed space made of boron polyethylene; the detector shielding and protection system consists of a gamma shielding layer and a neutron absorption layer; the sample system to be inspected is on the same horizontal line as the collimation hole of the shielding and collimating wall; the signal acquisition system includes detector signal output, a multi-channel pulse gamma signal analysis spectrometer, and a computer control part.

[0008] Preferably, for the neutron beam generated by the DD neutron source system from the target point, after passing through the neutron moderation layer and the collimation hole of the neutron shielding wall, the proportion of fast neutron flux is extremely high, and there are serious electromagnetic interference problems, which inhibit the acquisition of prompt gamma signals generated by the detector system for the sample to be inspected.

[0009] Preferably, the neutron shielding and collimating wall uses a high-density polyethylene material with a thickness of 3 cm - 5 cm as the neutron moderation layer to reduce the fast neutron flux entering the detector; the neutron shielding and collimating wall is a cuboid structure with a length of 54.5 cm, a height of 156 cm, and a thickness of 3 cm. At the horizontal line with the target point, a frustum-shaped collimation hole with a radius of 3 - 4 cm is designed.

[0010] Preferably, the gamma shielding layer of the detector shielding and protection system wraps the detector on all sides with 2 cm thick heavy metal lead; the neutron absorption layer is made of 1 cm thick lithium fluoride material and placed outside the gamma shielding layer; the gamma detector selects a 3×3 inch NaI detector, a lanthanum bromide detector, or a bismuth germanate detector; the neutron shielding layer of the detector shielding and protection system is a cuboid structure of 5 - 6 cm polyethylene material, the gamma shielding layer is a cuboid structure of 4 cm heavy metal lead wrapping the gamma detector on all sides, and a 1 - 2 mm cadmium sheet or 1 cm lithium fluoride is added between the neutron shielding layer and the gamma shielding layer as the neutron absorption layer.

[0011] Preferably, the sample system to be inspected is at a 90° angle to the detector end face, and the central distance is 4 - 10 cm; a collimation hole with a diameter of 3 - 4 cm is designed between the gamma detector and the sample using heavy metal lead, and the collimation hole is covered with a cadmium sheet, 1 - 2 cm boron carbide, or lithium fluoride material as the neutron absorption layer.

[0012] Preferably, the multi-channel pulse gamma spectrometer of the signal acquisition system is of model V1725sc or DP5730, which is connected to a computer through a data cable. With the help of the computer control software COMPASS, the energy spectrum can be obtained in the data analysis system, and single-peak analysis and full-spectrum analysis can also be carried out.

[0013] The present invention further provides a method for an element analysis device and a neutron radiography device to measure a sample simultaneously or separately under the same neutron source system. The specific steps are as follows:

[0014] Preparation work: Place the neutron shielding collimator wall of the element analysis device vertically below on the guide rail. The detector shielding system and the sample to be inspected are placed on the aluminum frame, and the aluminum frame is placed vertically on the guide rail. At the same time, place the moderating collimator wall of the neutron radiography device vertically on another guide rail, and the three guide rails are independently driven by motors.

[0015] Separate sample element analysis: Drive the guide rail by the motor. The guide rail moves the neutron shielding collimator wall, the detector shielding system and the sample to be inspected of the element analysis device to the neutron source system, so that the neutron shielding collimator wall is close to the neutron moderation layer of the neutron source system. Adjust the relative positions of the detector shielding system and the sample to be inspected and start the measurement.

[0016] Simultaneously measure the sample structure and element content: First, fix the CCD camera at a position 50 cm above the surface of the neutron moderation layer of the neutron source system facing the area to be measured. After the guide rail and the guide rail are restored to the initial position, drive the guide rail 3 by the motor to move the neutron radiography moderating collimator wall to the neutron source system, and then drive the guide rail by the motor to move the aluminum frame (detector shielding system and sample system to be inspected) to the neutron radiography moderating collimator wall. At this time, the CCD camera, the sample to be inspected, and the collimation hole are on the same horizontal line, while the gamma detector and the sample to be inspected are in the vertical direction and form a 90° angle with the collimation hole.

