Step-by-step etching method for extracting extremely trace solar wind 10Be from moon sample

Abstract

The invention provides a step-by-step etching method for extracting an extremely trace amount of solar wind 10Be from a moon sample. Comprising the following steps: 1, screening samples; step 2, etching; step 3, element content analysis; step 4, performing complete digestion; step 5, fluorine removal; step 6, ion exchange; step 7, preparing Be (OH) 2; and step 8, preparing a BeO target sample. According to the method, the etching step length is accurately regulated and controlled by monitoring the element contents of different etching layers, so that fine etching is realized; compared with an existing full dissolution technology, the method is a brand-new step-by-step etching method, and by combining an ion exchange method, layer-by-layer etching of the moon and other extraterrestrial samples and extraction of 10Be in the moon and other extraterrestrial samples are achieved; according to the method, the solar wind injection rate can be determined, and the solar wind injection resource generation rate of the moon and other extraterrestrial celestial bodies can be estimated.

Description

Technical Field

[0001] This invention relates to the extraction of trace amounts of solar wind. 10 Be's methodological field; particularly relating to a method for extracting trace amounts of solar wind from lunar samples. 10 Be's step-by-step etching method. Background Technology

[0002] Currently, lunar and deep space exploration has been listed as one of my country's important strategic development directions. The development and utilization of lunar surface resources are not only an important guarantee for deep space exploration activities, but may also become a key to solving the Earth's energy crisis. Lunar regolith is the main target of lunar scientific exploration and sample return, and also an important source of information for humankind to understand the Moon. The study of lunar regolith not only greatly enriches and expands humankind's understanding of the evolutionary history of the lunar space environment, but more importantly, it has significant implications for the development and utilization of lunar surface resources and even extraterrestrial resources.

[0003] Among the many exploitable resources on the lunar surface, helium-3 holds promise as fuel for nuclear fusion reactors, representing a safe, clean, and efficient energy source. Water ice, on the other hand, can serve as a crucial material and energy source for deep space exploration, particularly manned missions. Both are injected into the lunar surface by the solar wind. Therefore, determining the injection rate of solar wind-carried materials is key to establishing the production capacity of resources like helium-3 and water ice. Unlike stable elements or isotopes in the solar wind, which only reflect the final accumulation effect, cosmogenic radionuclides have definite half-lives, effectively revealing the injection rate and extent of solar wind. Among these, radionuclides such as... 10 Be is an ideal carrier for characterizing the rate of solar wind injection into the lunar surface over the past million years.

[0004] Solar wind is generated by the spallation reactions of trace elements such as C, N, and O in the solar atmosphere. 10 Be(t) 1 / 2 = 1.39 Ma) mainly diffuses into interstellar space through the solar wind, with energy only tens of keV, which can only be injected into the shallow surface layer (hundreds of nanometers) of lunar regolith minerals. The functional relationship between its decay rate and injection rate can trace the process of solar wind injection into lunar regolith on a million-year scale.

[0005] Cosmic origin radionuclides 10 Beta (Be) is a beta-radioactive nuclide. Its million-year half-life and low abundance mean that its measurement is almost entirely dependent on accelerator mass spectrometry (AMS). AMS testing requires preparing the analyte as a powder and pressing it onto a target cone. Currently, for rock samples... 10 Beta measurement, the basic pretreatment technique involves completely dissolving the sample in acid and separating and purifying the solution. 10 Be was measured using AMS. However, this includes both solar wind and solar eclipse. 10 Be (SW)It also includes local causes. 10 Be (in-situ) The two cannot be effectively separated. Using relevant solar wind and lunar regolith surface environmental parameters, as well as the mineral and elemental composition of the lunar regolith, SRIM software can estimate... 10 Be (SW) The injection depth and distribution at different energies are used to determine... 10 Be (SW) Maximum injection depth. 10 Be (SW) The content can be measured by the total amount of lunar soil surface layer. 10 Deducting from Be content 10 Be (in-situ) Based on currently available information, SRIM software estimates... 10 Be (SW) The maximum injection depth is 50-200 nm. Therefore, the goal is to capture the solar wind from the lunar soil. 10 Be (SW) and on the spot 10 Be (in-situ) Separation requires using an acid solution to etch lunar soil particles in steps to a depth of hundreds of nanometers and then extracting the organic matter. 10 Currently, there are no reports on research into this technology in China.

