阅读说明：本技术 一种基于氘氘中子发生器的热中子分析探雷装置 (Thermal neutron analysis mine detection device based on deuterium and deuterium neutron generator ) 是由 郭小峰 储诚胜 许业文 张迎增 曾军 向清沛 袁志文 郝樊华 向永春 朱晨 杨圣 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种基于氘氘中子发生器的热中子分析探雷装置。该装置包括低能中子吸收体、铅屏蔽体、伽马探测器、源强监测探测器、中子反射体、中子发生器和中子慢化体。低能中子吸收体、铅屏蔽体和伽马探测器依次按照从外到内的顺序进行包裹,共同构成一个下端靠近且上端远离中子发生器的探测单元；中子发生器位于装置的中心,中子反射体包裹在中子发生器的侧面,中子慢化体紧贴在中子发生器的正下方,四个探测单元均匀且对称地分布在中子发生器的侧面的四个方向；源强监测探测器从顶上嵌入到反射体的内部。该装置采用氘氘中子发生器作为中子源,采用LaBr<Sub>3</Sub>(Ce)探测器作为伽马探测器,通过氮元素含量异常检测可实现对地雷目标的快速探测和准确识别。(The invention discloses a thermal neutron analysis mine detection device based on a deuterium and deuterium neutron generator. The device comprises a low-energy neutron absorber, a lead shield, a gamma detector, a source intensity monitoring detector, a neutron reflector, a neutron generator and a neutron moderator. The low-energy neutron absorber, the lead shield and the gamma detector are sequentially wrapped from outside to inside to form a detection unit with the lower end close to the neutron generator and the upper end far away from the neutron generator; the neutron generator is positioned in the center of the device, the neutron reflector wraps the side surface of the neutron generator, the neutron moderating body is tightly attached to the position right below the neutron generator, and the four detection units are uniformly and symmetrically distributed in four directions of the side surface of the neutron generator; the source intensity monitoring detector is embedded into the reflector from the top. The device adopts deuterium and deuterium neutron generator as neutron source and adopts LaBr 3 (Ce) detector as gamma detector, by nitrogen content anomalyThe detection can realize the rapid detection and accurate identification of the mine target.)

1. A thermal neutron analysis mine detection device based on deuterium and deuterium neutron generator is characterized in that: the mine detection device comprises a low-energy neutron absorber (1), a lead shield (2), a gamma detector (3), a source intensity monitoring detector (5), a neutron reflector (6), a neutron generator (7) and a neutron moderator (9);

The neutron generator (7) is a cylinder and is positioned in the center of the whole device, a neutron generator control cabinet (11) is connected with the neutron generator (7) through a cable, the neutron generator control cabinet (11) provides accelerating high voltage and ion source voltage for the neutron generator (7), the neutron generator control cabinet (11) is connected with a PC terminal (14) through a network cable, and control software of the PC terminal (14) is used for carrying out parameter regulation and control on the neutron generator control cabinet (11); the neutron moderating body (9) is in a disc shape and is tightly attached to the right lower part of the neutron generator (7); the neutron reflector (6) is a hollow cylinder and is tightly wrapped on the outer sides of the neutron generator (7) and the neutron moderator (9); the source intensity monitoring detector (5) is a cylinder and is inserted into the neutron reflector (6) from top to bottom, the power supply module (4) of the source intensity monitoring detector provides high voltage for the source intensity monitoring detector (5), and a pulse signal measured by the source intensity monitoring detector (5) is converted into a digital signal after being analyzed by the source intensity monitoring detector signal acquisition and processing module (10) and is transmitted to the PC terminal (14);

