CN117991392A - Detection system - Google Patents
Detection system Download PDFInfo
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- CN117991392A CN117991392A CN202410033964.XA CN202410033964A CN117991392A CN 117991392 A CN117991392 A CN 117991392A CN 202410033964 A CN202410033964 A CN 202410033964A CN 117991392 A CN117991392 A CN 117991392A
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- 238000001514 detection method Methods 0.000 title claims abstract description 131
- 230000005855 radiation Effects 0.000 claims description 13
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 5
- 229910052796 boron Inorganic materials 0.000 claims description 5
- -1 polyethylene structure Polymers 0.000 claims description 5
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical group [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 4
- 238000004891 communication Methods 0.000 claims description 3
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 239000011824 nuclear material Substances 0.000 abstract description 17
- 230000000712 assembly Effects 0.000 description 12
- 238000000429 assembly Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000000523 sample Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000011162 core material Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000004992 fission Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 239000002915 spent fuel radioactive waste Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
- G01N23/025—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material using neutrons
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measurement Of Radiation (AREA)
Abstract
The application relates to the technical field of nuclear material detection, and provides a detection system, which comprises a neutron source component and a plurality of detection components, wherein the neutron source component comprises a neutron source, a fast neutron beam emitted by the neutron source is slowed down to form a thermal neutron beam, the thermal neutron beam irradiates a detection object, the detection components receive thermal neutrons, the detection components are arranged along a first direction to form a first unit, the detection components are modularized, the neutron source component is arranged on one side of the detection object along the first direction or one side of the detection object far away from the first unit along a second direction, so that the arrangement modes of the detection components and the neutron source component are flexible, the arrangement mode can be changed according to the category of the detection object, and the application range of the detection system is enlarged.
Description
Technical Field
The application relates to the technical field of nuclear material detection, in particular to a detection system.
Background
The special core material (Special Nuclear Materials, SNM) is the core material for the preparation of core devices, which have extremely strong destructive power and high radiation damage.
In the related art, a detection system for a special nuclear material adopts passive detection, and the passive detection is to directly detect a ray bundle emitted by the SNM itself to determine whether to conceal the SNM. However, passive detection is difficult in the case that the energy of the beam emitted by the SNM itself is weak, resulting in limited application scenarios of the detection system in the related art.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a detection system that can increase the application range of the detection system.
An embodiment of the present application provides a detection system including:
the neutron source assembly comprises a neutron source, wherein a fast neutron beam emitted by the neutron source is slowed down to form a thermal neutron beam, and the thermal neutron beam irradiates a detection object;
the neutron source assembly is arranged on one side of the detection object along the first direction or one side of the detection object away from the first unit along the second direction, wherein the first direction is perpendicular to the second direction.
In some embodiments, the two first units are arranged at intervals along the second direction to form an avoidance space, the detection object is located in the avoidance space, and the neutron source assembly is arranged on one side of the detection object along the first direction.
In some embodiments, the detection system includes a shielding case disposed on opposite sides of the first unit in the second direction.
In some embodiments, the shield shell is a cadmium structure.
In some embodiments, the detection assembly includes a detector and a moderator formed with a receiving cavity, the detector disposed within the receiving cavity such that thermal neutrons are transferred to the detector.
In some embodiments, the moderator is cylindrical and/or hexahedral.
In some embodiments, a circumferential surface of the probe mates with an inner wall surface of the moderator.
In some embodiments, the neutron source assembly includes a shield defining a shield cavity therein, the shield having a radiation aperture facing the detection object, the radiation aperture in communication with the shield cavity, the neutron source disposed within the shield cavity, the fast neutron beam irradiating the detection object through the radiation aperture.
In some embodiments, the shield is a boron-containing polyethylene structure.
In some embodiments, the shielding member has a hexahedral shape opening toward the detection object.
On one hand, compared with a passive detection mode, the detection system provided by the embodiment of the application adopts an active detection mode that a fast neutron beam emitted by a neutron source is slowed down to form a thermal neutron beam, and the thermal neutron beam irradiates a detection object, so that the detection system has high penetrating power and high sensitivity, and can be used for the situation that the energy of a ray bundle emitted by an SNM is weaker. On the other hand, the plurality of detection assemblies are arranged along the first direction to form the first unit, so that the plurality of detection assemblies are modularized, the neutron source assemblies are arranged on one side of the detection object along the first direction, such as the front-rear direction, or on one side of the detection object, such as the left-right direction, away from the first unit, so that the arrangement modes of the detection assemblies and the neutron source assemblies are flexible, the arrangement modes can be changed according to the types of the detection object, and the application range of the detection system is enlarged.
