Neutron measurement system combining dual CMOS sensors with conversion material

Abstract

The application discloses a neutron measurement system combined with a double CMOS sensor and a conversion material, comprising a detector; the detector comprises two CMOS sensors oppositely arranged on a photosensitive surface and a neutron conversion material arranged between the photosensitive surfaces of the two CMOS sensors; the neutron conversion material is used for generating alpha rays by nuclear reaction with neutrons. The application has the advantages that the neutron conversion material is arranged between the two CMOS sensors oppositely arranged on the photosensitive surface, the neutron detection is converted into alpha particle detection which is sensitive to the CMOS sensor, the detection efficiency of neutrons (especially thermal neutrons) is improved, and wide-area neutron measurement angles covering almost the entire spherical space are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron measurement, and in particular to a neutron measurement system combining a dual CMOS sensor and a conversion material. Background Art

[0002] Neutrons are uncharged elementary particles. Due to their magnetic moment and strong penetrating properties, there is a demand for neutron measurement in many fields, including nuclear energy (monitoring the neutron radiation dose received by personnel during the operation and maintenance of nuclear power plants to ensure personnel safety), medicine (precisely measuring the neutron dose around the treatment area in radiotherapy to ensure patient safety), and materials (using neutron diffraction technology to non-destructively obtain information such as the internal crystal phase, grain orientation and size, and residual stress of the material, which is used for mechanism research, processing optimization, and failure assessment of new materials and new components).

[0003] In the field of neutron measurement, neutron detectors based on helium-3 as a working medium are widely used. Helium-3 neutron detectors offer high sensitivity and efficiency. However, with the rapid development of neutron measurement technology, the supply of helium-3 resources has become increasingly scarce, causing the cost of helium-3 neutron detectors to gradually increase. Therefore, the development of neutron detectors based on new neutron measurement materials is urgently needed.

[0004] As alternatives to helium-3 neutron detectors, neutron detectors based on new scintillator materials and semiconductor materials have been developed one after another. However, these neutron detectors often have problems such as large size, high cost, or inability to simultaneously take into account high sensitivity and spatial resolution (i.e., distinguishing the direction of the neutron source). Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a neutron measurement system combining dual CMOS sensors and conversion materials. It solves the problems of existing neutron detectors based on new scintillator materials and semiconductor materials, such as large size, high cost, or inability to achieve both high sensitivity and spatial resolution.

[0006] The technical solution of the present invention is: a neutron measurement system combining dual CMOS sensors and conversion materials, including a detector; the detector includes two CMOS sensors with photosensitive surfaces arranged opposite to each other and a neutron conversion material arranged between the photosensitive surfaces of the two CMOS sensors; the neutron conversion material is used to undergo nuclear reactions with neutrons and generate alpha rays.

[0007] A further technical solution of the present invention is: the neutron conversion material is a three-layer sheet; the three-layer sheet is composed of a neutron conversion layer A, a copper foil and a neutron conversion layer B connected in sequence, the neutron conversion layer A and the neutron conversion layer B respectively facing the photosensitive surfaces of two CMOS sensors, and the neutron conversion layer A and the neutron conversion layer B are respectively placed in contact with or arranged facing the photosensitive surfaces of the opposite CMOS sensors in the air; the thickness of the copper foil does not exceed 1um, the thickness of the neutron conversion layer A is between 500nm and 3um, and the thickness of the neutron conversion layer B is between 500nm and 3um; the distance between the side surface of the neutron conversion layer A connected to the copper foil and the photosensitive surface of the CMOS sensor facing the neutron conversion layer A is less than 2mm; the distance between the side surface of the neutron conversion layer B connected to the copper foil and the photosensitive surface of the CMOS sensor facing the neutron conversion layer B is less than 2mm.

[0008] A further technical solution of the present invention is that the neutron conversion layer A is a two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is 6 Li, the boron element in boron carbide is 10 B; Neutron conversion layer B is two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is 6 Li, the boron element in boron carbide is 10 B.

