A composite shield for picosecond laser target produces composite complex radiation environment

Abstract

The present application relates to a kind of complex shielding body for picosecond laser target generation complex complex radiation environment, belong to electromagnetic pulse shielding and protection material technical field.It includes from outside to inside sequentially arranged precipitation hardening stainless steel layer, first transparent glass layer, porous carbon load copper cobalt bimetallic shielding layer, second transparent glass layer, porous carbon load copper metal shielding layer and third transparent glass layer;Synergistic effect between layers, realize the shielding protection of complex electromagnetic radiation generated by picosecond laser and solid target, including the effective shielding absorption of charged particles such as electron, photon such as gamma ray and other particles.The complex shielding body has strong environmental adaptability, and can effectively shield the electromagnetic pulse generated by picosecond kilojoule level large laser device target chamber, and the complex shielding efficiency can reach more than 50%, which can be applied to device protection, laser protection and other fields.

Description

TECHNICAL FIELD

[0001] The application relates to a composite shield for a composite complex radiation environment generated by picosecond laser target shooting, and belongs to the technical field of electromagnetic pulse shielding and protection materials. BACKGROUND

[0002] With the rapid development of electronic technology, the functions and performance of electronic systems, weapon systems and the like are greatly improved, and at the same time, the impact of electromagnetic pulses in the above systems is also strengthened. The electromagnetic pulse intensity generated by picosecond laser is greater than that generated by nanosecond and femtosecond laser, and the radiation environment generated by the interaction of picosecond laser and solid targets is very complex, so an effective protection method for the complex radiation environment generated by picosecond laser target shooting is urgently needed. In addition, the distribution of the pores of the existing porous carbon-based wave-absorbing material is still reserved in the cross section of the carbon material, such as the article "Porous carbon fiber wave-absorbing composite material and its influencing factors"; or the porous carbon material cannot be formed into a filamentous structure, and the pores on the filament or between the filaments are used to meet the quarter wavelength absorption law as much as possible, such as the porous carbon wave-absorbing material synthesized in "Preparation of boron nitride-doped porous carbon composite material and study on its wave-absorbing performance". Therefore, a controllable synthesis method of porous carbon fiber is urgently needed. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a composite shield for a complex radiation environment generated by picosecond laser target shooting.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows.

[0005] A composite shield for a complex radiation environment generated by picosecond laser target shooting, comprising, from the outside to the inside, a precipitation hardened stainless steel layer, a first transparent glass layer, a porous carbon loaded copper-cobalt bimetal shielding layer, a second transparent glass layer, a porous carbon loaded copper metal shielding layer and a third transparent glass layer;

[0006] The porous carbon loaded copper-cobalt bimetal shielding layer is formed by mixing the porous carbon loaded copper-cobalt bimetal shielding material with hot melt paraffin and then coating it on the first transparent glass layer and the second transparent glass layer;

[0007] The porous carbon loaded copper metal shielding layer is formed by mixing the porous carbon loaded copper metal shielding layer material with hot melt paraffin and then coating it on the second transparent glass layer and the third transparent glass layer.

[0008] Preferably, the thickness ratio of the precipitated hardened stainless steel layer, the first transparent glass layer, the porous carbon loaded copper-cobalt bimetallic shielding layer, the second transparent glass layer, the porous carbon loaded copper metal shielding layer and the third transparent glass layer is 5-6: 1-2: 3-4: 1-2: 3-4: 1-2. More preferably, the thickness of the precipitated hardened stainless steel layer is 5-6 mm, the thickness of the first transparent glass layer, the second transparent glass layer and the third transparent glass layer is 1-2 mm respectively, and the thickness of the porous carbon loaded copper-cobalt bimetallic shielding layer and the porous carbon loaded copper metal shielding layer is 3-4 mm respectively.

[0009] Preferably, the material of the precipitated hardened stainless steel layer is 15-5PH type precipitated hardened stainless steel.

[0010] Preferably, the volume ratio of the porous carbon loaded copper-cobalt bimetallic shielding material to hot molten paraffin is 5: 5-6: 4.

