Broad-spectrum response radiation-resistant rod-tube assemblies, their fabrication methods and applications

Abstract

This invention proposes a broadband-response radiation-resistant rod-tube assembly, its preparation method, and its applications. It includes a core rod and a tubing; the tubing is fitted over the core rod; the core rod glass has a transmittance of ≥65% in the 330–2000 nm spectrum at 100 mm depth; and a transmittance attenuation rate of ≤3% at 350 nm after 500 h of irradiation at 6.4 kGy; the tubing glass has a transmittance of ≥75% in the 330–2000 nm spectrum at 100 mm depth; and a transmittance attenuation rate of ≤3% at 350 nm after 500 h of irradiation at 6.4 kGy; the difference in thermal expansion coefficients between the core and the tubing is 1–10 × 10⁻⁶. ‑7 / ℃; the core-shell softening temperature difference is 10~25℃; the core-shell refractive index difference is >0.3; the core and shell glass remain chemically stable at 810℃. The technical problem to be solved is how to prepare a broadband-response radiation-resistant rod-tube assembly with good compatibility between the core rod and the tube, so that it can be used in the fabrication of fiber optic imaging arrays, improve the broadband-response radiation resistance of fiber optic imaging arrays, and meet the requirements of long-distance detection and long service life in radiation-irradiated environments such as aerospace.

Description

Technical Field

[0001] This invention relates to the field of optical fiber manufacturing technology, and in particular to a broadband spectral response radiation-resistant rod-tube assembly, its preparation method, and its application. Background Technology

[0002] Fiber optic image arrays are made of tens of millions of micron-sized fiber filaments tightly and regularly arranged and fused together. They can transmit images with high fidelity and have the characteristics of zero optical thickness, large numerical aperture, high resolution, and strong light-gathering ability. They include optical fiber panels, fiber optic image inverters, fiber optic cones, fiber optic image bundles, etc. They can be used as windows, optical coupling and display materials for optoelectronic detection devices such as micro-light image intensifiers, photomultiplier tubes, X-ray image intensifiers, star sensors, and high-end radiation medical equipment. They are high-tech cutting-edge products in the optoelectronic industry.

[0003] Fiber optic image transmission arrays utilize high-refractive-index core glass and low-refractive-index tubular glass tubes, combining the core and tubular components to draw monofilaments for arrangement. Absorbing glass is drawn into filaments and inserted into the arranged monofilaments; the absorbing glass primarily absorbs stray light. These are then bundled into a composite rod, drawn, arranged, and hot-melted into blank sections, followed by precision machining. Primarily used for high-definition image transmission, this system solves the problems of low field image resolution and poor clarity, thus improving imaging clarity.

[0004] Currently, fiber optic imaging arrays are used for long-distance detection in environments such as space where radiation is emitted. These arrays need to have a wide spectral transmittance to achieve a longer detection distance, while also being able to withstand radiation. It is difficult to satisfy both requirements simultaneously. Core glass and tubular glass are core components of fiber optic imaging arrays, and their quality and performance significantly impact the transmission performance. However, current technology lacks core glass that simultaneously meets the requirements of broad spectral response, radiation resistance, and high refractive index. Tubular glass primarily functions to form a total reflection layer at the core-skin interface. Due to its smaller size within the fiber optic panel, it is more prone to defects during fabrication, thus requiring superior resistance to radiation and ultraviolet transmission compared to core glass. Similarly, current technology lacks tubular glass that simultaneously meets the requirements of broad spectral response, radiation resistance, and low refractive index. Assembling core glass and tubular glass into a rod-tube assembly for fiber optic imaging arrays requires over 20 precision manufacturing processes, making the performance matching of the core glass and tubular glass crucial. However, current technology lacks reports on broad spectral response, radiation-resistant rod-tube assemblies. Summary of the Invention

[0005] The main objective of this invention is to provide a wide-spectrum response radiation-resistant rod-tube assembly, its preparation method, and its application. The technical problem to be solved is how to prepare a wide-spectrum response radiation-resistant rod-tube assembly with good compatibility between the core rod and the tubing, so that it can be used in the preparation of fiber optic imaging arrays, improve the wide-spectrum response radiation resistance of fiber optic imaging arrays, meet the requirements of long-distance detection and long service life in radiation environments such as aerospace, and thus be more suitable for practical use.