[0009] A further technical solution of the present invention is: the lithium fluoride is evaporated on the surface of the copper foil by vacuum thermal evaporation coating technology to form the neutron conversion layer A and / or the neutron conversion layer B; the two-dimensional hexagonal boron nitride is deposited on the surface of the copper foil by chemical vapor deposition to form the neutron conversion layer A and / or the neutron conversion layer B; the boron carbide is deposited on the surface of the copper foil by magnetron sputtering to form the neutron conversion layer A and / or the neutron conversion layer B; the 10 The B element is deposited on the surface of the copper foil by magnetron sputtering to form the neutron conversion layer A and / or the neutron conversion layer B.

[0010] A further technical solution of the present invention is that the neutron conversion material is composed of lithium fluoride films respectively attached to the photosensitive surfaces of two CMOS sensors; the lithium element in the lithium fluoride is 6 Li; the thickness of the lithium fluoride film is between 500nm and 3um; the distance between the photosensitive surfaces of the two CMOS sensors is less than 2mm.

[0011] A further technical solution of the present invention is that the lithium fluoride is evaporated on the photosensitive surface of the CMOS sensor using vacuum thermal evaporation coating technology.

[0012] A further technical solution of the present invention is that a layer of moderation material for slowing down fast neutrons into slow neutrons is attached to the bottom surface of the CMOS sensor, and the moderation material is made of paraffin.

[0013] The technical solution of the present invention is: a neutron measurement method applied to the above-mentioned neutron measurement system combining dual CMOS sensors and conversion materials;

[0014] The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, the circuit board is in communication with the chip board, a SoC chip is mounted on the chip board, and the chip board is used to output a frame image containing a radiation response signal; the neutron measurement system comprising a dual CMOS sensor and a conversion material also includes a PC; the PC is in communication with the chip board, and the PC is used to adjust parameters of the CMOS sensor, and store and display frame images containing radiation response signals; for the convenience of subsequent description, the CMOS sensor facing the neutron conversion layer A is defined as CMOS sensor A; the CMOS sensor facing the neutron conversion layer B is defined as CMOS sensor B;

[0015] The method is as follows: when neutrons with a source direction facing the neutron conversion layer A pass through CMOS sensor A and neutron conversion layer A, nuclear reactions occur with target elements in neutron conversion layer A, generating α rays, thereby causing CMOS sensor A to generate a radiation response signal; when neutrons with a source direction facing the neutron conversion layer B pass through CMOS sensor B and neutron conversion layer B, nuclear reactions occur with target elements in neutron conversion layer B, generating α rays, thereby causing CMOS sensor B to generate a radiation response signal; the chip board receives the output data of CMOS sensor A and CMOS sensor B through the SoC chip, processes the data into continuous frame images, and transmits them to a PC; by counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensor corresponding to the frame images, and the orientation of the photosensitive surface of the CMOS sensor, the neutron source direction and the number of neutrons are measured.

[0016] The technical solution of the present invention is: a neutron measurement method applied to the above-mentioned neutron measurement system combining dual CMOS sensors and conversion materials;

[0017] The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, the circuit board is in communication with the chip board, a SoC chip is mounted on the chip board, and the chip board is used to output a frame image containing a radiation response signal; the neutron measurement system combining dual CMOS sensors and conversion materials also includes a PC; the PC is in communication with the chip board, and the PC is used to adjust the parameters of the CMOS sensors, as well as store and display the frame image containing the radiation response signal; for the convenience of subsequent description, the two CMOS sensors are defined as CMOS sensor A and CMOS sensor B;

[0018] The method is as follows: When the neutrons from the source direction facing the bottom surface of CMOS sensor A pass through CMOS sensor A and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating α rays, which in turn causes the CMOS sensor B to generate a radiation response signal; when the neutrons from the direction facing the bottom of the CMOS sensor B pass through the CMOS sensor B and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating alpha rays, which in turn causes CMOS sensor A to generate a radiation response signal. The chip board receives the output data of CMOS sensors A and B through the SoC chip, converts it into continuous frame images, and transmits it to the PC. By counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensor corresponding to the frame images, and the orientation of the photosensitive surface of the CMOS sensor, the direction of the neutron source and the number of neutrons can be measured.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The neutron conversion material is placed between two CMOS sensors with opposing photosensitive surfaces, converting neutron detection into α-particle detection, which is sensitive to the CMOS sensors. This not only improves the detection efficiency of neutrons (especially thermal neutrons), but also achieves a wide-area neutron measurement angle that covers almost the entire spherical space.