[0017] Compared with the prior art, the present invention provides an element analysis device based on a high-yield DD neutron generator, which has the following beneficial effects:

[0018] With the carefully designed neutron shielding collimator wall and detector shielding and protection system, the present invention greatly reduces the background gamma ray interference and electromagnetic interference. The neutron shielding collimator wall uses high-density polyethylene material with a specific thickness as the neutron moderation layer, effectively reducing the fast neutron flux entering the detector; the precisely designed inverted cone collimation holes inside ensure that the thermal neutron beam irradiates the sample precisely, significantly reducing the interference of stray neutrons. The gamma shielding layer of the detector shielding and protection system uses the high attenuation characteristics of heavy metal lead for gamma rays to strongly block the gamma rays generated by the environment and the device itself; the neutron absorption layer intercepts the thermal neutrons coming from the side and scattered by reasonably selecting materials with strong thermal neutron absorption ability such as cadmium sheets and lithium fluoride. These innovative designs effectively reduce the interference signals and ensure that the detector can efficiently collect the effective signals of the sample.

[0019] With the help of a high-yield DD neutron generator, this device can generate a neutron beam with stable flux and high intensity, providing sufficient excitation energy for the elemental analysis of samples. Combined with an advanced signal acquisition system and data analysis system, the CAEN digital multi-channel analyzer and the professional COMPASS software can accurately analyze the characteristic gamma signals of the samples collected by the detector, accurately identify the characteristic peaks of different elements, and then achieve high-precision analysis of the elemental composition and content of the samples. Compared with traditional elemental analysis devices, when analyzing small-volume samples, the present invention can effectively avoid detection errors caused by weak signals, greatly improving the accuracy and reliability of the analysis results, and meeting the requirements for high-precision elemental analysis in fields such as industrial production and scientific research detection.

[0020] The present invention has the unique advantage of being used in combination with a neutron imaging system. Through the cleverly designed rail drive system, the positions of each device can be conveniently adjusted to achieve the function of separately performing elemental analysis of samples or simultaneously obtaining the elemental content and structural information of samples. This feature makes the device have stronger adaptability and comprehensiveness in practical applications. For example, in cultural relics detection, it can not only analyze the material composition of cultural relics, but also synchronously obtain their internal structural information, providing more comprehensive data support for cultural relics protection and research; in materials science research, it can help researchers deeply understand the relationship between the elemental distribution and the microscopic structure of materials, promoting the development and innovation of materials science.

[0021] The neutron source term system is equipped with dedicated cooling and power supply devices. The cooling system adopts high-efficiency liquid cooling technology, which can timely remove the heat generated by the neutron generator, ensure the stable operation of the device within an appropriate temperature range, and avoid performance degradation or component damage caused by overheating. The power supply device accurately provides stable high-voltage direct current according to the power demand of the neutron generator, strictly controls the voltage fluctuation, and effectively guarantees the continuity and stability of the neutron generation process. In addition, during the construction and installation of the device, each component is installed using a high-precision positioning tooling, and flexible sealing materials are added at key joint parts to ensure the sealing and stability of the device, effectively reducing the impact on the device operation caused by problems such as component loosening or neutron leakage, and providing a reliable guarantee for long-term stable elemental analysis work. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the elemental analysis device of the DD neutron generator provided by the present invention.

[0023] Figure 2 It is a measurement diagram of different scenarios of neutron radiography and elemental analysis provided by the present invention.

[0024] In the figure: 1. DD neutron source term system; 2. Neutron shielding and collimating wall; 3. Neutron shielding and collimating wall; 4. Neutron shielding and collimating wall; 5. Neutron shielding and collimating wall; 6. Neutron shielding and collimating wall; 7. Neutron shielding and collimating wall; 8. (D,D) neutron target point; 9. Neutron moderation layer. Detailed Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] The present invention provides as Figure 1-2 shown

[0027] An elemental analysis device based on a high-yield DD neutron generator mainly includes a DD neutron source term system 1, a neutron shielding and collimating wall 2, a detector shielding and protection system 3, a sample to be inspected system 4, a signal acquisition system 5, and a data analysis system 6. The DD neutron source term system generates 2.45 MeV neutrons through (D,D) nuclear reactions, and the yield reaches ~10 10n / s order of magnitude; anisotropic neutron beam is generated at the target point; the DD neutron source system and the neutron shielding collimation wall 2 are arranged in a cubic closed space made of boron polyethylene; the detector shielding protection system 3 is composed of a gamma shielding layer and a neutron absorption layer; the sample system 4 is on the same horizontal line with the collimation hole of the shielding collimation wall; the signal acquisition system 5 covers the detector signal output, the multi-channel pulse gamma signal analysis spectrometer and the computer control part.