[0011] Preferably, the porous carbon loaded copper-cobalt bimetallic shielding material is prepared by the following method, the method steps comprising:

[0012] (1) mixing polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate and deionized water, heating and dissolving, then adding polytetrafluoroethylene, stirring and mixing uniformly to obtain a spinning solution;

[0013] (2) electrospinning the spinning solution to obtain a polymer fiber;

[0014] (3) placing the polymer fiber in a muffle furnace, raising the temperature to 280±10℃ at a temperature raising rate of 2-3℃ / min, keeping the temperature for 2-3h, and then naturally cooling to obtain a pre-oxidized fiber;

[0015] (4) placing the pre-oxidized fiber in a tube furnace, first raising the temperature to 400-450℃ at a temperature raising rate of 2-3℃ / min, then raising the temperature to 500-550℃ at a temperature raising rate of 0.8-1.2℃ / min and keeping the temperature for 1-2h, and then raising the temperature to 700-800℃ at a temperature raising rate of 2-3℃ / min and keeping the temperature for 2-3h, and then naturally cooling to obtain a porous carbon loaded copper-cobalt bimetallic shielding material.

[0016] Preferably, in step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate and deionized water is 30-40: 3-5: 3-5: 200, and the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1: 1.8-2.2.

[0017] Preferably, in step (2), when electrospinning, the temperature is 40-50℃, the humidity is 40%-50%, the positive voltage is 20-25KV, the negative voltage is -2--5KV, the flow rate is 0.05-1mm / min, and the receiving distance is 20-25cm.

[0018] Preferably, the volume ratio of the porous carbon loaded copper metal shielding layer material to hot melt paraffin is 5:5 to 6:4.

[0019] Preferably, the porous carbon loaded copper metal shielding material is prepared by the following method, the method steps comprising:

[0020] (1) mixing polyvinyl alcohol, copper nitrate trihydrate and deionized water, heating and dissolving, then adding polytetrafluoroethylene, stirring and mixing uniformly to obtain a spinning solution;

[0021] (2) electrospinning the spinning solution to obtain a polymer fiber;

[0022] (3) placing the polymer fiber in a muffle furnace, raising the temperature to 280±10℃ at a temperature raising rate of 2-3℃ / min, keeping the temperature for 2-3h, and then naturally cooling to obtain a pre-oxidized fiber;

[0023] (4) placing the pre-oxidized fiber in a tube furnace, first raising the temperature to 400-450℃ at a temperature raising rate of 2-3℃ / min, then raising the temperature to 500-550℃ at a temperature raising rate of 0.8-1.2℃ / min and keeping the temperature for 1-2h, then raising the temperature to 700-800℃ at a temperature raising rate of 2-3℃ / min and keeping the temperature for 2-3h, and then naturally cooling to obtain a porous carbon loaded copper metal shielding material.

[0024] Preferably, in step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate and deionized water is 15-20:3-5:100; and the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1:1.8-2.2.

[0025] Preferably, in step (2), when electrospinning, the temperature is 40-50℃, the humidity is 40%-50%, the positive voltage is 20-25KV, the negative voltage is -2--5KV, the flow rate is 0.05-1mm / min, and the receiving distance is 20-25cm.

[0026] Beneficial effects

[0027] The application provides a composite shielding body for a complex radiation environment generated by picosecond laser target shooting.

[0028] The application provides a composite shielding body for a complex radiation environment generated by picosecond laser target shooting. The application provides a composite shielding body for a complex radiation environment generated by picosecond laser target shooting.

[0029] The application provides a composite shielding body for a complex radiation environment generated by picosecond laser target shooting. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Modeling diagram of the composite shield according to the present application.

[0031] Figure 2 Structure diagram of the composite shield according to the present application.

[0032] Figure 3 X-ray diffraction diagram of the porous carbon loaded copper metal shielding material in Example 1 of the present application.

[0033] Figure 4 Microscopic morphology diagram of the porous carbon loaded copper metal shielding material in Example 1 of the present application.

[0034] Figure 5 Microscopic morphology diagram of the porous carbon loaded copper metal shielding material in Comparative Example 1 of the present application.

[0035] Figure 6 X-ray diffraction diagram of the porous carbon loaded copper cobalt bimetal shielding material in Example 2 of the present application.

[0036] Figure 7 Microscopic morphology diagram of the porous carbon loaded copper cobalt bimetal shielding material in Example 2 of the present application.

[0037] Figure 8 Microscopic morphology diagram of the porous carbon loaded copper cobalt bimetal shielding material in Comparative Example 2 of the present application.

[0038] Figure 9 Time domain diagram of the electromagnetic pulse signal in the target chamber of the kilojoule level laser device in Example 3 of the present application.

[0039] Figure 10 Amplitude of the electromagnetic pulse signal inside and outside the 15-5ph precipitation hardened stainless steel shielding box in the target chamber of the kilojoule level laser device in Example 3 of the present application.

[0040] Figure 11 Amplitude of the electromagnetic pulse signal inside and outside the 15-5ph precipitation hardened stainless steel shielding box in the target chamber of the kilojoule level laser device in Example 3 of the present application.