The lead shielding body (2) is a hollow cylinder with a closed bottom surface, a cavity of the hollow cylinder deviates from the neutron generator (7), namely the thickness of the lead shielding body (2) close to one side of the neutron generator (7) is larger than that of the lead shielding body (2) far away from one side of the neutron generator (7); the gamma detector (3) is placed in a cavity of the lead shielding body (2), the gamma detector power supply module (13) provides high voltage and low voltage for the gamma detector (3), and pulse signals measured by the gamma detector (3) are converted into digital signals after linear amplification and pulse amplitude analysis of the gamma detector signal acquisition and processing module (12) and are transmitted to the PC terminal (14); the low-energy neutron absorber (1) is wrapped on the side surface and the bottom surface of the lead shielding body (2);

the low-energy neutron absorber (1), the lead shielding body (2) and the gamma detector (3) form a detection unit, the detection unit inclines in the vertical direction, the inclination direction is that the lower end of the detection unit is close to the neutron generator (7), and the upper end of the detection unit is far away from the neutron generator (7); the mine detecting device comprises four detecting units which are uniformly and symmetrically distributed in four directions of the side surface of the neutron generator (7).

2. The thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator as claimed in claim 1, wherein the low energy neutron absorber (1) is made of cadmium, and the thickness of cadmium sheets on the side surface and the bottom surface of the low energy neutron absorber (1) is 1mm ~ 2 mm.

3. The thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator as claimed in claim 1, wherein the lead shield (2) is made of old lead, the thickness of the lead shield (2) close to the neutron generator (7) is 3 cm ~ 5cm, the thickness of the lead shield (2) far away from the neutron generator (7) is 1 cm ~ 2 cm, and the thickness of the bottom surface of the lead shield (2) is 3mm ~ 5 mm.

4. The deuterium neutron generator-based thermal neutron analysis mine detection device according to claim 1, wherein: the gamma detector (3) adopts LaBr₃(Ce) detectors, LaBr₃The diameter and height of the (Ce) crystal were both 7.62 cm.

5. The deuterium neutron generator-based thermal neutron analysis mine detection device according to claim 1, wherein: the source intensity monitoring detector (5) adopts³He is proportional to the count tube.

6. The deuterium neutron generator-based thermal neutron analysis mine detection device according to claim 1, wherein: the neutron generator (7) adopts a deuterium-deuterium neutron generator, and the average energy of emitted neutrons is 2.5 MeV.

7. The deuterium neutron generator-based thermal neutron analysis mine detection device according to claim 1, wherein: the neutron generator (7) adopts a single structure, namely, the sealed neutron tube, the inverter and the multiplier are fixedly packaged in the interior of the neutron generator (7) in an equipotential mode, and No. 45 transformer oil is used as an insulating, moderating and reflecting material.

8. The thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator as claimed in claim 1, wherein the neutron reflector (6) is made of high density polyethylene and has a lateral thickness of 5cm ~ 8 cm.

9. the thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator as claimed in claim 1, wherein the neutron moderating body (9) is made of high density polyethylene and has a height of 1 cm ~ 4 cm.

Technical Field

The invention belongs to the technical field of nuclear radiation detection, particularly relates to the technical field of thermal neutron analysis and gamma detection, and particularly relates to a thermal neutron analysis mine detection device based on a deuterium-deuterium neutron generator.

Background

The "thermal neutron analysis mine" is a mine using thermal neutrons as raw materialA new mine-exploring method for detecting explosive by probe features that thermal neutrons and mine explosive are used¹⁴Generation of N element (a)n，γ) Reaction, i.e.n(thermal)+¹⁴N→¹⁵N^* →¹⁵N+γ(10.83 MeV), the characteristic gamma ray intensity with the energy of 10.83 MeV generated by the method can be used for representing whether the tested object contains explosives or not and information such as explosive content. The thermal neutron analysis mine detection technology is characterized in that a target object is identified based on the content of nitrogen elements, and the thermal neutron analysis mine detection technology has the advantages of high reliability, low false alarm rate and easiness in implementation, and is particularly suitable for application scenes of vehicle-mounted mine detection.

Japan, italy and canada are leading around the world in the field of research on thermal neutron analysis mine technologies, and practical vehicle-mounted thermal neutron analysis mine systems have been developed. The mine detection system developed in Japan adopts a deuterium-deuterium neutron generator as a neutron source and adopts a combined structure of wrapping a NaI (Tl) detector outside a BGO detector as a gamma detector, so that the incident neutron intensity and the induced gamma ray measurement signal-to-noise ratio are improved; the mine detection systems developed in Italy and Canada all use radionuclides²⁵²Cf is used as a neutron source, and four NaI (Tl) detector arrays are used as gamma detectors, so that the melamine and the Tanke mine can be effectively detected. Although the conventional thermal neutron analysis mine detection system in international inspection can realize effective detection on certain specific mines, the problem of long detection time still exists. To solve this problem, on the one hand, the incident neutron intensity needs to be continuously increased, and on the other hand, a gamma detector with better performance needs to be selected.