[0006] While NanoSIMS can obtain isotopic content at different depths from the surface to the interior of lunar regolith particles, it is limited in that it can only measure single-particle samples and cannot remove impurities. 10 Be isotopes 10 Interference from B makes it impossible to achieve extremely small amounts of long-lived radionuclides. 10 Be analysis. Therefore, stepwise etching of the sample at the hundred-nanometer scale and extraction of its components were achieved. 10 Be to obtain extremely small amounts of solar wind 10 Be (SW) This is of paramount importance and is the key technical challenge that this invention addresses. Summary of the Invention

[0007] The purpose of this invention is to provide a method for extracting trace amounts of solar wind from lunar samples. 10 Be's step-by-step etching method.

[0008] This invention is achieved through the following technical solution:

[0009] This invention relates to a method for extracting trace amounts of solar wind from lunar samples. 10 The step-by-step etching method for Be includes the following steps:

[0010] Step 1, Sample screening: The sample is screened by vacuum filtration using a sand core filter device; 0.45 μm filter paper is laid on the sand core plate, and the corresponding filter screens are arranged in order of increasing particle size. Rubber rings are placed between the filter screens to ensure tight connection. Finally, a cylindrical graduated funnel is used to press the filter screens together and a special clamp is used to clamp the flange edge to ensure a tight seal.

[0011] (1) Add an appropriate amount of anhydrous ethanol to the sample vial and sonicate for 10 min;

[0012] (2) Soak the filter screen and 0.45 μm filter paper with anhydrous ethanol, slowly transfer the shaken sample onto the filter screen through a dropper, connect the vacuum pump to accelerate the filtration, rinse with anhydrous ethanol and sieve.

[0013] (3) After the sieving is completed, rinse the sample on each filter screen with anhydrous ethanol and transfer it to a centrifuge tube. Place the centrifuge tube in a centrifuge and centrifuge at 3000 rpm for 5 min. Then, discard the supernatant and place the remaining sample in an oven to dry at 60°C until constant weight.

[0014] Step 2, Etching:

[0015] (1) Add 3 ml of a mixture of 5 mM HNO3 and 1 mM HF (or a mixture of 25 mM HNO3 and 5 mM HF, 50 mM HNO3 and 10 mM HF, or 125 mM HNO3 and 25 mM HF) to the centrifuge tube containing the sample, and add 0.6 mg of [the solution]. 9 Be carrier, place centrifuge tubes in a vortex mixer and vortex at 1500 rpm for 15 min, then place them in a centrifuge and centrifuge at 3000 rpm for 5 min, while using a pipette to transfer the supernatant to centrifuge tubes;

[0016] (2) Add 3 ml of ultrapure water to the centrifuge tube containing the precipitate, vortex and centrifuge as described above, transfer the supernatant to the centrifuge tube in the previous step with a pipette, and repeat this step once.

[0017] Step 3, Elemental content analysis: Centrifuge the supernatant obtained in Step 2, take 0.5 ml into a centrifuge tube, add 0.025 g of boric acid, let stand for 1 h, and then adjust the volume. Use AES to measure the content of Al, Ca, Fe, Mg, Si, and Be elements. Calculate the etching quality and Be element recovery rate based on the elemental content. Calculate the etching quality based on the AES measurement results, and then calculate the etching depth based on the etching quality. Adjust the concentration of the HNO3 / HF mixed solution according to the depth requirements of the next etching layer, repeat the etching steps, and cycle until the cumulative etching depth meets the requirements.

