A High-Resolution Reconstruction Method for Element Distribution Images Based on PGNAA Technology

Abstract

This invention relates to the field of extraterrestrial resource exploration technology, and discloses a high-resolution reconstruction method for elemental distribution images based on PGNAA technology. This method divides the overall detection area into several sub-regions of equal area, measures the types and abundance of elements within the overall detection area using transient gamma-ray neutron activation analysis (PGNAA), and uses the neutron flux information of each sub-region as a boundary condition, combined with the neutron cross-sectional information of each element, to perform inversion calculations on the types and abundance of elements within each sub-region, thereby achieving high-resolution reconstruction of the elemental distribution image within the overall detection area. The method proposed in this invention can reconstruct elemental distribution images from low resolution to high resolution within the detection area. Furthermore, by registering and aligning the obtained high-resolution elemental distribution image with a high-resolution image of the Earth's surface topography, it can obtain the "coloring" information fusion of the surface elemental distribution image of extraterrestrial objects, providing data support for the exploration of the distribution of extraterrestrial resources.

Description

Technical Field

[0001] This invention relates to the field of extraterrestrial resource exploration technology, and in particular to a high-resolution reconstruction method for element distribution images based on PGNAA technology. Background Technology

[0002] Currently, methods for lunar resource exploration include: ① Offline sampling and analysis, which involves drilling and collecting lunar regolith, then returning it to the surface and analyzing its composition using different analytical techniques. The representativeness of the samples limits the application of this technology in large-scale extraterrestrial mineral exploration. ② Online analysis payload measurement, which mainly utilizes lunar orbiters and rovers equipped with various scientific payloads to perform real-time measurement and analysis of lunar regolith composition, ultimately obtaining information on the distribution of lunar resources. However, this technology and its scientific payloads are significantly limited by the extreme lunar environment (including high and low temperatures and complex radiation fields) and spatial distance constraints, resulting in limitations in measurement spatial resolution, depth, and accuracy. Prompt gamma-ray neutron activation analysis (PGNAA) possesses several advantages, including strong penetration, non-destructive nature, online in-situ measurement, and high analytical precision. Based on these technological advantages, corresponding experimental platform payloads can be designed for the exploration of extraterrestrial resource distribution. However, PGNAA technology can only detect the types and contents of all elements within the detection area, but cannot obtain the element composition and contents of each sub-region separately. Therefore, it cannot perform image fusion with high-resolution landform images to provide a surface element distribution image.

[0003] Therefore, for the field of deep space exploration and in response to the needs of extraterrestrial resource exploration, it is indeed necessary to establish a new high-resolution reconstruction method for element distribution images based on PGNAA technology to provide high-resolution surface element distribution images to support extraterrestrial resource exploration. Summary of the Invention

[0004] The purpose of this invention is to address the fields of deep space exploration and extraterrestrial resource exploration. Based on PGNAA technology, a payload experimental platform is constructed to achieve rapid and accurate analysis of the types and contents of elements within the detection area. At the same time, a high-resolution element distribution image reconstruction method is proposed to achieve high-resolution reconstruction of element images within the detection area and registration and alignment with surface images. Ultimately, multi-dimensional image fusion and the construction of surface element distribution images are achieved, providing technical and data support for extraterrestrial resource exploration and demonstrating great practicality.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-resolution reconstruction method for element distribution images based on PGNAA technology includes the following steps:

[0007] Step 1: Design a model of the PGNAA extraterrestrial object detection payload platform based on Monte Carlo simulation software, and build the PGNAA extraterrestrial object detection payload experimental platform according to the model.

[0008] Step 2: Set up the detection area and divide the overall detection area into several sub-regions of equal area; do not place the sample to be tested in the detection area, and calculate the neutron flux of each sub-region based on the PGNAA extraterrestrial object detection payload platform model through Monte Carlo simulation to obtain the neutron flux distribution in the detection area, which is denoted as the standard neutron flux distribution.