The research of the thermal neutron analysis mine exploring technology in China also has a history of nearly ten years, and the research unit is mainly the nuclear physics and chemical research institute of the Chinese engineering physics institute and the liberation military 63983 army of Chinese people. The team of the applicant is dedicated to the research of neutron challenge mine detection technology for a long time, and develops a series of mine detection technologies and mine detection identification algorithms, including specific technologies such as thermal neutron analysis mine detection, pulse fast thermal neutron analysis mine detection and neutron backscattering mine detection, and the like, as well as a 3 sigma decision function, automatic searching of characteristic peak energy regions and a groundAnd specific algorithms such as simple positioning of the radar target, probability matrix source tracing imaging and the like. Meanwhile, with the development of the development technology of the domestic neutron generator, the deuterium neutron generator is feasible to be applied to the thermal neutron analysis mine detection. The deuterium-deuterium neutron generator specially developed for the thermal neutron analysis mine detection technology can obtain higher neutron yield and can meet the requirement of the thermal neutron analysis mine detection technology on neutron intensity. And, compared with the conventional one²⁵²The Cf isotope neutron source and the neutron emitting beam of the deuterium neutron generator can be adjusted and closed, and the radiation safety is higher.

Therefore, in order to accelerate the detection speed of the mine buried in the soil and reduce the radiation dose of operators, it is necessary to develop a thermal neutron analysis mine detection device based on a deuterium and deuterium neutron generator.

Disclosure of Invention

the invention aims to solve the technical problem of providing a thermal neutron analysis mine detection device based on a deuterium and deuterium neutron generator.

The invention discloses a thermal neutron analysis mine detection device based on a deuterium-deuterium neutron generator, which is characterized in that: the mine detection device comprises a low-energy neutron absorber, a lead shield, a gamma detector, a source intensity monitoring detector, a neutron reflector, a neutron generator and a neutron moderating body;

The neutron generator is a cylinder and is positioned in the center of the whole device, a neutron generator control cabinet is connected with the neutron generator through a cable, the neutron generator control cabinet provides accelerating high voltage and ion source voltage for the neutron generator, the neutron generator control cabinet is connected with a PC terminal through a network cable, and parameter regulation and control are carried out on the neutron generator control cabinet through control software of the PC terminal; the neutron moderating body is in a disc shape and is tightly attached to the right lower part of the neutron generator; the neutron reflector is a hollow cylinder and is tightly wrapped at the outer sides of the neutron generator and the neutron moderating body; the source intensity monitoring detector is a cylinder and is inserted into the neutron reflector from top to bottom, the power supply module of the source intensity monitoring detector provides high voltage for the source intensity monitoring detector, and a pulse signal measured by the source intensity monitoring detector is converted into a digital signal after being analyzed by the signal acquisition and processing module of the source intensity monitoring detector and is transmitted to the PC terminal;

The lead shielding body is a hollow cylinder with a closed bottom surface, and a cavity of the hollow cylinder deviates from the neutron generator, namely the thickness of the lead shielding body close to one side of the neutron generator is larger than that of the lead shielding body far away from one side of the neutron generator; the gamma detector is placed in a cavity of the lead shielding body, the gamma detector power supply module provides high voltage and low voltage for the gamma detector, and pulse signals measured by the gamma detector are converted into digital signals after linear amplification and pulse amplitude analysis of the gamma detector signal acquisition and processing module and are transmitted to the PC terminal; the low-energy neutron absorber is wrapped on the side surface and the bottom surface of the lead shielding body;

The low-energy neutron absorber, the lead shield and the gamma detector form a detection unit, the detection unit inclines in the vertical direction, and the inclination direction is that the lower end of the detection unit is close to the neutron generator, and the upper end of the detection unit is far away from the neutron generator; the mine detecting device comprises four detecting units which are uniformly and symmetrically distributed in four directions of the side surface of the neutron generator.