[0018] Step 4, complete digestion: Place the undissolved sample in an oven and dry at 80°C until constant weight; pour the dried sample into a PFA digestion vessel and add 0.6 mg of PFA solution. 9 Be carrier was used, and 0.2 ml of HNO3 and 1 ml of HF were added to the digestion vessel. The digestion vessel was then placed on a 150°C heating plate and heated until the sample was completely dissolved. The solution was then evaporated until viscous. The evaporated material was dissolved and the digestion vessel was cleaned with 9 M HCl and pure water and transferred to a centrifuge tube. 0.5 ml of the solution was taken into the centrifuge tube, 0.025 g of boric acid was added, and the solution was left to stand for 1 hour. After adjusting the volume, the content of Al, Ca, Fe, Mg, Si and Be elements was measured using AES.

[0019] Step 5, fluoride removal: Pour all the supernatant into the marked digestion vessel, add 0.25 ml HClO4, evaporate to dryness at 210℃, repeat twice; dissolve the evaporated material and clean the digestion vessel with 9 M HCl in two portions, and transfer to centrifuge tubes;

[0020] Step 6, Ion exchange:

[0021] (1) Add the supernatant to the anion exchange column and collect the Be-containing eluent after Fe removal using a clean PFA digestion vessel;

[0022] (2) After evaporating the Be-containing eluent to near dryness, completely dissolve the evaporated material with 6 M HCl and transfer it to a centrifuge tube. Then rinse the beaker with ultrapure water and transfer the solution to the centrifuge tube.

[0023] (3) Add the solution to the cation exchange column and collect the purified Be eluent in a clean digestion vessel;

[0024] Step 7, Preparation of Be(OH)2:

[0025] (1) Evaporate the Be eluent to near dryness on a heating plate at 210°C, dissolve the evaporated material with 6 M HCl, rinse the digestion vessel with pure water, and transfer it to a centrifuge tube.

[0026] (2) Add ammonia to the solution, place the centrifuge tube on a vortex mixer and vortex for 10-15 seconds, let stand for 30 minutes; place it in a centrifuge and centrifuge at 3000 rpm for 5 minutes, discard the supernatant, and wash the precipitate 3 times with ultrapure water;

[0027] Step 8, BeO target preparation:

[0028] (1) Dissolve the above precipitate with HNO3, transfer it to a quartz crucible, evaporate it to dryness at 150°C on a heating plate, and calcine it at 900°C in a muffle furnace for 2 hours;

[0029] (2) Add equal volumes of BeO and niobium powder to a quartz crucible and mix thoroughly;

[0030] (3) The powder after being mixed evenly is loaded into the target to make the BeO target sample required for accelerator mass spectrometry measurement.

[0031] The present invention has the following advantages:

[0032] (1) This invention utilizes 3 ml of a mixed acid solution with a concentration of 5 mM HNO3 & 1 mM HF (10 mM HNO3 & 2 mM HF or 20 mM HNO3 & 4 mM HF) to achieve stepwise etching of lunar samples or other extraterrestrial celestial body samples with an etching resolution of 100 nm, and extracts the samples from them. 10 Be.

[0033] (2) This invention is based on 3MV AMS. By monitoring the element content of different etching layers in real time, the concentration of etching acid is precisely controlled. In order to avoid the difference in etching rate, the samples are grouped according to the particle size, and a refined step-by-step etching method is established. Combined with ion exchange method to remove interference, step-by-step etching of lunar samples and other extraterrestrial samples at the hundred-nanometer level is achieved. 10 Extraction of Be, from which trace amounts are obtained. 10 Be (SW) This allows us to determine the solar wind injection rate, providing technical support for estimating the generation rate of solar wind injection resources on the Moon and other extraterrestrial bodies.