[0028] Neutron source term system

[0029] The neutron source uses a DD neutron generator with advanced technology. Its core component is the (D,D) neutron target 8, which is carefully placed in the vacuum environment inside the neutron moderator 9. The neutron moderator 9 is made of polyethylene and is designed as an internal hollow isosceles trapezoidal structure with an upper bottom length of precisely 10 cm, a lower bottom length of 18 cm, a waist length of about 27 cm, and a thickness (height) of 20 cm. The distance between the target and the center of the upper bottom surface of the neutron moderator 9 is strictly controlled to be 6 cm. This setting can ensure that the target produces ~10 10 The n / s anisotropic 2.45MeV neutron beam reaches an ideal thermal neutron flux density distribution when passing through the neutron moderator 9. According to experimental measurements, the thermal neutron flux density of the neutron moderator 9 is about 10 6 The outermost layer is wrapped with a boron-containing polyethylene shield 1 to block unnecessary neutron leakage, ensure the safety of the surrounding environment of the device, and prevent external interference from affecting the neutron beam.

[0030] In order to ensure the stable operation of the neutron source system, a dedicated cooling and power supply device is designed. The cooling system adopts high-efficiency liquid cooling technology. The coolant circulates through the key heating parts of the neutron generator to take away the heat in time, ensuring that the operating temperature of the device is maintained in an appropriate range to avoid performance degradation or component damage due to overheating. The power supply device accurately provides stable high-voltage direct current according to the power requirements of the neutron generator, and its voltage fluctuation is controlled within a very small range to ensure the continuity and stability of the neutron generation process.

[0031] Neutron shielding collimation wall

[0032] The neutron shielding collimation wall 1 is a rectangular parallelepiped structure with a length of 54.5 cm, a height of 156 cm, and a thickness of 3 cm. The material is selected as polyethylene to give full play to its neutron slowing down and shielding characteristics. At the horizontal line corresponding to the target point, an inverted cone collimation hole with a radius of 3-4 cm is carefully processed. The shape and size of the collimation hole have been simulated and optimized many times to ensure that the thermal neutron beam can irradiate the sample to be tested at a precise angle and flux, minimize the interference of stray neutrons on the subsequent detection process, make the sample evenly irradiated, and lay the foundation for accurately obtaining the characteristic gamma rays of the sample.

[0033] The neutron shielding collimation wall 1 is closely fitted to the neutron moderator beam exit surface of the DD neutron source system. High-precision positioning tooling is used during the installation process to ensure that the gap between the two is controlled at the sub-millimeter level to prevent neutron leakage. At the same time, flexible sealing materials are added to the joint between the two to further enhance the sealing and ensure the stability and controllability of the neutron beam path.

[0034] Detector shielding protection system

[0035] The gamma shielding layer 4 is a circular rectangular parallelepiped structure with a height of 40 cm, a length of 14 cm, and a thickness of 5 cm. The heavy metal lead is used as the material. With the high attenuation ability of lead to gamma rays, it effectively blocks the gamma rays generated by the surrounding environment and the device itself from entering the detector, reducing the background gamma signal interference. During the manufacturing process, the lead material is finely processed to ensure the sealing and integrity of the shielding layer to avoid gaps that cause gamma ray leakage.

[0036] The neutron shielding layer adopts a 5-6cm polyethylene rectangular structure and is arranged along the neutron beam direction close to the gamma shielding layer 4. Two polyethylene rectangular blocks with a length of 14cm, a height of 40cm and a thickness of 2-4cm are placed on both sides of the gamma shielding layer 4 to work together to further slow down the fast neutrons that may enter the detector and reduce the impact of fast neutrons on the detector performance.

[0037] The neutron absorption layer 5 is composed of two parts. A layer of about 2mm cadmium sheet or 1-2cm lithium fluoride is laid near the side of the neutron shielding collimation wall 1. These materials have a strong absorption capacity for thermal neutrons and can accurately intercept thermal neutrons entering the detector from the side to prevent them from interfering with the normal operation of the detector. A piece of lithium fluoride material is precisely placed between the sample to be tested and the end face of the detector, covering the gamma shielding layer 4, specifically absorbing thermal neutrons scattered from the collimation hole, ensuring that the detector only receives valid gamma signals from the sample.

[0038] The gamma detector 6 uses any one of the NaI (Ti) detector, LaBr3 (Ce) detector or BGO detector with a crystal size of 3×3 inches (7.62cm), and is flexibly selected according to different detection requirements and environmental conditions. When the detector is installed, the high-precision mechanical structure is closely matched with the gamma shielding layer 4 to ensure that the detector probe and the collimation hole are in a precise 90° vertical relationship, ensuring efficient collection of sample gamma rays.