[0006] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a broadband-response radiation-resistant rod-tube assembly includes a core rod and a tubing; the tubing is sleeved on the outside of the core rod; the glass of the core rod, with a thickness of 100 mm, has a spectral transmittance ≥65% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%; the glass of the tubing, with a thickness of 100 mm, has a spectral transmittance ≥75% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%; wherein, the difference between the thermal expansion coefficient of the core rod glass and the thermal expansion coefficient of the tubing glass is 1 × 10⁻⁶. -7 / ℃~10×10 -7 / ℃; the difference between the softening temperature of the mandrel glass and the softening temperature of the tubular glass is 10~25℃; the difference between the refractive index of the mandrel glass and the refractive index of the tubular glass is >0.3; both the mandrel glass and the tubular glass remain chemically stable at 810℃.

[0007] The objective of this invention and the technical problem it solves are achieved through the following technical solution. A method for preparing a broadband-response radiation-resistant rod-tube assembly according to this invention includes the following steps:

[0008] S21 raw material metering, mixing, to obtain mandrel mixture and tubing mixture;

[0009] S22 melts the mandrel mixture and the tubing mixture, clarifies and stirs them, discharges the materials, casts them into shape, and anneals them to obtain a mandrel or tubing; the glass of the mandrel, with a thickness of 100 mm, has a spectral transmittance ≥65% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%; the glass of the tubing, with a thickness of 100 mm, has a spectral transmittance ≥75% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%.

[0010] S23 The tubing is fitted over the outside of the mandrel to obtain a mandrel-tube assembly; wherein the difference between the thermal expansion coefficient of the mandrel glass and the thermal expansion coefficient of the tubing glass is 1×10⁻⁶. -7 / ℃~10×10 -7 / ℃; the difference between the softening temperature of the mandrel glass and the softening temperature of the tubular glass is 10~25℃; the difference between the refractive index of the mandrel glass and the refractive index of the tubular glass is >0.3; both the mandrel glass and the tubular glass remain chemically stable at 810℃.

[0011] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0012] Preferably, in the aforementioned preparation method, the mandrel mixture, by mass percentage, comprises: 10-15% silica sand, 20-30% boric acid, 19.5-30% lanthanum oxide, 1.1-10% zinc oxide, 1.1-10% niobium oxide, 10.1-20% barium carbonate, 0-3% hafnium oxide, 5.1-10% tantalum oxide, 1.1-7% yttrium oxide, 0-5% strontium carbonate, 0.5-7% aluminum oxide, 0-5% sodium carbonate, and 0.05-2% cerium oxide; the tubing mixture comprises: 60-75% silica sand, 1.5-15% boric acid, 1-5% aluminum oxide, 1-10% sodium carbonate, and 1% potassium hydrofluoric acid. -8%, calcium fluoride 1-8%, basic magnesium carbonate 0-5%, lithium carbonate 0-8%, zinc oxide 0-5%, cerium oxide 0-2%; the total content of impurities Fe, Cu and Mn in the mandrel mixture and tubing mixture is ≤3ppm; the total content of impurities Nd, Pr, U, Er, Eu, Tb and Dy is ≤2ppm; the equipment for preparing and melting the mandrel mixture is made of non-metallic alkali-resistant material; the equipment for preparing and melting the tubing mixture is made of non-metallic material; oxygen is introduced into the glass melt during the melting and clarifying stirring steps; the melting furnace for melting and clarifying is made of refractory material with a heavy metal content ≤5ppm.