[0021] 2. Compared with existing neutron detectors based on new scintillator materials and semiconductor materials, it has the advantages of small size, low manufacturing and use costs, and high sensitivity and spatial resolution (combining the position of the radiation response signal in the frame image, the CMOS sensor corresponding to the frame image, and the orientation of the photosensitive surface of the CMOS sensor to distinguish the direction of the neutron source).

[0022] 3. The entire system is built based on CMOS sensors, which directly output two-dimensional matrix digital signals, facilitate data processing, and are easy to integrate with other electronic systems, making it easy to realize miniaturized, portable, and highly integrated neutron detection equipment.

[0023] The present invention is further described below with reference to the figures and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the detector in Example 1;

[0025] Figure 2 Schematic diagram of the structure of the detector in Example 2.

[0026] Legend: CMOS sensor 1; neutron conversion material 2; copper foil 21; neutron conversion layer A 22; neutron conversion layer B 23; lithium fluoride 24; moderator material 3. DETAILED DESCRIPTION Example 1

[0027] like Figure 1 As shown, the neutron measurement system combining dual CMOS sensors and a conversion material includes a detector. The detector comprises two CMOS sensors 1 with opposing photosensitive surfaces and a neutron conversion material 2 disposed between the photosensitive surfaces of the two CMOS sensors 1. The neutron conversion material 2 is configured to undergo a nuclear reaction with neutrons and generate alpha radiation that excites the CMOS sensors to generate a radiation response signal.

[0028] The neutron conversion material 2 is a three-layer sheet. It consists of a neutron conversion layer A22, a copper foil 21, and a neutron conversion layer B23, connected in sequence. Neutron conversion layer A22 and neutron conversion layer B23 each face the photosensitive surfaces of two CMOS sensors 1. Neutron conversion layer A22 and neutron conversion layer B23 are placed directly opposite the photosensitive surfaces of the opposing CMOS sensors, either directly in contact or spaced apart. The thickness of the copper foil 21 is no more than 1 μm, the thickness of the neutron conversion layer A22 is between 500 nm and 3 μm, and the thickness of the neutron conversion layer B23 is between 500 nm and 3 μm. The distance between the surface of the neutron conversion layer A22 connected to the copper foil 21 and the photosensitive surface of the CMOS sensor 1 facing the neutron conversion layer A22 is less than 2 mm. The distance between the surface of the neutron conversion layer B23 connected to the copper foil 21 and the photosensitive surface of the CMOS sensor 1 facing the neutron conversion layer B23 is less than 2 mm.

[0029] Preferably, whether the neutron conversion layer A22 or the neutron conversion layer B23 and the corresponding photosensitive surface of the CMOS sensor 1 are placed in contact or facing each other in the air, an external fixing structure (support structure) is required to keep the active pixel sensor and the neutron conversion material relatively fixed.

[0030] Preferably, the neutron conversion layer A22 is two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is6 Li, the boron element in boron carbide is 10 B; Neutron conversion layer B23 is two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is 6 Li, the boron element in boron carbide is 10 B.

[0031] Preferably, the lithium fluoride is deposited on the surface of the copper foil 21 by vacuum thermal evaporation coating technology to form the neutron conversion layer A22 and / or the neutron conversion layer B23; the two-dimensional hexagonal boron nitride is deposited on the surface of the copper foil 21 by chemical vapor deposition to form the neutron conversion layer A22 and / or the neutron conversion layer B23; the boron carbide is deposited on the surface of the copper foil 21 by magnetron sputtering to form the neutron conversion layer A22 and / or the neutron conversion layer B23; 10 The B element is deposited on the surface of the copper foil 21 by magnetron sputtering to form the neutron conversion layer A22 and / or the neutron conversion layer B23.