[0034] (3) This invention can accurately extract trace amounts of substances from lunar or other extraterrestrial samples. 10 Be (SW) The etching step size can be reduced to approximately 100 nm, with a minimum sample mass consumption of about 0.65 mg. This invention enables step-by-step etching of lunar samples at the hundred-nanometer scale. 10 Be was extracted from lunar samples, yielding trace amounts. 10 Be (SW) . Attached Figure Description

[0035] Figure 1 This invention relates to the extraction of trace amounts of solar wind from lunar samples. 10 Flowchart of Be's step-by-step etching method. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are merely further illustrations of the present invention, but the scope of protection of the present invention is not limited to the following embodiments.

[0037] Example

[0038] This embodiment relates to the extraction of trace amounts of solar wind from a lunar simulation sample provided by the National Astronomical Observatories, whose mineral composition, chemical composition, particle size distribution, and other physical properties replicate those of a real lunar sample. 10 For Be's step-by-step etching method, see Figure 1 As shown, this embodiment specifically involves obtaining solar wind from a lunar simulation sample. 10 The concentration of Be;

[0039] Step 1, Sample screening: The sample is screened by vacuum filtration using a sand core filter device; 0.45 μm filter paper is laid on the sand core plate, and the corresponding filter screens are arranged in order of increasing particle size. Rubber rings are placed between the filter screens to ensure tight connection. Finally, a cylindrical graduated funnel is used to press the filter screens together and a special clamp is used to clamp the flange edge to ensure a tight seal.

[0040] (1) Add an appropriate amount of anhydrous ethanol to the sample vial and sonicate for 10 min;

[0041] (2) Soak the filter screen and 0.45 μm filter paper with anhydrous ethanol, slowly transfer the shaken sample onto the filter screen through a dropper, connect the vacuum pump to accelerate the filtration, rinse with anhydrous ethanol and sieve.

[0042] (3) After the sieving is completed, rinse the sample on each filter screen with anhydrous ethanol and transfer it to a centrifuge tube. Place the centrifuge tube in a centrifuge and centrifuge at 3000 rpm for 5 min. Then, discard the supernatant and place the remaining sample in an oven to dry at 60°C until constant weight.

[0043] The lunar soil simulation samples were sieved according to the above method, and 54.5 mg of samples with a particle size of 38-125 μm and 56.8 mg of samples with a particle size of <38 μm were obtained.

[0044] The sieved samples were etched in steps using mixed solutions of HNO3 / HF with different concentrations. The specific acid solution concentration, etching quality, etching depth, and element content of each etching step are shown in Table 1.

[0045] Table 1

[0046]

[0047] The results show that the method established in this invention can achieve stepwise etching of lunar samples at the hundred-nanometer scale, based on the etching layers... 10 Given the atomic concentration of Be and the mass of each layer, calculate the solar wind for each layer. 10 Be concentration and solar wind of the entire sample 10 Be concentration, calculated using the following formula:

[0048]

[0049]

[0050] in, For each etched layer of solar wind 10 Be atomic concentration, For each etched layer 10 Number of Be atoms, For in-situ origin 10 The number of Be atoms, i.e., the number of atoms in the completely digested sample. 10 Number of Be atoms, For the etching quality of each layer, For the solar wind of the entire sample 10 Be atomic concentration, The mass of the fully digested sample.