[0013] Preferably, in the aforementioned preparation method, the container for melting the mandrel mixture is a magnesium oxide crucible; the container for melting the tubing mixture is a quartz crucible, and the surface of the crucible is coated with a silicon oxide coating.

[0014] Preferably, in the aforementioned preparation method, the refractory material is an erosion-resistant and high-temperature resistant material with a temperature resistance ≥1700℃.

[0015] Preferably, in the aforementioned preparation method, the melting furnace for melting the mandrel mixture is dedicated to the preparation of the mandrel glass; or, the melting furnace for melting the tubing mixture is dedicated to the preparation of the tubing glass.

[0016] Preferably, in the aforementioned preparation method, the mixture is melted by adding the mixture into a container in 3-5 portions, with each portion spaced 0.5-2 hours apart.

[0017] Preferably, in the aforementioned preparation method, the melting temperature of the mandrel mixture is 1350-1400℃; the clarification and stirring temperature is 1460-1530℃, and the clarification and stirring time is 1-2 hours; the discharge temperature is 1300-1350℃; and the annealing temperature is 550-600℃, with an annealing time of 2-4 hours; or, the melting temperature of the tubing mixture is 1350-1400℃; the clarification and stirring temperature is 1460-1530℃, and the clarification and stirring time is 1-2 hours; the discharge temperature is 1300-1350℃; and the annealing temperature is 550-600℃, with an annealing time of 2-4 hours.

[0018] Preferably, in the aforementioned preparation method, when the mandrel is prepared, the flow rate of oxygen introduced into the molten glass is 0.1–0.3 mol / L / min; or, when the tubing is prepared, the flow rate of oxygen introduced into the molten glass is 0.04–0.18 mol / L / min.

[0019] The objective of this invention and the technical problem it solves are achieved by the following technical solution: The application of the broadband response radiation-resistant rod-tube assembly described above in the fabrication of broadband response radiation-resistant fiber optic imaging arrays, as proposed in this invention.

[0020] By employing the above technical solutions, the broadband response radiation-resistant rod-tube assembly, its preparation method, and its application proposed in this invention have at least the following advantages:

[0021] This invention proposes a broadband-response radiation-resistant rod-tube assembly, its preparation method, and its application. The assembly is formed by fabricating a broadband-response radiation-resistant core rod glass into a core rod and a broadband-response radiation-resistant tubing glass into a tubing, and then fitting the tubing over the core rod to form the rod-tube assembly. Through performance matching design between the core rod glass and the tubing glass, the rod-tube assembly exhibits good processability. Specifically, this invention, through matching the thermal expansion coefficients of the tubing and core rod, ensures that the thermal expansion coefficients of the core rod glass and the tubing glass are similar. This prevents optical fiber breakage due to mismatched thermal expansion coefficients during heating or cooling, and allows the tubing glass to better adhere to the core glass during subsequent fiber drawing and heating. Furthermore, during the drawing and cooling process, the sheath layer generates compressive stress, improving the strength of the optical fiber and ensuring compressive stress is generated during the drawing process, thus enhancing the strength of the optical fiber filament. Finally, through matching the softening temperatures of the tubing and core rod, this invention ensures that the core and sheath maintain their optimal properties during subsequent fiber drawing. The roundness of the glass allows the outer sheath to soften and bond during the pressing process, while the core material maintains its circular structure. This prevents light leakage caused by the core deformation failing to meet the total internal reflection condition. This invention, through a chemical property compatibility design between the sheath and the core rod, ensures good chemical compatibility between the core rod glass and the sheath glass near their respective temperature limits. The maximum process temperature of the rod-tube assembly designed in this invention is approximately 810℃ in subsequent fiber optic board fabrication. By limiting the chemical stability of both the core rod glass and the sheath glass at 810℃ (meaning that neither glass undergoes penetration, crystallization, or phase separation after 5 hours at 810℃), this invention effectively solves the problem of reduced transmittance caused by incomplete core-skin interfaces due to interpenetration, crystallization, or phase separation during the process. Furthermore, by limiting the refractive index difference between the core rod glass and the sheath glass to >0.3 through a design that matches the optical properties of the sheath and the core rod, this invention effectively improves the luminous flux N of the fiber optic imaging array. AThis improves the transmission efficiency of the fiber optic image transmission array, reduces the loss of images or signals during transmission, and thus improves the overall transmission quality of the fiber optic image transmission array. As can be seen from the above, in the technical solution of the present invention, by controlling the core rod glass to have a spectral transmittance ≥65% in the wavelength range of 330-2000nm at a thickness of 100mm, and a transmittance attenuation rate ≤3% at 350nm after irradiation at a dose of 6.4kGy for 500h, and controlling the tubing glass to have a spectral transmittance ≥75% in the wavelength range of 330-2000nm at a thickness of 100mm, and a transmittance attenuation rate ≤3% at 350nm after irradiation at a dose of 6.4kGy for 500h, it possesses good broadband spectral response and radiation resistance. Furthermore, through optimal matching of the core rod glass and the tubing glass, a rod-tube assembly with excellent comprehensive performance is prepared, making it easy to process in subsequent fiber optic imaging element fabrication, improving the broadband spectral response and radiation resistance of the fiber optic imaging array, and meeting the requirements for long-distance detection and long service life in radiation-irradiated environments such as aerospace.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0023] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a broadband-response radiation-resistant rod-tube assembly, its preparation method, and its specific implementation, structure, features, and effects according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0024] This invention proposes a broadband-response radiation-resistant rod-tube assembly, comprising a core rod and a tubing, with the tubing sleeved on the outside of the core rod. This rod-tube assembly design is a conventional configuration in the art. However, in this invention, both the core rod glass and the tubing glass are glass with broadband spectral response and radiation resistance. Specifically, the core rod glass, at a thickness of 100 mm, has a spectral transmittance ≥65% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%. Similarly, the tubing glass, at a thickness of 100 mm, has a spectral transmittance ≥75% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreases by ≤3%. In other words, both the core rod glass and the tubing glass exhibit superior radiation resistance, with the tubing glass having a higher transmittance than the core rod glass.

[0025] When combining two types of glass to form a core-tube assembly, the performance matching of the two glass types is crucial. First, poor matching can lead to an uneven fiber interface. When light propagates across these uneven interfaces, scattering occurs, resulting in signal loss and reducing the light-gathering capability of the fiber imaging array. Second, if the thermal expansion coefficients of the core and tube glass do not match, the core glass will be subjected to excessive compressive or tensile stress during heat treatment, reducing the strength of the optical fiber and damaging the roundness and structure of the fiber filament. Third, if the softening temperatures of the core and tube glass do not match, core deformation will occur during the pressing process, failing to meet the total internal reflection condition and causing light leakage. Fourth, if the viscosities of the core and tube glass do not match, inconsistent softening degrees during fiber drawing will hinder fiber production. Fifth, poor chemical compatibility between the core and tube glass can lead to interpenetration, crystallization, or phase separation during the fabrication process, resulting in an incomplete core-skin interface and reduced transmittance. Therefore, in addition to ensuring the high refractive index of the mandrel glass and the low refractive index of the tubular glass, the performance matching of the two types of glass is also crucial.