[0032] Preferably, a layer of moderation material 3 for slowing down fast neutrons into slow neutrons is attached to the bottom surface of the CMOS sensor 1 , and the moderation material 3 is made of paraffin wax. The bottom surface is the side opposite to the photosensitive surface.

[0033] Briefly describe the working principle of Example 1:

[0034] A neutron measurement method is applied to the aforementioned neutron measurement system combining dual CMOS sensors and a conversion material. The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, which is communicatively connected to the chip board. The chip board has a SoC chip mounted on it, and the chip board is configured to output a frame image containing a radiation response signal. The neutron measurement system combining dual CMOS sensors and a conversion material further includes a personal computer (PC) communicatively connected to the chip board, configured to adjust parameters of the CMOS sensors and store and display frame images containing radiation response signals. For ease of subsequent description, the CMOS sensor facing neutron conversion layer A is defined as CMOS sensor A, and the CMOS sensor facing neutron conversion layer B is defined as CMOS sensor B.

[0035] The method is as follows: when neutrons with a source direction facing the neutron conversion layer A pass through CMOS sensor A and neutron conversion layer A, nuclear reactions occur with target elements in neutron conversion layer A, generating α rays, thereby causing CMOS sensor A to generate a radiation response signal; when neutrons with a source direction facing the neutron conversion layer B pass through CMOS sensor B and neutron conversion layer B, nuclear reactions occur with target elements in neutron conversion layer B, generating α rays, thereby causing CMOS sensor B to generate a radiation response signal; the chip board receives the output data of CMOS sensor A and CMOS sensor B through the SoC chip, processes the data into continuous frame images, and transmits them to a PC; by counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensor corresponding to the frame images, and the orientation of the photosensitive surface of the CMOS sensor, the neutron source direction and the number of neutrons are measured.

[0036] When the neutron conversion layer A and / or the neutron conversion layer B is the two-dimensional hexagonal boron nitride (2D h-BN), the target element is 10 B; At this time, neutrons and 10 B nuclear reaction is as follows: n+ 10 B → α+ 7 Li+2.792MeV.

[0037] When the neutron conversion layer A and / or the neutron conversion layer B is lithium fluoride (LiF), the target element is 6 Li, at this time, the neutron and 6 The nuclear reaction formula of Li is as follows: n+ 6 Li→α+ 3 T+4.786MeV.

[0038] When the neutron conversion layer A and / or the neutron conversion layer B is the boron carbide (B4C), the target element is 10 B; At this time, neutrons and 10 B nuclear reaction is as follows: n+ 10 B → α+ 7 Li+2.792MeV.

[0039] When the neutron conversion layer A and / or the neutron conversion layer B is 10 When B is a single substance, neutrons and 10 B nuclear reaction is as follows: n+ 10 B → α+ 7 Li+2.792MeV. Example 2

[0040] like Figure 2As shown, the only difference between this embodiment and embodiment 1 is that the neutron conversion material 2 is composed of a lithium fluoride 24 thin film attached to the photosensitive surfaces of the two CMOS sensors 1; the lithium element in the lithium fluoride 24 is 6 The thickness of the lithium fluoride 24 film is between 500 nm and 3 μm; the distance between the photosensitive surfaces of the two CMOS sensors 1 is less than 2 mm.

[0041] Preferably, the lithium fluoride 24 is deposited on the photosensitive surface of the CMOS sensor 1 using vacuum thermal evaporation coating technology.

[0042] Briefly describe the working principle of Example 2:

[0043] A neutron measurement method is applied to the aforementioned neutron measurement system combining dual CMOS sensors and a conversion material. The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, which is communicatively connected to the chip board. The chip board has a SoC chip mounted on it, and the chip board is configured to output a frame image containing a radiation response signal. The neutron measurement system combining dual CMOS sensors and a conversion material further includes a personal computer (PC) communicatively connected to the chip board, configured to adjust CMOS sensor parameters and store and display frame images containing radiation response signals. For ease of description, the two CMOS sensors are defined as CMOS sensor A and CMOS sensor B.