[0009] Step 3: Using the aforementioned PGNAA extraterrestrial object detection payload experimental platform, set up the sample to be tested according to the preset sub-region distribution in the Monte Carlo simulation, and use the PGNAA extraterrestrial object detection payload experimental platform to measure the neutron flux of each sub-region to obtain the neutron flux distribution in the detection area, which is denoted as the measured neutron flux distribution.

[0010] Step 4: Utilize the PGNAA extraterrestrial object detection payload experimental platform to measure the sample to be tested within the detection area, and obtain information on the types and contents of elements within the entire detection area; including irradiating the sample with a neutron source and collecting and analyzing characteristic gamma rays using a gamma detector;

[0011] Step 5: Using the standard neutron flux distribution as a benchmark, perform ratio calculation correction on the measured neutron flux distribution to obtain the corrected neutron flux in each sub-region, forming the corrected neutron flux distribution within the detection region;

[0012] Step Six: Construct a system of equations using the element types and their contents within the entire detection area and the neutron flux distribution information within the corrected detection area as boundary conditions. By solving the system of equations, obtain the element types and contents information within each sub-region, and obtain a high-resolution image of the element distribution within the detection area.

[0013] Furthermore, it also includes step seven: matching and aligning the high-resolution image of the element distribution within the detection area with the surface topography image of the detection area to obtain a high-resolution surface "topography-element distribution" fused image.

[0014] Furthermore, the extraterrestrial object PGNAA detection payload platform includes a neutron source, a neutron moderator module, a gamma-ray detector, a neutron detector, a neutron shield, a gamma shield, and a neutron collimation module.

[0015] Furthermore, in step five, the ratio calculation correction for the measured neutron flux distribution is performed using the following formula:

[0016] ;

[0017] In the formula, For the first Corrected neutron flux in each subregion For the first Neutron flux measured in each sub-region For the first Standard neutron flux within each subregion.

[0018] Furthermore, in step six, the system of equations is constructed using the types and contents of elements within the measured detection area and the neutron flux distribution information within the corrected detection area as boundary conditions. The system of equations is as follows:

[0019] ;

[0020] In the formula, For the first Within each sub-region The mass of the element, For the first in the detection area The total mass of the elements, For the first Neutron reaction cross section of a certain element.

[0021] Preferably, the neutron source is any one of a DT neutron generator, a DD neutron generator, an americium-beryllium neutron source, or a californium neutron source.

[0022] Preferably, the gamma-ray detector is any one of a NaI detector, a BGO detector, or a LaBr3 detector.

[0023] Preferably, the neutron detector is any one of a He-3 detector, a BF3 detector, or a fission ionization chamber.

[0024] Preferably, in step one, the Monte Carlo simulation software is any one of Geant4, MCNP, FLUKA, and PHITS.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) This invention proposes a high-resolution element distribution image reconstruction method. Based on the analysis and acquisition of the element composition and content of large-area and large-volume samples using PGNAA technology, the detection area is further subdivided to obtain the accurate element composition and content of each sub-area. This invention provides data support for high-precision resource exploration.

[0027] (2) The high-resolution element distribution image obtained by the present invention can be further matched and combined with high-resolution images (such as surface topography images) obtained by other technologies in deep space exploration, so as to obtain a corresponding fused image. For example, the high-resolution image of element distribution in the detection area obtained by the present invention is matched and aligned with the surface topography image of the detection area to obtain a high-resolution surface "topography-element distribution" fused image. Attached Figure Description

[0028] Figure 1 This is a flowchart of the steps in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the extraterrestrial body PGNAA detection payload platform model structure according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the experimental platform for detecting extraterrestrial objects (PGNAA) payloads according to an embodiment of the present invention during its use.