[0041] Figure 12 Distribution relationship of the complex permittivity ε and the complex permeability μ of the porous carbon loaded copper metal shielding material in Example 3 of the present application in the 0.1-8GHz waveband.

[0042] Figure 13 Distribution relationship of the complex permittivity ε and the complex permeability μ of the porous carbon loaded copper cobalt bimetal shielding material in Example 3 of the present application in the 0.1-8GHz waveband. DETAILED DESCRIPTION

[0043] The present application will be further described in conjunction with specific embodiments.

[0044] As shown in Figures 1-2 A composite shield for a picosecond laser target produces a complex complex radiation environment, comprising a precipitation hardened stainless steel layer, a first transparent glass layer, a porous carbon loaded copper cobalt bimetallic shielding layer, a second transparent glass layer, a porous carbon loaded copper metal shielding layer and a third transparent glass layer arranged in turn from the outside to the inside;

[0045] The porous carbon loaded copper cobalt bimetallic shielding layer is formed by mixing the porous carbon loaded copper cobalt bimetallic shielding material with hot melting paraffin wax and then coating it on the first transparent glass layer and the second transparent glass layer;

[0046] The porous carbon loaded copper metal shielding layer is formed by mixing the porous carbon loaded copper metal shielding layer material with hot melting paraffin wax and then coating it on the second transparent glass layer and the third transparent glass layer.

[0047] In some embodiments, the thickness ratio of the precipitation hardened stainless steel layer, the first transparent glass layer, the porous carbon loaded copper cobalt bimetallic shielding layer, the second transparent glass layer, the porous carbon loaded copper metal shielding layer and the third transparent glass layer is 5-6:1-2:3-4:1-2:3-4:1-2.

[0048] In some embodiments, the thickness of the precipitation hardened stainless steel layer is 5-6mm, the thickness of the first transparent glass layer, the second transparent glass layer and the third transparent glass layer is 1-2mm respectively, and the thickness of the porous carbon loaded copper cobalt bimetallic shielding layer and the porous carbon loaded copper metal shielding layer is 3-4mm respectively.

[0049] In some embodiments, the precipitation hardened stainless steel layer is made of 15-5PH type precipitation hardened stainless steel.

[0050] In some embodiments, the volume ratio of the porous carbon loaded copper cobalt bimetallic shielding material and hot melting paraffin wax is 5:5-6:4.

[0051] In some embodiments, the porous carbon loaded copper cobalt bimetallic shielding material is prepared by the following method, the method steps comprising:

[0052] (1) Mix polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate and deionized water, heat and dissolve, then add polytetrafluoroethylene, stir and mix uniformly to obtain a spinning solution;

[0053] (2) Electrospinning the spinning solution to obtain a polymer fiber;

[0054] (3) Place the polymer fiber in a muffle furnace, heat at a rate of 2-3℃ / min to 280±10℃, keep warm for 2-3h, and then naturally cool to obtain a pre-oxidized fiber;

[0055] (4) placing the pre-oxidized fiber in a tube furnace under a protective gas atmosphere, first increasing to 400-450°C at a heating rate of 2-3°C / min, then increasing to 500-550°C at a heating rate of 0.8-1.2°C / min for 1-2h, and then increasing to 700-800°C at a heating rate of 2-3°C / min for 2-3h, and naturally cooling to obtain a porous carbon loaded copper metal shielding material.

[0056] In some embodiments, in step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate and deionized water is 30-40:3-5:3-5:200; the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1:1.8-2.2.

[0057] In some embodiments, in step (2), during electrospinning, the temperature is 40-50°C, the humidity is 40%-50%, the positive voltage is 20-25KV, the negative voltage is -2--5KV, the flow rate is 0.05-1mm / min, and the receiving distance is 20-25cm.

[0058] In some embodiments, the volume ratio of the porous carbon loaded copper metal shielding layer material to hot molten paraffin is 5:5-6:4.

[0059] In some embodiments, the porous carbon loaded copper metal shielding material is prepared by the following method, the method steps comprising:

[0060] (1) mixing polyvinyl alcohol, copper nitrate trihydrate and deionized water, heating and dissolving, then adding polytetrafluoroethylene, stirring and mixing uniformly to obtain a spinning solution;

[0061] (2) electrospinning the spinning solution to obtain a polymer fiber;

[0062] (3) placing the polymer fiber in a muffle furnace, increasing to 280±10°C at a heating rate of 2-3°C / min, and naturally cooling after holding for 2-3h to obtain a pre-oxidized fiber;

[0063] (4) placing the pre-oxidized fiber in a tube furnace under a protective gas atmosphere, first increasing to 400-450°C at a heating rate of 2-3°C / min, then increasing to 500-550°C at a heating rate of 0.8-1.2°C / min for 1-2h, and then increasing to 700-800°C at a heating rate of 2-3°C / min for 2-3h, and naturally cooling to obtain a porous carbon loaded copper metal shielding material.