Drawings
FIG. 1 is a schematic diagram of a portion of a detection system according to some embodiments of the present application;
FIG. 2 is a schematic diagram of a portion of a detection system according to other embodiments of the present application;
FIG. 3 is a schematic diagram of a moderator according to some embodiments of the present application;
FIG. 4 is a schematic view of a shield according to some embodiments of the application;
FIG. 5 is a schematic representation of an attenuation curve of neutron counts in accordance with some embodiments of the application;
fig. 6 is a schematic diagram of a detection system according to some embodiments of the application.
Description of the reference numerals
A detection system 100; a neutron source assembly 10; a neutron source 11; a shield 12; a shielding cavity 12a; a discharge hole 12b; a detection assembly 20; a detector 21; a moderator 22; a housing chamber 22a; a first unit 30; an avoidance space 30a; a detection object 40; a shield case 50; a controller 60; a data processing device 70.
Detailed Description
Embodiments of the present application are described in further detail below with reference to the accompanying drawings and examples. The following examples are illustrative of the application but are not intended to limit the scope of the application.
The various features and embodiments described in the detailed description may be combined in any suitable manner, for example, different embodiments may be formed by different combinations of features/embodiments, where not contradictory, and various possible combinations of features/embodiments in the present application are not described further in order to avoid unnecessary repetition.
In the present application, one of the first direction and the second direction may be a front-rear direction, and the other of the first direction and the second direction may be a left-right direction. The lower direction is the direction toward the ground, the upper direction is the opposite direction to the lower direction, the front direction is the direction of the detection object 40 toward the user, and the rear direction is the opposite direction to the front direction; left means the side where the left hand is located in the case where the user is located on the front side of the detection object 40, and right is the opposite direction to the left; the front-back direction, the left-right direction and the up-down direction are mutually perpendicular to form a three-dimensional vertical coordinate system.
The present application provides a detection system 100 for detecting a particular nuclear material, see fig. 1 and 2. The detection system 100 includes a neutron source assembly 10 and a plurality of detection assemblies 20, the neutron source assembly 10 includes a neutron source 11, a fast neutron beam emitted by the neutron source 11 is moderated to form a thermal neutron beam, the thermal neutron beam irradiates a detection object 40, the detection assemblies 20 receive thermal neutrons, the plurality of detection assemblies 20 are arranged along a first direction to form a first unit 30, and the neutron source assembly 10 is disposed on one side of the detection object 40 along the first direction or one side of the detection object away from the first unit 30 along a second direction, wherein the first direction and the second direction are perpendicular. Specifically, the detection object 40 is located on one side of the plurality of detection assemblies 20 in the second direction.
The present application adopts an active detection method of a special nuclear material, wherein the active detection method is to induce the nuclear material in the detection object 40 to generate fission, photo-induced fission or nuclear resonance fluorescence by an external radiation source, and identify the special nuclear material by detecting a characteristic signal. The detection system 100 is based on a differential attenuation analysis technology, that is, after the neutron source 11 emits a fast neutron beam, the fast neutrons will attenuate gradually, that is, the thermal neutrons will attenuate gradually, and the detection assembly 20 receives the thermal neutrons attenuated gradually and outputs a characteristic signal, so as to determine whether the special nuclear material exists in the detection object 40 according to the characteristic signal and the duration of the thermal neutrons.
Referring to fig. 5, a fast neutron beam emitted from a neutron source 11 is moderated to form a thermal neutron beam, the thermal neutron beam irradiates a detection object 40, and a detection assembly 20 captures the moderated thermal neutron beam and generates a characteristic signal. When no special nuclear material is contained in the detection object 40, no new fast neutrons are generated. When the special nuclear material is contained in the detection object 40, the thermal neutrons induce the special nuclear material to be fissiled, so that new fast neutrons are generated, and more thermal neutrons are generated after being moderated, so that the number of thermal neutrons captured by the detection assembly 20 is increased relative to the former case (i.e. the case without the special nuclear material), and the duration of the characteristic signal of the latter is longer relative to the former, in other words, the characteristic signal of the latter is stronger in the same time period relative to the former. In this way, the presence or absence of the special nuclear material in the test object 40 is ascertained from the characteristic signal of the thermal neutrons and the duration thereof.
In fig. 5, the solid line represents the attenuation curve of the neutron count of the detection object 40 containing no special nuclear material, and the broken line represents the attenuation curve of the neutron count of the detection object 40 containing the special nuclear material.