[0051] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for extracting trace amounts of solar wind from lunar samples 10 The stepwise etching method for Be is characterized by... Includes the following steps: Step 1, Sample screening: (1) Add an appropriate amount of anhydrous ethanol to the sample vial and sonicate for 10 min; (2) Soak the filter screen and 0.45 μm filter paper with anhydrous ethanol, slowly transfer the sample to the filter screen through a dropper, connect the vacuum pump to accelerate the filtration, and rinse and sieve with anhydrous ethanol; (3) After the sieving is completed, rinse the sample on each filter screen with anhydrous ethanol and transfer it to a centrifuge tube. Place the centrifuge tube in a centrifuge and centrifuge at 3000 rpm for 5 min. Then, discard the supernatant and place it in an oven to dry at 60°C until constant weight. Step 2, Etching: (1) Add 3 ml of a mixed solution of HNO3 and HF to the centrifuge tube containing the sample, and add 0.6 mg of HNO3. 9 Be carrier, place centrifuge tubes in a vortex mixer and vortex at 1500 rpm for 15 min, then place them in a centrifuge and centrifuge at 3000 rpm for 5 min, while using a pipette to transfer the supernatant to centrifuge tubes; Among them, the mixed solution of HNO3 and HF is a 5 mM HNO3 and 1 mM HF mixed solution, a 25 mM HNO3 and 5 mM HF mixed solution, a 50 mM HNO3 and 10 mM HF mixed solution, or a 125 mM HNO3 and 25 mM HF mixed solution; (2) Add 3 ml of ultrapure water to the centrifuge tube containing the precipitate, vortex and centrifuge as described above, transfer the supernatant to the centrifuge tube in the previous step with a pipette, and repeat this step once. Step 3, Elemental content analysis: Centrifuge the supernatant obtained in Step 2, take 0.5 ml into a centrifuge tube, add 0.025 g of boric acid, let stand for 1 h, and then adjust the volume. Use AES to measure the content of Al, Ca, Fe, Mg, Si, and Be elements. Calculate the etching quality and Be element recovery rate based on the elemental content. Calculate the etching quality based on the AES measurement results, and then calculate the etching depth based on the etching quality. Adjust the concentration of the HNO3 / HF mixed solution according to the depth requirements of the next etching layer, repeat the etching steps, and cycle until the cumulative etching depth meets the requirements. Step 4, complete digestion: Place the undissolved sample in an oven and dry at 80°C until constant weight; pour the dried sample into a PFA digestion vessel and add 0.6 mg of PFA solution. 9 Be carrier was added to the digestion vessel along with 0.2 ml HNO3 and 1 ml HF. The digestion vessel was then placed on a 150°C heating plate and heated until the sample was completely dissolved. The solution was then evaporated until viscous. The evaporated material was dissolved and the digestion vessel was cleaned with 9 M HCl and pure water and transferred to a centrifuge tube. 0.5 ml of the solution was taken into the centrifuge tube, 0.025 g boric acid was added, and the solution was allowed to stand for 1 hour. After adjusting the volume, the content of Al, Ca, Fe, Mg, Si, and Be elements was measured using AES. Step 5, fluoride removal: Pour all the supernatant into the marked digestion vessel, add 0.25 ml HClO4, evaporate to dryness at 210℃, repeat twice; dissolve the evaporated material and clean the digestion vessel with 9 M HCl in two portions, and transfer to centrifuge tubes; Step 6, Ion exchange: (1) Add the supernatant to the anion exchange column and collect the Be-containing eluent after Fe removal using a clean PFA digestion vessel; (2) After evaporating the Be-containing eluent to near dryness, completely dissolve the evaporated material with 6 M HCl and transfer it to a centrifuge tube. Then rinse the beaker with ultrapure water and transfer the solution to the centrifuge tube. (3) Add the solution to the cation exchange column and collect the purified Be eluent in a clean digestion vessel; Step 7, Preparation of Be(OH)2: (1) Evaporate the Be eluent to near dryness on a heating plate at 210°C, dissolve the evaporated material with 6 M HCl, rinse the digestion vessel with pure water, and transfer it to centrifuge tubes. (2) Add ammonia to the solution, place the centrifuge tube on a vortex mixer and vortex for 10-15 seconds, let stand for 30 minutes; place it in a centrifuge and centrifuge at 3000 rpm for 5 minutes, discard the supernatant, and wash the precipitate 3 times with ultrapure water; Step 8, BeO target preparation: (1) Dissolve the above precipitate with HNO3, transfer it to a quartz crucible, evaporate it to dryness at 150°C on a heating plate, and calcine it at 900°C in a muffle furnace for 2 hours; (2) Add equal volumes of BeO and niobium powder to a quartz crucible and mix thoroughly; (3) The powder after being mixed evenly is loaded into the target to make the BeO target sample required for accelerator mass spectrometry measurement.

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