[0026] This invention limits the difference between the thermal expansion coefficient of the mandrel glass and the thermal expansion coefficient of the tubing glass to 1×10. -7 / ℃~10×10 -7 / ℃; By designing the performance matching between the core glass and the tubing glass, the thermal expansion coefficients of the core glass and the tubing glass are made similar. On the one hand, this prevents optical fiber breakage due to mismatched thermal expansion coefficients during heating or cooling. On the other hand, during the subsequent fiber drawing and heating process, the tubing glass can better adhere to the core glass. During the drawing and cooling process, the sheath layer can also generate a certain compressive stress, improving the strength of the optical fiber and ensuring that compressive stress can be formed during the drawing process, thus enhancing the strength of the optical fiber filament. This invention limits the softening temperature difference between the core glass and the tubing glass to 10-25℃, ensuring that the core and sheath glass are compatible during the subsequent drawing process. The sphericity of the glass allows the outer layer to soften and bond during the pressing process, while the core material maintains its circular structure. This prevents light leakage caused by core deformation failing to meet the total internal reflection condition. The invention ensures that both the core rod glass and the outer tube glass remain chemically stable at 810°C, meaning that neither glass undergoes penetration, crystallization, or phase separation after 5 hours at 810°C. This effectively solves the problem of reduced transmittance caused by incomplete core-outer interface due to interpenetration, crystallization, or phase separation between the glass layers during the process. Furthermore, by limiting the difference between the refractive index of the core rod glass and the refractive index of the outer tube glass to >0.3, the invention effectively increases the optical flux N of the fiber optic imaging array. AThis improves the transmission efficiency of the fiber optic image transmission array, reduces the loss of images or signals during transmission, and thus improves the overall transmission quality of the fiber optic image transmission array.

[0027] By defining the above-mentioned technical solution, this invention can obtain a rod-tube assembly with a wide spectral response and radiation resistance, which makes it easy to process in subsequent fiber optic imaging element fabrication, improves the wide spectral response and radiation resistance performance of fiber optic imaging arrays, and meets the requirements of long-distance detection and long service life in radiation environments such as aerospace.

[0028] This invention also proposes a method for preparing a broadband-response radiation-resistant rod-tube assembly, which includes the following steps: First, preparing a mandrel and a tubing. Specifically, this includes: metering and mixing raw materials to obtain a mandrel mixture and a tubing mixture; melting the mandrel mixture and the tubing mixture separately, clarifying and stirring, discharging, casting, and annealing to obtain a mandrel or tubing. Detailed explanation follows:

[0029] In some specific embodiments of the present invention, the mandrel mixture, by mass percentage, comprises: 10-15% quartz sand, 20-30% boric acid, 19.5-30% lanthanum oxide, 1.1-10% zinc oxide, 1.1-10% niobium oxide, 10.1-20% barium carbonate, 0-3% hafnium oxide, 5.1-10% tantalum oxide, 1.1-7% yttrium oxide, 0-5% strontium carbonate, 0.5-7% aluminum oxide, 0-5% sodium carbonate, and 0.05-2% cerium oxide, wherein the total content of impurities Fe, Cu, and Mn is ≤3ppm; and the total content of impurities Nd, Pr, U, Er, Eu, Tb, and Dy is ≤2ppm. The mandrel mixture is melted, clarified and stirred, shaped and annealed to obtain the mandrel; all components in the mandrel exist in the form of oxides, that is, it includes SiO2, B2O3, La2O3, ZnO, Nb2O5, BaO, HfO2, Ta2O5, Y2O3, SrO, Al2O3, Na2O and CeO2.

[0030] In the aforementioned mandrel glass, SiO2 is introduced in the form of quartz sand and forms the main body of the glass skeleton, playing a major role in the glass skeleton. The weight percentage of quartz sand raw material in the mandrel glass is 10-15%. When the quartz sand raw material content is below 10%, it is difficult to obtain glass with a high refractive index, and it also reduces the chemical stability of the glass; while when the quartz sand raw material content is above 15%, the high-temperature viscosity of the glass increases, resulting in excessively high glass melting temperature, and the coefficient of thermal expansion of the glass also decreases.