The low-energy neutron absorber is made of cadmium, and the thicknesses of cadmium sheets on the side face and the bottom face of the low-energy neutron absorber are both 1mm ~ 2 mm.

The lead shielding body is made of old lead, the thickness of the lead shielding body close to the side of the neutron generator is 3 cm ~ 5cm, the thickness of the lead shielding body far away from the side of the neutron generator is 1 cm ~ 2 cm, and the thickness of the bottom surface of the lead shielding body is 3mm ~ 5 mm.

The gamma detector adopts LaBr₃(Ce) detectors, LaBr₃The diameter and height of the (Ce) crystal were both 7.62 cm.

The source intensity monitoring detector adopts³He is proportional to the count tube.

The neutron generator adopts a deuterium-deuterium neutron generator, and the average energy of emitted neutrons is 2.5 MeV.

The neutron generator adopts a single body structure, namely, the sealed neutron tube, the inverter and the multiplier are fixedly packaged in the interior of the neutron generator in an equipotential mode, and No. 45 transformer oil is used as an insulating, moderating and reflecting material.

The neutron reflector is made of high-density polyethylene, and the side thickness of the neutron reflector is 5cm ~ 8 cm.

the neutron moderating body is made of high-density polyethylene and is 1 cm ~ 4 cm in height.

The thermal neutron analysis mine detection device based on the deuterium and deuterium neutron generator has the following advantages:

First, the use of deuterium neutron generators without any radioactive nuclear material as neutron source, in contrast to conventional deuterium neutron generators²⁵²The difference is that the Cf isotope neutron source is always in a radioactive state, the deuterium-deuterium neutron generator can generate radioactivity only when in work, and the Cf isotope neutron source has the advantages that the emergent beam flow can be adjusted and closed, and the radiation safety is high.

Second, adopt³The He proportional counter tube is used as a source intensity monitoring detector, can monitor the stable state of the beam current emitted by the neutron generator in real time, can be used as the basis for regulating and controlling the parameters of the neutron generator on one hand, and can be used for normalizing and correcting the neutron intensity in a mine detection recognition algorithm on the other hand.

Thirdly, LaBr is adopted₃(Ce) Detector as gamma detector, LaBr compared to conventional BGO and NaI (Tl) detectors₃the (Ce) detector has the advantages of high energy resolution and short luminescence decay time, and can remarkably improve the measurement signal-to-noise ratio of a 10.83 MeV characteristic peak energy area.

Fourthly, four detector array layouts are carried out based on the structure of deuterium neutron generator, and through system structure design and detector array layout optimization, the source neutron utilization rate and the gamma ray detection efficiency are effectively increased, and through multiple shielding of the gamma detector, the radiation background is remarkably reduced, the measurement signal-to-noise ratio is improved, and rapid detection and accurate identification of the underground mine in the soil can be realized.

The thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator adopts the deuterium-deuterium neutron generator as a neutron source, and the emitted beam flow can be adjusted and closed, so that the thermal neutron analysis mine detection device has good radiation safetySex; with the simultaneous use of LaBr₃The (Ce) detector is used as a gamma detector, and has the advantages of high detection efficiency and good energy resolution; through system structure design and detector array layout optimization, effectively increase source neutron utilization ratio and gamma ray detection efficiency to through the multiple shielding to gamma detector, showing and reducing the radiation background, promoting the measurement signal to noise ratio, can realize burying underground mine's quick detection and accurate discernment in the soil.

drawings

FIG. 1 is a schematic structural diagram of a thermal neutron analysis mine detection device based on a deuterium-deuterium neutron generator according to the present invention;

Fig. 2 is a top view of the thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator of the invention.

Fig. 1 is a sectional view taken along line a-a of fig. 2.

In the figure, 1, a low-energy neutron absorber 2, a lead shield 3, a gamma detector 4, a source intensity monitoring detector power supply module 5, a source intensity monitoring detector 6, a neutron reflector 7, a neutron generator 8, a neutron generator target 9, a neutron moderator 10, a source intensity monitoring detector signal acquisition and processing module 11, a neutron generator control case 12, a gamma detector signal acquisition and processing module 13, a gamma detector power supply module 14, a PC terminal 15, a mine 16 and soil.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and examples.