[0031] Figure 4 This is a high-resolution distribution image of iron elements within the detection area obtained in an embodiment of the present invention;

[0032] Figure reference numerals: 1. DD DC neutron generator; 2. Gamma ray detector; 3. Gamma shield; 4. Neutron shield; 5. Neutron moderation module; 6. Neutron collimation module; 7. Experimental load platform; 8. Lunar soil sample; 9. Neutron detector. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0036] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] Reference Figure 1 A high-resolution reconstruction method for element distribution images based on PGNAA technology includes the following steps:

[0039] Step 1: Design a model of the PGNAA extraterrestrial object detection payload platform based on Monte Carlo simulation software, and then build an experimental platform for the PGNAA extraterrestrial object detection payload based on the designed model.

[0040] Specifically, a model of the PGNAA extraterrestrial object detection payload experimental platform was designed based on the Monte Carlo MCNP simulation software. The structure of the PGNAA extraterrestrial object detection payload experimental platform model is referenced. Figure 2 The model includes: 1. DD DC neutron generator, 2. γ-ray detector, 3. γ-ray shield, 4. neutron shield, 5. neutron moderation module, 6. neutron collimation module, 7. experimental load platform, 8. lunar soil sample, and 9. neutron detector.

[0041] Among them, the DD DC neutron generator 1 is the neutron source of the experimental platform. Its main function is to emit neutrons. The emitted neutron energy is about 2.45 MeV. The neutron emission direction is 4π. The neutrons enter the simulated lunar soil environment and react with the elements in lunar soil sample 8, and emit characteristic gamma rays in a short time. Lunar soil sample 8 mainly includes hydrogen (H), iron (Fe), titanium (Ti), silicon (Si), carbon (C), magnesium (Mg), oxygen (O) and sodium (Na). Since each element has a different excitation energy level, the characteristic energy of the gamma rays emitted by its reaction with neutrons is also different.

[0042] Among them, the gamma-ray detector 2 is used to collect the characteristic gamma rays emitted by the reaction of neutrons with each element in lunar soil sample 8. By collecting the characteristic gamma rays, the gamma energy spectrum can be obtained. The gamma-ray detector 2 is a bismuth germanate (BGO) detector.

[0043] The neutron moderation module 5 is placed between the DD DC neutron generator 1 and the lunar soil sample. Its main function is to moderate the emitted neutrons with an energy of 2.45 MeV and obtain a certain amount of thermal neutrons to ensure the efficiency of the thermal neutron capture reaction. The main material of the neutron moderation module 5 is polyethylene.

[0044] Among them, the γ shield 3 and the neutron shield 4 are placed between the DD DC neutron generator 1 and the γ ray detector 2. Their main function is to shield neutrons and γ rays generated in other directions from entering the detector, suppress the detector background, and thus improve the signal-to-noise ratio of the overall system. The material of the γ shield 3 is lead, and the material of the neutron shield 4 is boron-containing polyethylene.

[0045] Among them, the neutron collimation module 6 is mainly placed on both sides of the neutron moderation module 5 in the horizontal direction. Its main function is to increase the neutron flux at the lunar soil sample 8 through scattering, while reducing the reaction probability of neutrons outside the lunar soil sample 8, thereby improving the signal-to-noise ratio of the system. The material of the neutron collimation module 6 is lead.

[0046] Among them, the neutron detector 9 is placed below the experimental load platform 7 and close to the lunar soil sample 8. Its main function is to measure the neutron flux in each sub-region and provide data support for subsequent corrections. The neutron detector 9 is a He-3 detector.

[0047] Among them, the experimental load platform 7 mainly serves to support the overall experimental device and facilitate the movement of the experimental device during the measurement process.

[0048] The experimental platform for detecting extraterrestrial objects (PGNAA) payloads, built under the guidance of the PGNAA payload platform model, is as follows: Figure 3 As shown, its structure is consistent with the PGNAA extraterrestrial object detection payload platform model.

[0049] Step 2: Set the detection area range by dividing the overall detection area into sub-regions of equal area. No samples are placed within the detection area. Using Monte Carlo simulation based on the designed PGNAA extraterrestrial object detection payload platform model, the neutron flux distribution of each sub-region under these model conditions is calculated and denoted as the standard neutron flux distribution.