[0031] B₂O₃, introduced in the form of boric acid, is a glass-forming oxide and a component of the glass framework. It also acts as a flux to reduce the viscosity of the glass melt. Boron-oxygen trigonal [BO₃] and boron-oxygen tetrahedron [BO₄] are structural components. Under different conditions, boron may exist as trigonal [BO₃] or boron-oxygen tetrahedron [BO₄]. At high-temperature melting conditions, it is generally difficult to form boron-oxygen tetrahedra, and it can only exist as trihedrons. However, at low temperatures, under certain conditions, boron... 3+ It tends to capture free oxygen to form tetrahedra, making the structure more compact and increasing the low-temperature viscosity of the glass. However, because it has the characteristic of decreasing glass viscosity at high temperatures and increasing it at low temperatures, and is also a major component in reducing the glass refractive index, its content range is relatively small. The preferred weight percentage of boric acid in the core rod glass is 20-30%. When the boric acid content is below 20%, it cannot act as a solvent aid and will also reduce the chemical stability of the glass; while when the boric acid content is above 30%, it will reduce the glass refractive index and increase the glass's tendency to phase separation.

[0032] La2O3, introduced by lanthanum oxide, is a lanthanide rare earth oxide that can improve the refractive index of glass. The preferred weight percentage of lanthanum oxide is 19.5-30%, but when the lanthanum oxide content is greater than 30%, it will cause an increase in the coefficient of thermal expansion of the glass.

[0033] Introducing ZnO with zinc oxide results in a high band gap and excitation binding energy, leading to a high absorption coefficient under certain radiation conditions. A small amount of ZnO can improve the radiation resistance of glass. The weight percentage of zinc oxide is 1.1-10%. A ZnO content greater than 10% will reduce the chemical stability and thermal expansion coefficient of the glass, and increase its tendency to crystallize.

[0034] Nb₂O₅, introduced as niobium oxide, is also a rare earth oxide that increases the refractive index of glass and partially replaces La₂O₃. According to particle hybridization theory, the introduction of multiple particles can improve the stability of the glass structure. The weight percentage of niobium oxide is 1.1-10%, but when the niobium oxide content is greater than 10%, it will cause an increase in the density and coefficient of thermal expansion of the glass.

[0035] BaO, introduced in the form of barium carbonate, is an external oxide of the glass structure network. It has a high absorption coefficient under certain radiation conditions, which can improve the radiation resistance of the glass. The weight percentage of barium carbonate raw material is preferably 10.1-20%. If the content of barium carbonate raw material is greater than 20%, it will increase the crystallization temperature of the glass and increase the tendency of the glass to crystallize.

[0036] HfO2, introduced with hafnium oxide, has a wide transparency region from ultraviolet (UV) to infrared (IR), giving the glass a good light transmittance in the ultraviolet band, allowing ultraviolet light to pass through more easily. The weight percentage of hafnium oxide is 0-3%, but when the hafnium oxide content is greater than 3%, it will disrupt the chemical balance of the glass, making it prone to crystallization.

[0037] Ta₂O₅, introduced as tantalum oxide, is also a rare earth oxide. It increases the refractive index of the glass and partially replaces La₂O₃. According to particle hybridization theory, the introduction of multiple particles can improve the stability of the glass structure. The weight percentage of tantalum oxide is 5.1-10%, but when the tantalum oxide content is greater than 10%, it will cause an increase in the density and coefficient of thermal expansion of the glass.

[0038] Y₂O₃, introduced as yttrium oxide, is also a rare earth oxide. It can increase the refractive index of glass and partially replace La₂O₃. According to the particle hybridization theory, the introduction of multiple particles can improve the stability of the glass structure. The weight percentage of yttrium oxide is 1.1-7%, but when the yttrium oxide content is greater than 7%, it will cause an increase in the density and coefficient of thermal expansion of the glass.

[0039] SrO, introduced in the form of strontium carbonate, is an alkaline earth metal oxide and an outer oxide of the glass structure network. It has a high absorption coefficient under certain radiation conditions, which can improve the radiation resistance of the glass. The weight percentage of strontium carbonate raw material is preferably 0-5%. When the content of strontium carbonate raw material is greater than 5%, it will reduce the chemical stability of the glass and increase the thermal expansion coefficient of the glass.