The thermal neutron analysis mine detection device based on the deuterium-deuterium neutron generator comprises a low-energy neutron absorber 1, a lead shielding body 2, a gamma detector 3, a source intensity monitoring detector 5, a neutron reflector 6, a neutron generator 7 and a neutron moderator 9;

The neutron generator 7 is a cylinder and is positioned in the center of the whole device, the neutron generator control cabinet 11 is connected with the neutron generator 7 through a cable, the neutron generator control cabinet 11 provides accelerating high voltage and ion source voltage for the neutron generator 7, the neutron generator control cabinet 11 is connected with the PC terminal 14 through a network cable, and control software of the PC terminal 14 is used for carrying out parameter regulation and control on the neutron generator control cabinet 11; the neutron moderating body 9 is in a disc shape and is tightly attached to the right lower part of the neutron generator 7; the neutron reflector 6 is a hollow cylinder and is tightly wrapped on the outer sides of the neutron generator 7 and the neutron moderator 9; the source intensity monitoring detector 5 is a cylinder and is inserted into the neutron reflector 6 from top to bottom, the source intensity monitoring detector power supply module 4 provides high voltage for the source intensity monitoring detector 5, and a pulse signal measured by the source intensity monitoring detector 5 is converted into a digital signal after being analyzed by the source intensity monitoring detector signal acquisition and processing module 10 and is transmitted to the PC terminal 14;

The lead shielding body 2 is a hollow cylinder with a closed bottom surface, and a cavity of the hollow cylinder deviates from the neutron generator 7, namely the thickness of the lead shielding body 2 close to the neutron generator 7 is larger than that of the lead shielding body 2 far away from the neutron generator 7; the gamma detector 3 is placed in the cavity of the lead shielding body 2, the gamma detector power supply module 13 provides high voltage and low voltage for the gamma detector 3, and pulse signals measured by the gamma detector 3 are converted into digital signals after linear amplification and pulse amplitude analysis of the gamma detector signal acquisition and processing module 12 and are transmitted to the PC terminal 14; the low-energy neutron absorber 1 is wrapped on the side surface and the bottom surface of the lead shielding body 2;

The low-energy neutron absorber 1, the lead shield 2 and the gamma detector 3 form a detection unit, the detection unit tilts in the vertical direction, and the tilting direction is that the lower end of the detection unit is close to the neutron generator 7 and the upper end of the detection unit is far away from the neutron generator 7; the mine detecting device comprises four detecting units which are uniformly and symmetrically distributed in four directions of the side surface of the neutron generator 7.

The low-energy neutron absorber 1 is made of cadmium, and the thicknesses of cadmium sheets on the side face and the bottom face of the low-energy neutron absorber 1 are both 1mm ~ 2 mm.

The lead shielding body 2 is made of old lead, the thickness of the lead shielding body 2 close to the neutron generator 7 is 3 cm ~ 5cm, the thickness of the lead shielding body 2 far away from the neutron generator 7 is 1 cm ~ 2 cm, and the thickness of the bottom surface of the lead shielding body 2 is 3mm ~ 5 mm.

a is describedHorse detector 3 adopts LaBr₃(Ce) detectors, LaBr₃The diameter and height of the (Ce) crystal were both 7.62 cm.

The source intensity monitoring detector 5 adopts³He is proportional to the count tube.

the neutron generator 7 adopts a deuterium-deuterium neutron generator, and the average energy of emitted neutrons is 2.5 MeV.

The neutron generator 7 adopts a single body structure, namely, the sealed neutron tube, the inverter and the multiplier are fixedly packaged in the interior of the neutron generator 7 in an equipotential mode, and No. 45 transformer oil is used as an insulating, moderating and reflecting material.

The neutron reflector 6 is made of high-density polyethylene, and the side thickness is 5cm ~ 8 cm.

The neutron moderating body 9 is made of high-density polyethylene and is 1 cm ~ 4 cm in height.