[0039] Test sample system

[0040] The core component of the sample system to be tested is sample 3, which is precisely placed at the position directly opposite the collimation hole of the neutron shielding collimation wall, and it is ensured that the collimation hole, sample 3, and gamma detector are perfectly vertically arranged. The sample stage is designed as an adjustable structure, capable of precisely adjusting the position of the sample in three-dimensional space to meet the detection requirements of samples with different sizes and shapes. During the sample placement process, a special sample fixing fixture is used to ensure that the sample remains stable during the detection process and will not be displaced due to device vibration or other factors, affecting the accuracy of the detection results.

[0041] Considering the neutron scattering problem between the sample and the detector, a collimation hole with a diameter of 3 - 4 cm is designed between the gamma detector and the sample using heavy metal lead. This collimation hole can not only limit the receiving angle of gamma rays and improve the accuracy of signal acquisition, but also serve as a preliminary neutron shielding structure. Further, cadmium sheets, 1 - 2 cm of boron carbide or lithium fluoride materials are used to cover the collimation hole to enhance its neutron absorption ability and minimize the interference of neutron scattering on the detection results to the greatest extent.

[0042] Signal acquisition system and data analysis system

[0043] The signal acquisition system selects the V1725sc multi-channel pulse amplitude analyzer or DT5730 multi-channel pulse amplitude analyzer produced by CAEN. Both of these analyzers have the ability to collect and analyze pulse signals with high precision and high sensitivity. The output signal of the detector is tightly connected to the selected analyzer through high-quality and anti-interference signal lines to ensure no loss and no distortion during the signal transmission process. The analyzer realizes stable and high-speed data transmission with the computer through the USB data cable, providing a solid data foundation for subsequent data analysis.

[0044] The data analysis system runs relying on a computer and installs a specially customized COMPASS software. This software has a friendly interface and powerful functions. It can receive data from the signal acquisition system in real time and quickly perform energy spectrum processing. Operators can conveniently perform single-peak analysis through this software to accurately identify the gamma-ray characteristic peaks generated by specific elements, thereby determining the presence and content information of the elements in the sample; or perform full-spectrum analysis to comprehensively interpret the entire energy spectrum and obtain the multi-element information of the sample to comprehensively understand the element composition of the sample.

[0045] Workflow

[0046] Sample Preparation and Device Positioning: Carefully place the sample to be detected on the sample stage and use the adjustment function of the sample stage to place it in the initial detection position. Subsequently, drive and control Guide Rail 1 and Guide Rail 3 through the motor, and move the neutron shielding collimation wall 2 for elemental analysis, the sample 3 to be detected, the neutron moderation layer 7 of the detector shielding protection system, the neutron absorption layer 5, and the gamma shielding layer 4 to the surface of the neutron moderation layer 9 of the neutron source term system along a preset high-precision path. During this process, the motor drive system precisely controls the moving speed and position of each component according to the pre-set program, ensuring the accurate relative position between each component, and avoiding collisions or displacement deviations.

[0047] Collection of Characteristic Gamma Signals of the Sample: Start the neutron source, and a stable neutron beam is emitted from the target point 8. After the neutron beam is finely moderated by the neutron moderation layer 9 and precisely collimated by the neutron shielding collimation wall 1 in sequence, it irradiates the sample uniformly. The characteristic gamma signals generated by the stimulated sample are efficiently collected by the gamma detector 6. The gamma detector 6 transmits the received signals to the CAEN digital multi-channel analyzer V1725sc in real time through the signal line. The analyzer immediately conducts in-depth analysis on the pulse signals, extracts key characteristic parameters of the signals, such as pulse amplitude, frequency, etc., and quickly transmits the analysis results to the computer through the USB data cable.

[0048] Energy Spectrum Processing and Elemental Analysis: On the computer side, the COMPASS software receives the data from the analyzer in real time and quickly plots the energy spectrum diagram. The operator uses the rich tools of the software to perform single-peak analysis or full-spectrum analysis on the energy spectrum, and accurately identifies the elements and their contents contained in the sample based on the characteristic energies and intensities of gamma rays of different elements. During this process, the intelligent algorithm built into the software can automatically remove the background noise and interference signals, further improving the accuracy of the analysis results.