[0064] In some embodiments, in step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate and deionized water is 15-20:3-5:100; the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1:1.8-2.2.

[0065] In some embodiments, in step (2), when electrospinning, the temperature is 40-50℃, the humidity is 40%-50%, the positive voltage is 20-25KV, the negative voltage is -2--5KV, the flow rate is 0.05-1mm / min, and the receiving distance is 20-25cm.

[0066] Example 1

[0067] In this embodiment, the copper nitrate trihydrate has a purity of 99.9% and a molecular weight of 241.6, and is purchased from Shanghai Aldrin Biochemical Technology Co., Ltd.; the carbon source is an organic compound polyvinyl alcohol (PVA), which is purchased from Shanghai Aldrin Biochemical Technology Co., Ltd.; and the pore-forming agent is an organic compound polytetrafluoroethylene dispersion liquid (PTFE), which is purchased from Shanghai Mayreel Chemical Technology Co., Ltd.

[0068] After mixing 1.5g of PVA and 0.3g of copper nitrate trihydrate, 10mL of deionized water is added, heated in a water bath at 90℃ and 500r / min for 180 minutes, and then 3g of PTFE is added after the stirring is completed and the temperature is lowered to room temperature. The above-mentioned mixed solution is stirred at room temperature for 12 hours to prepare a spinning solution. Then, a silk-like structure is constructed using an electrospinning mechanism of SS-2535H type purchased from Beijing Yongkangleye Science and Technology Development Co., Ltd. The spinning solution is loaded into a 10ml syringe, the distance between the spinning solution ejection point and the receiving drum is 22cm, a positive voltage of 22kV and a negative voltage of -2kV are applied, and electrospinning is carried out at a constant temperature of 40% humidity and 40℃ at a pushing speed of 0.06mm / min to obtain a polymer spinning fiber. The polymer spinning fiber is pre-oxidized in a KSL-1200X type muffle furnace purchased from Hefei Kejing Material Technology Co., Ltd., the heating rate is 2℃ / min, the final temperature is 280℃, and after two hours of heat preservation, the temperature is naturally lowered. After cooling, the above-mentioned material is placed in an OTF-1200X type tube furnace purchased from Hefei Kejing Material Technology Co., Ltd. for air sintering, argon gas is introduced, the temperature is raised to 400℃ at a rate of 2℃ / min from room temperature, then raised to 500℃ at a rate of 1℃ / min, and then kept at 500℃ for 1 hour, and then raised to 800℃ at a rate of 2℃ / min, and kept at 800℃ for 2 hours before naturally cooling down. After cooling, the porous carbon supported single-metal copper shielding material is obtained.

[0069] The X-ray diffraction results of the porous carbon supported single-metal copper shielding material are shown in Figure 3 The scanning electron microscope results are shown in Figure 4 ​

[0070] Comparative Example 1

[0071] In this comparative example, the sintering was directly raised to 800℃ at a heating rate of 2℃ / min, and then naturally cooled after holding for two hours. The rest was the same as Example 1, and a porous carbon supported single-metal copper shielding material was obtained.

[0072] The scanning electron microscope results of the porous carbon supported single-metal copper shielding material are shown in Figure 5 .

[0073] Example 2

[0074] In this example, the copper nitrate trihydrate was purchased from Shanghai Aldrin Biochemical Science and Technology Co., Ltd. with a purity of 99.9% and a molecular weight of 241.6; the cobalt nitrate hexahydrate was purchased from Shanghai Aldrin Biochemical Science and Technology Co., Ltd. with a purity of 99% and a molecular weight of 291.03; the carbon source was an organic compound polyvinyl alcohol (PVA) purchased from Shanghai Aldrin Biochemical Science and Technology Co., Ltd.; and the pore-forming agent was an organic compound polytetrafluoroethylene dispersion liquid (PTFE) purchased from Shanghai Mayreel Chemical Technology Co., Ltd.