[0050] Specifically, the neutron source is generally considered to be a point source, with the emission direction in the 4π direction. As the distance increases, the neutron flux within a sub-region inevitably decreases, and the attenuation of neutron flux follows the inverse square law of distance. In the Monte Carlo simulation, based on the sub-region distribution, the neutron flux in each sub-region is calculated using an Fmesh recording card, thereby obtaining the neutron flux distribution of each sub-region under the model conditions, denoted as the standard neutron flux distribution.

[0051] Step 3: Using the PGNAA extraterrestrial object detection payload experimental platform, set up the sample to be tested according to the preset sub-region distribution in the Monte Carlo simulation. Measure the neutron flux in different sub-regions using the PGNAA experimental platform to obtain the neutron flux distribution within the detection area, denoted as the measured neutron flux distribution;

[0052] Specifically, based on the sub-regional distribution of the detection area preset in the Monte Carlo simulation, lunar soil sample 8 is placed within the detection area to simulate the lunar soil environment. A neutron detector 9 is placed above the lunar soil sample 8 in the sub-region. Neutrons enter the neutron detector and react with He-3 gas, generating electrical signals that are collected and recorded by a single-channel counter. The neutron count within the region, i.e., the neutron flux, can then be statistically analyzed. The neutron detector 9 is placed in different sub-regions for measurement to obtain the neutron flux distribution within the detection area, which is denoted as the measured neutron flux distribution.

[0053] Step 4: Measure lunar soil sample 8 using the PGNAA extraterrestrial object detection payload experimental platform, irradiate lunar soil sample 8 in the detection area using DD DC neutron generator 1, collect and analyze characteristic gamma rays using gamma ray detector 2, and obtain information on the types and contents of elements in the detection area.

[0054] Specifically, since the neutron excitation energy levels of each element in lunar soil sample 8 are different, the energy of the gamma rays generated during de-excitation is also different, and there is a certain positive correlation between the number of characteristic gamma rays and the number of elements. Therefore, the gamma ray energy spectrum is obtained by gamma ray detector 2, and the types and contents of elements in the detection area are analyzed based on the energy and intensity information of each characteristic peak.

[0055] Step 5: Using the standard neutron flux distribution as a benchmark, perform ratio calculation correction on the measured neutron flux distribution to obtain the corrected neutron flux in each sub-region, thus forming the corrected neutron flux distribution in the detection region.

[0056] Specifically, the formula for calculating the neutron flux distribution within the modified detection region is as follows:

[0057] ;

[0058] In the formula, For the first Corrected neutron flux in each subregion For the first Neutron flux measured in each sub-region For the first Standard neutron flux within each subregion.

[0059] Step 6: Construct a set of equations using the measured element types and contents within the detection area and the corrected neutron flux distribution information within the detection area as boundary conditions. By solving the set of equations, obtain the element types and contents information within each sub-region, and realize the reconstruction of the element distribution image within the detection area from low resolution to high resolution.

[0060] Specifically, the system of equations is as follows:

[0061] ;

[0062] In the formula, For the first Within each sub-region The mass of the element, For the first in the detection area The total mass of the elements, For the first Neutron reaction cross section of a certain element;

[0063] The known information in the system of equations is the corrected neutron flux within a subregion. Elemental neutron reaction cross section and the total mass of elements within the detection area calculated based on step four. The unknown information is the quality of elements within each sub-region. By performing inversion calculations on the above equations, the types and contents of elements in each sub-region of the detection area can be obtained, thus realizing the reconstruction of the element distribution image in the detection area from low resolution to high resolution.

[0064] High-resolution distribution image of iron (Fe) in the detection area, as shown below Figure 4 As shown, it is clear that the distribution of iron (Fe) in the detection area can be obtained through image reconstruction. Areas with higher gray values ​​are areas with higher iron (Fe) content, while areas with lower gray values ​​are areas with lower iron (Fe) content.