[0049] Optionally, it works in cooperation with the neutron radiography device: If it is necessary to obtain the structural information and elemental content of the sample simultaneously, first firmly fix the CCD camera at a position 50 cm on the surface of the neutron moderation layer directly facing the neutron source system in the area to be measured, ensuring that the camera can clearly capture the structural image of the sample. After the guide rail 1 is restored to the initial position, drive the guide rail 3 by the motor to move the neutron radiography moderation collimation wall to the surface of the neutron moderation layer 9 of the neutron source term system, and then drive the guide rail 2 by the motor to move the aluminum frame (detector shielding system and the sample to be inspected system) to the neutron radiography moderation collimation wall. At this time, the CCD camera, the sample to be inspected, and the collimation hole are on the same horizontal line, while the gamma detector and the sample to be inspected are in the vertical direction and form a 90° angle with the collimation hole. Start the neutron source, and the neutron beam irradiates the sample simultaneously. The gamma detector collects the energy and intensity of the characteristic gamma rays of the sample elements, and the neutron CCD camera collects the structural information of the sample. The data collected by both are transmitted to the corresponding analysis systems respectively, and through the backend data processing, the elemental composition detection and structural information detection are realized simultaneously. During the cooperation process, the motor drive, signal transmission, and data processing between the devices are all precisely synchronized to ensure the consistency of the sample elemental information and structural information in terms of time and space.

[0050] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An element analysis device based on a high-yield DD neutron generator, characterized in that: The invention mainly comprises a DD neutron source system (1), a neutron shielding collimation wall (2), a detector shielding protection system (3), a sample system (4), a signal acquisition system (5) and a data analysis system (6), wherein the DD neutron source system generates 2.45 MeV neutrons through a (D, D) nuclear reaction, and the yield reaches 10 10 n / s level; anisotropic neutron beam is generated at the target point; the DD neutron source system and the neutron shielding collimation wall (2) are arranged in a cubic closed space made of boron polyethylene; the detector shielding protection system (3) is composed of a gamma shielding layer and a neutron absorption layer; the sample system (4) is on the same horizontal line as the collimation hole of the shielding collimation wall; the signal acquisition system (5) covers the detector signal output, the multi-channel pulse gamma signal analysis spectrometer and the computer control part.

2. The element analysis device based on a high-yield DD neutron generator according to claim 1, characterized in that: The neutron beam generated by the DD neutron source system (1) from the target point has a very high fast neutron flux after passing through the neutron moderation layer and the collimation hole of the neutron shielding wall, and is accompanied by a serious electromagnetic interference problem, which inhibits the detector system from collecting the prompt gamma signal generated by the sample under inspection.

3. The element analysis device based on a high-yield DD neutron generator according to claim 1, characterized in that: The neutron shielding collimation wall (2) uses a high-density polyethylene material with a thickness of 3 cm-5 cm as a neutron moderation layer, which is used to reduce the fast neutron flux entering the detector; the neutron shielding collimation wall is a rectangular parallelepiped structure with a length of 54.5 cm, a height of 156 cm and a thickness of 3 cm, and is designed with an inverted cone collimation hole with a radius of 3-4 cm at the horizontal line with the target point.

4. The element analysis device based on a high-yield DD neutron generator according to claim 1, characterized in that: The gamma shielding layer of the detector shielding protection system (3) is made of 2 cm thick heavy metal lead wrapped around the detector; the neutron absorption layer is made of 1 cm thick lithium fluoride material and is placed outside the gamma shielding layer; the gamma detector uses a 3×3 inch NaI detector, a lanthanum bromide detector or a bismuth germanate detector; the neutron shielding layer of the detector shielding protection system is a 5-6 cm rectangular parallelepiped structure of polyethylene material, the gamma shielding layer is a 4 cm heavy metal lead rectangular parallelepiped structure wrapped around the gamma detector, and a 1-2 mm cadmium sheet or 1 cm lithium fluoride is added between the neutron shielding layer and the gamma shielding layer as a neutron absorption layer.

5. The element analysis device based on a high-yield DD neutron generator according to claim 1, characterized in that: The sample system (4) to be tested is 90 degrees to the end face of the detector, and the center distance is 4-10 cm; a collimating hole with a diameter of 3-4 cm is designed using heavy metal lead between the gamma detector and the sample, and the collimating hole is covered with a cadmium sheet and 1-2 cm boron carbide or lithium fluoride material as a neutron absorption layer.

6. The element analysis device based on a high-yield DD neutron generator according to claim 1, characterized in that: The multi-channel pulse gamma spectrometer of the signal acquisition system (5) is of model V1725sc or DP5730, which is connected to a computer via a data cable, and uses the computer control terminal software COMPASS to enter the data analysis system to obtain the energy spectrum, and can also perform single peak analysis and full spectrum analysis.

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