[0044] The method is as follows: When the neutrons from the source direction facing the bottom surface of CMOS sensor A pass through CMOS sensor A and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating α rays, which in turn causes the CMOS sensor B to generate a radiation response signal; when the neutrons from the direction facing the bottom of the CMOS sensor B pass through the CMOS sensor B and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating alpha rays, which in turn causes CMOS sensor A to generate a radiation response signal. The chip board receives the output data of CMOS sensors A and B through the SoC chip, converts it into continuous frame images, and transmits it to the PC. By counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensor corresponding to the frame images, and the orientation of the photosensitive surface of the CMOS sensor, the direction of the neutron source and the number of neutrons can be measured.

[0045] In the above method, neutrons and 6 The nuclear reaction formula of Li is as follows: n+ 6 Li→α+ 3 T+4.786MeV.

Claims

1. A neutron measurement system combining dual CMOS sensors and conversion materials, characterized by: The detector includes two CMOS sensors with photosensitive surfaces arranged opposite to each other and a neutron conversion material disposed between the photosensitive surfaces of the two CMOS sensors; the neutron conversion material is used to undergo a nuclear reaction with neutrons and generate alpha rays; The neutron conversion material is a three-layer sheet; the three-layer sheet consists of a neutron conversion layer A, a copper foil and a neutron conversion layer B connected in sequence. The neutron conversion layer A and the neutron conversion layer B are respectively facing the photosensitive surfaces of the two CMOS sensors. The neutron conversion layer A and the neutron conversion layer B are respectively placed on the photosensitive surfaces of the opposite CMOS sensors or arranged in the air facing each other.

2. The neutron measurement system comprising a dual CMOS sensor and a conversion material as claimed in claim 1, wherein: The thickness of the copper foil does not exceed 1um, the thickness of the neutron conversion layer A is between 500nm and 3um, and the thickness of the neutron conversion layer B is between 500nm and 3um; the distance between the surface of the side where the neutron conversion layer A is connected to the copper foil and the photosensitive surface of the CMOS sensor facing the neutron conversion layer A is less than 2mm; the distance between the surface of the side where the neutron conversion layer B is connected to the copper foil and the photosensitive surface of the CMOS sensor facing the neutron conversion layer B is less than 2mm.

3. The neutron measurement system comprising a dual CMOS sensor and a conversion material as claimed in claim 2, wherein: Neutron conversion layer A is two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is 6 Li, the boron element in boron carbide is 10 B; Neutron conversion layer B is two-dimensional hexagonal boron nitride or lithium fluoride or boron carbide or 10 B element, the boron element in two-dimensional hexagonal boron nitride is 10 B. The lithium element in lithium fluoride is 6 Li, the boron element in boron carbide is 10 B.

4. The neutron measurement system comprising a dual CMOS sensor and a conversion material as claimed in claim 3, wherein: The lithium fluoride is deposited on the surface of the copper foil by vacuum thermal evaporation coating technology to form a neutron conversion layer A and / or a neutron conversion layer B; the two-dimensional hexagonal boron nitride is deposited on the surface of the copper foil by chemical vapor deposition to form a neutron conversion layer A and / or a neutron conversion layer B; the boron carbide is deposited on the surface of the copper foil by magnetron sputtering to form a neutron conversion layer A and / or a neutron conversion layer B; the 10 The B element is deposited on the surface of the copper foil by magnetron sputtering to form the neutron conversion layer A and / or the neutron conversion layer B.

5. The neutron measurement system comprising a dual CMOS sensor and a conversion material according to any one of claims 1 to 4, characterized in that: A layer of moderation material is attached to the bottom surface of the CMOS sensor, which is used to slow down fast neutrons into slow neutrons. The moderation material is made of paraffin.

6. A neutron measurement system combining dual CMOS sensors and conversion materials, characterized by: The detector includes two CMOS sensors with photosensitive surfaces arranged opposite to each other and a neutron conversion material disposed between the photosensitive surfaces of the two CMOS sensors; the neutron conversion material is used to undergo a nuclear reaction with neutrons and generate alpha rays; The neutron conversion material consists of lithium fluoride films attached to the photosensitive surfaces of two CMOS sensors. The lithium element in lithium fluoride is 6 Li.