Illustratively, the neutron source 11 may be a pulsed neutron source that emits fast neutron beams at intervals that are more advantageous for detecting the presence or absence of particular nuclear material in the test object 40 than continuous fast neutron beams that continuously form thermal neutrons.
In one aspect, compared with a passive detection mode, the detection system 100 provided in the embodiment of the application adopts an active detection mode of irradiating the detection object 40 with fast neutron beams emitted by the neutron source 11 to form thermal neutron beams, has high penetrating power and high sensitivity, and can be used in the case that the energy of the ray beams emitted by the SNM itself is weak. On the other hand, the plurality of detection assemblies 20 are arranged along the first direction to form the first unit 30, so that the plurality of detection assemblies 20 are modularized, the neutron source assembly 10 is arranged on one side of the detection object 40 along the first direction, such as the front-back direction, or on one side of the detection object 40 away from the first unit 30 along the second direction, such as the left-right direction, so that the arrangement modes of the detection assemblies 20 and the neutron source assembly 10 are flexible, the arrangement modes can be changed according to the types of the detection object 40, and the application range of the detection system 100, such as fissile material residues of a spent fuel post-treatment plant, metal hulls during spent fuel transportation, a nuclear waste bucket and the like, is enlarged.
In some embodiments, referring to fig. 2, two first units 30 are disposed at intervals along the second direction to form an avoidance space 30a, the detection object 40 is located in the avoidance space 30a, and the neutron source assembly 10 is disposed on one side of the detection object 40 along the first direction. In this manner, the capture of thermal neutrons by the detection assembly 20 may be improved, improving the accuracy of the detection system 100.
For example, the detection object 40 is a regular hexahedron with a side length of 30 cm, and the distance between the two first units 30 may be 50 cm, that is, the distance between the side surface of the detection object 40 along the left-right direction and the first units 30 is 10 cm, so that the number of thermal neutrons received by the detection assembly 20 can be increased, and the accuracy of the detection system 100 can be improved. Furthermore, the suitability of the detection system 100 is improved by optimizing the layout by adjusting the distance between the neutron source assembly 10 and the detection object 40 and/or adjusting the spacing between the two first units 30 for different detection objects 40.
In other embodiments, the neutron source assembly 10 is disposed in the avoidance space 30a, that is, the distance between the neutron source assembly 10 and the detection object 40 is further reduced, so that the loss of the fast neutron beam during the transmission process can be reduced.
In some embodiments, referring to fig. 1 and 2, the detection system 100 includes a shielding case 50, and the shielding case 50 is disposed on opposite sides of the first unit 30 along the second direction. In this way, interference of free neutrons in the environment with lower energy values, e.g., 0.025eV (electron volts), can be shielded, improving the accuracy of the detection assembly 20.
In some embodiments, the shield 50 is a cadmium structure. That is, the material of the shield shell 50 includes cadmium. In this manner, the neutron capture cross section of the detection assembly 20 is increased, thereby enhancing the thermal neutron capture performance of the detection assembly 20 and improving the accuracy of the detection system 100.
In some embodiments, the shielding case 50 has a flat plate shape, and the shielding case 50 covers a side surface of the first unit 30 in the first direction.
In some embodiments, referring to fig. 1 to 3, the detecting assembly 20 includes a detector 21 and a slowing member 22, the slowing member 22 is formed with a receiving cavity 22a, and the detector 21 is disposed in the receiving cavity 22a such that thermal neutrons are transferred to the detector 21. The moderating member 22 can further moderate the thermal neutrons so that the thermal neutrons are uniformly transmitted to the detector 21, thereby improving the detection performance of the detector 21.
For example, referring to fig. 3, the moderator 22 is formed with an opening in communication with the receiving chamber 22a, through which the probe 21 can be moved into and out of the receiving chamber 22a, improving the ease of loading and unloading the probe assembly 20.
The type of detector 21 is not limited and may be, for example, 3 He detector, which is beneficial for accurate detection of neutrons because 3 He detector is insensitive to other types of radiation, such as gamma rays.
The material of the slowing member 22 is not limited, and may be polyethylene, for example.
In some embodiments, the moderator 22 is cylindrical and/or hexahedral. In this way, the moderator 22 is structurally stable as a whole.
Illustratively, referring to FIG. 3, the moderator 22 is cylindrical in shape and, because of the absence of corners in the cylindrical structure, enhances the safety of the first unit 30 during handling.