[0075] After mixing 1.5g of PVA, 0.15g of copper nitrate trihydrate and 0.15g of cobalt nitrate hexahydrate, 10mL of deionized water was added, and the mixture was heated in a water bath at 90℃ and 500r / min for 180 minutes. After the stirring was completed and the temperature was lowered to room temperature, 3g of PTFE was added, and the above-mentioned mixed solution was stirred at room temperature for 12 hours to prepare a spinning solution. Subsequently, a silk-like structure was constructed using an SS-2535H type electrospinning mechanism purchased from Beijing Yongkangleye Science and Technology Development Co., Ltd., the spinning solution was loaded into a 10ml syringe, the distance between the spinning solution ejection point and the receiving drum was 22cm, a positive voltage of 22kV and a negative voltage of -2kV were applied, and electrospinning was performed at a constant temperature of 40℃ and a humidity of 40% at a pushing speed of 0.06mm / min to obtain a polymer spinning fiber. The polymer spinning fiber was pre-oxidized in a KSL-1200X type muffle furnace purchased from Hefei Kejing Material Technology Co., Ltd. at a heating rate of 2℃ / min and a final temperature of 280℃, and then naturally cooled after holding for two hours. After cooling, the above-mentioned material was placed in an OTF-1200X type tube furnace purchased from Hefei Kejing Material Technology Co., Ltd. for sintering with gas, argon gas was introduced, the temperature was raised to 400℃ at a heating rate of 2℃ / min, then raised to 500℃ at a heating rate of 1℃ / min, and then held at 500℃ for 1 hour, and then raised to 800℃ at a heating rate of 2℃ / min, and then naturally cooled after holding for two hours. After cooling, a porous carbon supported copper-cobalt bimetal shielding material was obtained.

[0076] The X-ray diffraction results of the porous carbon supported copper-cobalt bimetal shielding material are shown in Figure 6The scanning electron microscope results are shown in FIG. 1. Figure 7

[0077] Comparative Example 2

[0078] In this comparative example, during sintering, the temperature was directly raised to 800°C at a rate of 2°C / min, and then naturally cooled after holding for two hours. The rest was the same as in Example 1, and a porous carbon-supported copper-cobalt bimetallic shielding material was obtained.

[0079] The scanning electron microscope results of the porous carbon-supported copper-cobalt bimetallic shielding material are shown in FIG. 2. Figure 8

[0080] Comparative Example 2 Figures 4-5 , Figures 7-8 From the results of Comparative Example 1, it can be seen that in the preparation process of the porous carbon-supported single-metal copper shielding material and the porous carbon-supported copper-cobalt bimetallic shielding material, the optimization of the microstructure and performance of the material is one of the key steps of controlling the heating mode. In Comparative Example 1, before the heating curve is controlled, the observed material morphology exhibits obvious shortcomings. Specifically, the size of the metal particles is abnormally large, which not only increases the surface roughness of the material, but also adversely affects the overall performance of the material such as electrical conductivity and mechanical strength. At the same time, the embedding mode of these large-sized metal particles in the filamentous carbon structure is also not ideal, resulting in a significant connection phenomenon of the holes on the filamentous structure. This excessive connection not only weakens the integrity and stability of the filamentous structure, but also may affect the key characteristics such as permeability of the material, thereby to some extent destroying its original design intention and functional advantages.

[0081] In Example 1, by introducing a more gentle heating rate, setting a suitable temperature platform, and precise temperature control, the phase transition and crystal growth behavior during the synthesis of the material are precisely controlled. This improvement measure brings significant changes: the size of the metal particles is significantly refined, their distribution becomes more uniform, and they are more closely embedded in the filamentous carbon structure, reducing the proportion of exposure, which not only enhances the interaction force between the metal and the carbon matrix, but also promotes the electron transfer and energy exchange between the two, bringing the material better comprehensive performance.

[0082] In addition, the optimized heating mode also causes positive changes in the distribution of holes on the filamentous carbon structure. The number and size of the holes are reasonably controlled, retaining enough pore space to maintain the high specific surface area and good permeability of the material, while avoiding excessive adhesion between the holes, ensuring the uniformity and independence of the hole distribution. The optimization of this hole structure can improve the mechanical properties and thermal stability of the material to some extent.

[0083] ​​In summary, by scientific regulation of the heating mode, the problems of oversize metal particle size and connected pores are successfully solved, and the combination between the filamentous carbon structure and the metal is more closely and the pore structure is optimized.

[0084] Example 3

[0085] A composite shield for a picosecond laser target generates a composite complex radiation environment, comprising, from the outside to the inside, a precipitation hardened stainless steel layer, a first transparent glass layer, a porous carbon loaded copper cobalt bimetallic shielding layer, a second transparent glass layer, a porous carbon loaded copper metal shielding layer and a third transparent glass layer;

[0086] The porous carbon loaded copper cobalt bimetallic shielding layer is formed by mixing the porous carbon loaded copper cobalt bimetallic shielding material prepared in Example 2 with hot melt paraffin and then coating on the first transparent glass layer and the second transparent glass layer; the volume ratio of the porous carbon loaded copper cobalt bimetallic shielding material to the hot melt paraffin is 6:4.