7. The neutron measurement system comprising a dual CMOS sensor and a conversion material as claimed in claim 6, wherein: The thickness of the lithium fluoride film is between 500nm and 3um; the distance between the photosensitive surfaces of the two CMOS sensors is less than 2mm.

8. The neutron measurement system comprising a dual CMOS sensor and a conversion material as claimed in claim 7, wherein: The lithium fluoride is evaporated on the photosensitive surface of the CMOS sensor using vacuum thermal evaporation coating technology.

9. The neutron measurement system comprising a dual CMOS sensor and a conversion material according to any one of claims 6 to 8, wherein: A layer of moderation material is attached to the bottom surface of the CMOS sensor, which is used to slow down fast neutrons into slow neutrons. The moderation material is made of paraffin.

10. A neutron measurement method, applied to a neutron measurement system comprising a dual CMOS sensor and a conversion material according to any one of claims 1 to 4; wherein: The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, the circuit board is in communication with the chip board, a SoC chip is mounted on the chip board, and the chip board is used to output a frame image containing a radiation response signal; the neutron measurement system comprising a dual CMOS sensor and a conversion material also includes a PC; the PC is in communication with the chip board, and the PC is used to adjust parameters of the CMOS sensor, and store and display frame images containing radiation response signals; for the convenience of subsequent description, the CMOS sensor facing the neutron conversion layer A is defined as CMOS sensor A; the CMOS sensor facing the neutron conversion layer B is defined as CMOS sensor B; The method is as follows: when neutrons from a source direction facing the side of neutron conversion layer A pass through CMOS sensor A and neutron conversion layer A, nuclear reactions occur with target elements in neutron conversion layer A, generating α rays, which in turn cause CMOS sensor A to generate a radiation response signal; when neutrons from a source direction facing the side of neutron conversion layer B pass through CMOS sensor B and neutron conversion layer B, nuclear reactions occur with target elements in neutron conversion layer B, generating α rays, which in turn cause CMOS sensor B to generate a radiation response signal; The chip board receives the output data of CMOS sensor A and CMOS sensor B through the SoC chip, processes it into continuous frame images, and transmits them to the PC. By counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensors corresponding to the frame images, and the orientation of the photosensitive surfaces of the CMOS sensors, the direction of the neutron source and the number of neutrons can be measured.

11. A neutron measurement method, applied to a neutron measurement system comprising a dual CMOS sensor and a conversion material according to any one of claims 6 to 8, characterized in that: The detector further includes a circuit board and a chip board; the CMOS sensor is mounted on the circuit board, the circuit board is in communication with the chip board, a SoC chip is mounted on the chip board, and the chip board is used to output a frame image containing a radiation response signal; the neutron measurement system combining dual CMOS sensors and conversion materials also includes a PC; the PC is in communication with the chip board, and the PC is used to adjust the parameters of the CMOS sensors, as well as store and display the frame image containing the radiation response signal; for the convenience of subsequent description, the two CMOS sensors are defined as CMOS sensor A and CMOS sensor B; The method is as follows: When the neutrons from the source direction facing the bottom surface of CMOS sensor A pass through CMOS sensor A and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating α rays, which in turn causes the CMOS sensor B to generate a radiation response signal; when the neutrons from the direction facing the bottom of the CMOS sensor B pass through the CMOS sensor B and the lithium fluoride film on its photosensitive surface, 6 Li undergoes a nuclear reaction, generating α rays, which in turn causes the CMOS sensor A to generate a radiation response signal; The chip board receives the output data of CMOS sensor A and CMOS sensor B through the SoC chip, processes it into continuous frame images, and transmits them to the PC. By counting the number of radiation response signals, the position of the radiation response signals in the frame images, the CMOS sensors corresponding to the frame images, and the orientation of the photosensitive surfaces of the CMOS sensors, the direction of the neutron source and the number of neutrons can be measured.

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