In some embodiments, the circumferential surface of the probe 21 mates with the inner wall surface of the moderator 22. In other words, the moderator 22 wraps around the circumferential surface of the probe 21. In this manner, the stability of the probe assembly 20 is enhanced.
In some embodiments, referring to fig. 1, 2 and 4, the neutron source assembly 10 includes a shielding member 12, a shielding cavity 12a is defined inside the shielding member 12, the shielding member 12 has a radiation hole 12b facing the detection object 40, the radiation hole 12b communicates with the shielding cavity 12a, the neutron source 11 is disposed in the shielding cavity 12a, and the fast neutron beam irradiates the detection object 40 through the radiation hole 12 b. The shield 12 reduces the impact of the fast neutron beam generated by the neutron source 11 on the surrounding environment. The radiation hole 12b facilitates the fast neutron beam to exit the shield 12 in a specific direction without interference from the shield 12.
In some embodiments, the shield 12 is a boron-containing polyethylene structure. That is, the material of the shield 12 includes boron-containing polyethylene. In this way, shields 12 of different boron content can be formulated to improve the suitability of the detection system.
In some embodiments, referring to fig. 1, 2 and 4, the shielding member 12 has a hexahedral shape that is open toward the object under test 40. Thus, the device is easy to process and manufacture and can be stably placed on a horizontal plane.
In some embodiments, referring to FIG. 6, neutron source assembly 10 includes a controller 60. The controller 60 is electrically connected to the neutron source 11, and the controller 60 is configured to send a pulse signal to the neutron source 11, so that the neutron source 11 emits a pulsed fast neutron beam.
In some embodiments, referring to FIG. 6, neutron source assembly 10 includes a data processing device 70. The data processing device 70 is electrically connected to the controller 60 and the detector 21, respectively, and the data processing device 70 receives the characteristic signals transmitted by the detector 21 and processes the characteristic signals to obtain a schematic diagram of the graph shown in fig. 5, for example. Meanwhile, the controller 60 synchronously transmits pulse signals to the data processing device 70, so that the data processing device 70 receives the characteristic signals and the neutron source 11 transmits the pulse fast neutron beams with the same frequency, thereby improving the accuracy of the detection system 100.
In the description of the present specification, reference to the terms "some embodiments," "other embodiments," and "exemplary" etc. means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
The various embodiments/implementations provided by the application may be combined with one another without contradiction. The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. A detection system, comprising:
the neutron source assembly comprises a neutron source, wherein a fast neutron beam emitted by the neutron source is slowed down to form a thermal neutron beam, and the thermal neutron beam irradiates a detection object;
the neutron source assembly is arranged on one side of the detection object along the first direction or one side of the detection object away from the first unit along the second direction, wherein the first direction is perpendicular to the second direction.
2. The detection system of claim 1, wherein two of the first units are disposed at intervals along the second direction to form an avoidance space, the detection object is located in the avoidance space, and the neutron source assembly is disposed at one side of the detection object along the first direction.
3. The detection system of claim 1, wherein the detection system comprises a shielding shell disposed on opposite sides of the first unit in the second direction.
4. The detection system of claim 3, wherein the shield is a cadmium structure.
5. The detection system of claim 1, wherein the detection assembly includes a detector and a moderator, the moderator being formed with a receiving cavity, the detector being disposed within the receiving cavity such that thermal neutrons are transferred to the detector.
6. The detection system according to claim 5, wherein the slowing-down member is cylindrical and/or hexahedral.
7. The detection system of claim 5, wherein a circumferential surface of the detector mates with an inner wall surface of the moderator.
8. The detection system of claim 1, wherein the neutron source assembly includes a shield defining a shield cavity therein, the shield having a radiation aperture oriented toward the detection object, the radiation aperture in communication with the shield cavity, the neutron source disposed within the shield cavity, the fast neutron beam irradiating the detection object through the radiation aperture.
9. The detection system of claim 8, wherein the shield is a boron-containing polyethylene structure.
10. The detection system according to claim 8, wherein the shielding member has a hexahedral shape opening toward the detection object.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410033964.XA CN117991392A (en) | 2024-01-09 | 2024-01-09 | Detection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410033964.XA CN117991392A (en) | 2024-01-09 | 2024-01-09 | Detection system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117991392A true CN117991392A (en) | 2024-05-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410033964.XA Pending CN117991392A (en) | 2024-01-09 | 2024-01-09 | Detection system |
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| CN (1) | CN117991392A (en) |
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- 2024-01-09 CN CN202410033964.XA patent/CN117991392A/en active Pending
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