[0087] The porous carbon loaded copper metal shielding layer is formed by mixing the porous carbon loaded copper metal shielding layer material prepared in Example 1 with hot melt paraffin and then coating on the second transparent glass layer and the third transparent glass layer; the volume ratio of the porous carbon loaded copper metal shielding layer material to the hot melt paraffin is 6:4.

[0088] The thickness of the precipitation hardened stainless steel layer is 5mm, the thickness of the first transparent glass layer, the second transparent glass layer and the third transparent glass layer is 1mm respectively, and the thickness of the porous carbon loaded copper cobalt bimetallic shielding layer and the porous carbon loaded copper metal shielding layer is 3mm respectively.

[0089] The material of the precipitation hardened stainless steel layer is 15-5PH type precipitation hardened stainless steel.

[0090] The precipitation hardened stainless steel, the porous carbon loaded copper cobalt bimetallic shielding material and the porous carbon loaded copper metal shielding layer material are tested respectively.

[0091] The 15-5ph type precipitation hardened stainless steel shielding box is placed in the picosecond laser target chamber, and the signal receiving antennas are connected inside and outside the shielding box for comparison. Among them, the antennas inside and outside the shielding box are placed in the same direction in the target chamber for comparison. After the electromagnetic pulse is generated, the magnetic field antenna can be connected to a suitable range oscilloscope through a cable and an attenuator for collection. Figure 9The laser parameters for obtaining the electromagnetic pulse are ps-60.6J, 812fs; the solid target interacting with the picosecond laser is a CH filament target with a thickness of 20μm. An antenna is placed in a shielding box at a distance of 80cm behind the target, and a bare antenna is placed at the same distance and orientation. After the electromagnetic pulse signal generated by the interaction of the picosecond laser and the solid target, the results are shown in Figure 10 , the electromagnetic pulse intensity detected by the bare antenna is 1173kV / m, and the electromagnetic pulse amplitude detected by the antenna in the 15-5ph type precipitation hardened stainless steel shielding box is 431kV / m. The electromagnetic pulse signal intensity is reduced by more than half, and the attenuation efficiency is about 63.6%, so the shielding effect is more significant.

[0092] To avoid accidental errors in the experiment, multiple experimental tests are conducted in this application, and the results are shown in Figure 11 , in three experiments, the antenna detection results in the shielding box have obvious attenuation, and the attenuation efficiency is more than 50% compared with the antenna without shielding box.

[0093] To test the electromagnetic pulse shielding performance of the porous carbon loaded single metal copper shielding material and the porous carbon loaded copper-cobalt bimetal shielding material, the two materials are mixed and melted according to a volume ratio of 6:4 with hot melt paraffin, and then pressed into a ring. As shown in Figure 12 , the porous carbon loaded single metal copper shielding material is pressed into a hollow cylindrical shielding body with an inner diameter of 3mm, an outer diameter of 7mm, and a height of 3.15mm. The complex permittivity and complex permeability distribution in the frequency range of 0.1-8GHz, and the dielectric loss and magnetic loss of the shielding material can be measured by the ratio of the imaginary part to the real part of the complex permittivity and the ratio of the imaginary part to the real part of the complex permeability. Figure 12 The measurement data show that the dielectric loss of the material is better than the magnetic loss and the difference is large, so the impedance matching needs to be adjusted, and therefore multiple materials are used for progressive shielding.

[0094] As shown in Figure 13 , in the test frequency range, the porous carbon loaded copper-cobalt bimetal shielding material and hot melt paraffin are mixed and melted according to a volume ratio of 6:4, and then pressed into a hollow cylindrical shielding body with an inner diameter of 3mm, an outer diameter of 7mm, and a height of 2.72mm. Since the magnetic metal element cobalt is added to the wave-absorbing material, the magnetic loss capacity of the porous carbon loaded copper-cobalt bimetal shielding material is greatly improved, and the dielectric loss changes little, so the porous carbon loaded copper-cobalt bimetal shielding material has better impedance matching.