[0065] Step 7: Match and align the high-resolution image of element distribution within the detection area with the surface topography image to obtain a high-resolution surface "topography-element distribution" fused image.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for high resolution reconstruction of elemental distribution images based on PGNAA technique, characterized in that, The method comprises the following steps: Step one: design an extraterrestrial object PGNAA detection load platform model based on Monte Carlo simulation software, and guide the construction of an extraterrestrial object PGNAA detection load experimental platform according to the extraterrestrial object PGNAA detection load platform model; Step two: set a detection area, divide the whole detection area into a plurality of sub-areas with equal area, do not place a sample to be tested in the detection area, calculate the neutron flux of each sub-area based on the extraterrestrial object PGNAA detection load platform model through Monte Carlo simulation, and obtain the neutron flux distribution in the detection area, which is recorded as a standard neutron flux distribution; Step three: use the extraterrestrial object PGNAA detection load experimental platform, set the sample to be tested according to the preset sub-area distribution in the Monte Carlo simulation, and measure the neutron flux of each sub-area by using the extraterrestrial object PGNAA detection load experimental platform to obtain the neutron flux distribution in the detection area, which is recorded as a measured neutron flux distribution; Step four: measure the sample to be tested in the detection area by using the extraterrestrial object PGNAA detection load experimental platform to obtain the element type and content information in the whole detection area; It comprises irradiating the sample by using a neutron source, collecting and analyzing characteristic gamma rays by using a gamma detector; Step five: take the standard neutron flux distribution as a benchmark to correct the measured neutron flux distribution by ratio calculation, obtain the corrected neutron flux of each sub-area, and form the neutron flux distribution in the corrected detection area; Step six: take the obtained element type and content in the whole detection area and the neutron flux distribution information in the corrected detection area as boundary conditions to construct an equation group, solve the equation group to obtain the element type and content information in each sub-area, and obtain a high-resolution image of the element distribution in the detection area.

2. The elemental distribution image high-resolution reconstruction method based on PGNAA technology according to claim 1, characterized in that, It further comprises step seven: matching and aligning the obtained high-resolution image of the element distribution in the detection area with a topographic image of the detection area to obtain a high-resolution topographic-element distribution fusion image.

3. The elemental distribution image high resolution reconstruction method based on PGNAA technology according to claim 2, characterized in that, The extraterrestrial object PGNAA detection load platform comprises a neutron source, a neutron moderator, a gamma ray detector, a neutron detector, a neutron shielding body, a gamma shielding body, and a neutron collimation module.

4. The elemental distribution image high resolution reconstruction method based on PGNAA technology according to claim 3, characterized in that, In step five, the correction of the measured neutron flux distribution by ratio calculation is calculated by the following formula: ； In the formula, For the first Corrected neutron flux in each subregion For the first Neutron flux measured in each sub-region For the first Standard neutron flux within each subregion.

5. The elemental distribution image high resolution reconstruction method based on PGNAA technique according to claim 4, characterized in that, In step six, the equation group is constructed by taking the obtained element type and content in the whole detection area and the neutron flux distribution information in the corrected detection area as boundary conditions. ； In the formula, For the first Within each sub-region The mass of the element, For the first in the detection area The total mass of the elements, For the first Neutron reaction cross section of a certain element.

6. The elemental distribution image high resolution reconstruction method based on PGNAA technique according to claim 2, characterized in that, The neutron source is any one of a D-T neutron generator, a D-D neutron generator, an americium-beryllium neutron source, or a californium neutron source.

7. The elemental distribution image high resolution reconstruction method based on PGNAA technology according to claim 6, characterized in that, The gamma ray detector is any one of a NaI detector, a BGO detector, or a LaBr3 detector.

8. The elemental distribution image high resolution reconstruction method based on PGNAA technology according to claim 7, characterized in that, The neutron detector is any one of a He-3 detector, a BF3 detector, or a fission ionization chamber.

9. The elemental distribution image high resolution reconstruction method based on PGNAA technique according to claim 2, characterized in that, In step one, the Monte Carlo simulation software adopts any one of Geant4, MCNP, FLUKA, and PHITS.

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