[0095] The selection and arrangement of each layer of material in the shielding system described in this embodiment aims to provide multiple barriers to minimize the penetration and interference of electromagnetic waves. The following is a detailed analysis of the interaction and coupling relationship between each layer:

[0096] Outer layer: 15-5PH type precipitation hardened stainless steel shielding box: 15-5PH alloy is an ideal material for the outer shielding box due to its high strength (tensile strength up to 1700MPa or more, yield strength up to 1400MPa or more), high corrosion resistance (especially in high temperature and humid environment) and good processing performance. It can withstand physical and chemical impact from the external environment and protect the internal shielding layer from damage. Secondly, it contains high atomic number atoms that can effectively absorb photons and reduce the impact of charged particles through grounding, forming a preliminary electromagnetic isolation and reducing the direct impact of external electromagnetic fields on the inner layer material.

[0097] Second layer: transparent glass, which has good transparency to ensure that light transmission is not affected; secondly, as an intermediate layer, it provides structural support for the entire shielding system and can serve as a carrier for shielding materials, allowing them to be better fixed in place; finally, transparent glass itself does not have electromagnetic shielding function, but as a non-conductive material, it can reduce the reflection of electromagnetic waves and avoid the formation of unnecessary standing waves or reflected waves inside the shielding system.

[0098] Third layer: 3mm thick shielding material made of porous carbon loaded copper-cobalt bimetal shielding material mixed with hot melt paraffin. Porous carbon material has excellent electrical conductivity and porous structure, which can effectively absorb and scatter electromagnetic waves. The addition of copper and cobalt bimetal further enhances its electrical conductivity and electromagnetic shielding performance, effectively regulates the relationship between complex permittivity and complex permeability, and improves impedance matching, allowing electromagnetic waves to interact with the shielding material with less reflection, thereby significantly reducing the impact of electromagnetic fields on the interior. At the same time, hot melt paraffin as a base material, by adjusting the proportion of its use with porous carbon loaded copper-cobalt bimetal shielding material, can effectively adjust the absorption and reflection ability of the shielding material. It forms an effective electromagnetic shielding layer between the inner transparent glass and the outer stainless steel shielding box, reducing the possibility of electromagnetic waves penetrating further into the inner layer. Together with the outer stainless steel shielding box, it forms a double electromagnetic barrier, improving the overall shielding effect.

[0099] Fourth layer: transparent glass, which has the same function as the second layer, connecting the inner and outer shielding materials to ensure the integrity and stability of the overall structure.

[0100] The fifth layer: the 3mm thick shielding material prepared by mixing the porous carbon loaded copper single metal shielding material and hot melt paraffin, similar to the third layer, but using single metal copper loading makes the material only have good electrical conductivity, although it cannot completely reduce electromagnetic wave reflection as the third layer, but the reflected electromagnetic wave will still act on the previous several layers of material. Therefore, this layer reduces the influence of electromagnetic wave on the internal shielding system as much as possible.

[0101] The sixth layer: transparent glass, the role of this layer is consistent with the role of the above two layers of transparent glass, that is, it plays a fixed supporting role, and forms the final electromagnetic shielding layer with the fifth layer, ensuring that the internal equipment or space is immune to external electromagnetic interference.

[0102] In summary, the present application provides a shielding method for the complex and complex radiation environment generated by picosecond laser targeting, which uses 15-5ph type precipitation hardening stainless steel as the shell of the absorption system to protect the internal porous carbon loaded single metal copper shielding material and the porous carbon loaded copper and cobalt double metal shielding material, so that the method has stronger environmental adaptability, and can effectively shield the electromagnetic pulse generated by the picosecond kilojoule level large laser device target chamber, and the composite shielding efficiency can reach more than 50%, which can be applied to device protection, laser protection and other fields. It can be further used with the grounding system or electromagnetic interference suppressor to improve the overall electromagnetic shielding effect and anti-interference ability.

[0103] In summary, the present application includes but is not limited to the above embodiments, any equivalent replacement or partial improvement made under the spirit and principles of the present application will be considered within the scope of protection of the present application.

Claims

1. A composite shield against picosecond laser target generation of a complex complex radiation environment, characterized in that: The layer comprises, from outside to inside, a precipitation hardened stainless steel layer, a first transparent glass layer, a porous carbon loaded copper cobalt bimetal shielding layer, a second transparent glass layer, a porous carbon loaded copper metal shielding layer, and a third transparent glass layer. The porous carbon loaded copper cobalt bimetal shielding layer is formed by mixing the porous carbon loaded copper cobalt bimetal shielding material with hot melt paraffin and then coating the mixture on the first transparent glass layer and the second transparent glass layer. The porous carbon loaded copper metal shielding layer is formed by mixing the porous carbon loaded copper metal shielding layer material with hot melt paraffin and then coating the mixture on the second transparent glass layer and the third transparent glass layer. The thickness ratio of the precipitation hardened stainless steel layer, the first transparent glass layer, the porous carbon loaded copper cobalt bimetal shielding layer, the second transparent glass layer, the porous carbon loaded copper metal shielding layer, and the third transparent glass layer is 5-6:1-2:3-4:1-2:3-4:1-2.

2. A composite shield against picosecond laser target produced complex complex radiation environment according to claim 1, characterized in that: The thickness of the precipitation hardened stainless steel layer is 5-6 mm, the thickness of the first transparent glass layer, the second transparent glass layer, and the third transparent glass layer is 1-2 mm, and the thickness of the porous carbon loaded copper cobalt bimetal shielding layer and the porous carbon loaded copper metal shielding layer is 3-4 mm.

3. A composite shield against picosecond laser target produced complex complex radiation environment according to claim 1, characterized in that: The precipitation hardened stainless steel layer is made of 15-5PH type precipitation hardened stainless steel.

4. A composite shield for picosecond laser target complex complex radiation environment according to claim 1, characterized in that: The volume ratio of the porous carbon loaded copper cobalt bimetal shielding material to hot melt paraffin is 5:5-6:

4.

5. A composite shield for picosecond laser target complex complex radiation environment according to claim 1, characterized in that: The porous carbon loaded copper cobalt bimetal shielding material is prepared by the following method, and the method steps include: (1) Mix polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate, and deionized water, heat and dissolve, then add polytetrafluoroethylene, stir and mix uniformly to obtain a spinning solution; (2) Electrospinning the spinning solution to obtain a polymer fiber; (3) Place the polymer fiber in a muffle furnace, heat at a rate of 2-3℃ / min to 280±10℃, keep for 2-3h, and then naturally cool to obtain a pre-oxidized fiber; (4) Place the pre-oxidized fiber in a tube furnace, first heat at a rate of 2-3℃ / min to 400-450℃, then heat at a rate of 0.8-1.2℃ / min to 500-550℃ for 1-2h, and then heat at a rate of 2-3℃ / min to 700-800℃ for 2-3h, and then naturally cool to obtain a porous carbon loaded copper cobalt bimetal shielding material.

6. A composite shield for picosecond laser target complex complex radiation environment according to claim 5, characterized in that: In step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate, cobalt nitrate hexahydrate, and deionized water is 30-40:3-5:3-5:200; the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1:1.8-2.

2. In step (2), during electrospinning, the temperature is 40-50℃, the humidity is 40%-50%, the positive voltage is 20-25KV, the negative voltage is -2--5KV, the flow rate is 0.05-1mm / min, and the receiving distance is 20-25cm.

7. A composite shield for picosecond laser target complex complex radiation environment according to claim 1, characterized in that: The volume ratio of the porous carbon loaded copper metal shielding layer material to hot melt paraffin is 5:5-6:

4.

8. A composite shield for picosecond laser target complex complex radiation environment according to claim 1, characterized in that: The porous carbon loaded copper metal shielding material is prepared by the following method, and the method steps include: (1) polyvinyl alcohol, copper nitrate trihydrate and deionized water are mixed, heated and dissolved, then polytetrafluoroethylene is added, stirred and mixed uniformly to obtain a spinning solution; (2) electrospinning the spinning solution to obtain a polymer fiber; (3) the polymer fiber is placed in a muffle furnace, the temperature is raised to 280±10℃ at a rate of 2~3℃ / min, and then the temperature is kept for 2~3h, and then the fiber is naturally cooled to obtain a pre-oxidized fiber; (4) the pre-oxidized fiber is placed in a tube furnace, and under the protection of a gas atmosphere, the temperature is first raised to 400~450℃ at a rate of 2~3℃ / min, then the temperature is raised to 500~550℃ at a rate of 0.8~1.2℃ / min for 1~2h, then the temperature is raised to 700~800℃ at a rate of 2~3℃ / min for 2~3h, and then the fiber is naturally cooled to obtain a porous carbon loaded copper metal shielding material.

9. A composite shield for picosecond laser target produced complex complex radiation environment according to claim 8, characterized in that: In step (1), the mass ratio of polyvinyl alcohol, copper nitrate trihydrate and deionized water is 15~20:3~5:100; the mass ratio of polyvinyl alcohol to polytetrafluoroethylene is 1:1.8~2.2; In step (2), when electrospinning, the temperature is 40~50℃, the humidity is 40%~50%, the positive voltage is 20~25KV, the negative voltage is -2~-5KV, the flow rate is 0.05~1mm / min, and the receiving distance is 20~25cm.

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