[0040] Al₂O₃, introduced as alumina, is an intermediate oxide in glass and can improve the radiation resistance of glass while reducing its tendency for phase separation. Replacing some SiO₂ with Al₂O₃... 3+ Preferentially, it captures free oxygen to form [AlO4], which then enters the glass network. 3+ Occupy Si 4+ The location. Due to Al 3+ and Si 4+ Different valence states require alkali metal ions to fill and balance the valence state. Broken structural chains in the glass are reconnected, making the glass structure more compact and reducing the amount of non-bridging oxygen, thus improving the glass's radiation resistance. Therefore, within a certain content range, it can become a major component of the glass network, similar to SiO2. The alumina content is 0.5-7% by weight. When the alumina content exceeds 7%, it significantly increases the high-temperature viscosity of the glass and also raises the melting temperature.

[0041] Na₂O, introduced in the form of sodium carbonate, is an alkali metal oxide and an outer oxide of the glass network structure. Na₂O repairs the break points between [SiO₄] and [BO₃], transforming the triangular layered structure of [BO₃] into a tetrahedron of [BO₄], thus strengthening the network connections, increasing the number of bridging oxygen atoms, and shifting the intrinsic ultraviolet absorption towards shorter wavelengths, thereby improving the glass's broadband transmittance. The preferred weight percentage of sodium carbonate is 0-5%. A sodium carbonate content greater than 5% increases the glass's refractive index and coefficient of thermal expansion, and also increases its tendency to crystallize.

[0042] CeO2, introduced by cerium oxide, is a rare earth oxide. It utilizes the fact that cerium is a variable-valence element, and under radiation, it is in a high-valence state (Ce). 4+ It can first absorb high-energy electrons or free electrons induced by radiation, causing a change in the valence state of the ions without establishing color centers, thus achieving radiation resistance. However, after cerium changes its valence, the new valence state causes absorption of ultraviolet and visible light, which also leads to a decrease in the transmittance of the fiber optic imaging array. Ce... 4+ It exhibits strong absorption in the visible light region, transforming into Ce. 3+ At this point, absorption in the spectral region above 300 nm is very small. By appropriately introducing a suitable amount of Ce and precisely controlling the valence state through an oxygen-enriched melting process, the amount of cerium with variable valence is minimized while still meeting radiation resistance requirements. This resolves the contradiction between ultraviolet transmission (avoiding as many variable valence elements as possible in the composition) and radiation resistance (introducing cerium with variable valence to absorb high-energy electrons generated by high-energy radiation and prevent color center formation). This achieves both radiation resistance and high transmittance in the ultraviolet region. The weight percentage of cerium oxide is 0.05-2%. A cerium oxide content greater than 2% increases the glass's tendency to crystallize and reduces its transmittance.

[0043] In some specific embodiments of the present invention, the tubing mixture, by mass percentage, comprises: 60-75% quartz sand, 1.5-15% boric acid, 1-5% alumina, 1-10% sodium carbonate, 1-8% potassium hydrofluoric acid, 1-8% calcium fluoride, 0-5% basic magnesium carbonate, 0-8% lithium carbonate, 0-5% zinc oxide, and 0-2% cerium oxide, wherein the total content of impurities Fe, Cu, and Mn is ≤3ppm; and the total content of impurities Nd, Pr, U, Er, Eu, Tb, and Dy is ≤2ppm. The tubing mixture is melted, clarified, stirred, shaped, and annealed to obtain the tubing; all components in the tubing exist in oxide form, i.e., it contains SiO2, B2O3, Al2O3, Na2O, K2O, CaO, MgO, Li2O, ZnO, and CeO2.

[0044] In the aforementioned tubular glass, SiO2 is introduced in the form of quartz sand, forming the main body of the glass skeleton and playing a major role in the glass skeleton. The weight percentage of quartz sand in the tubular glass is 60-75%. When the content of quartz sand raw material is less than 60%, it is difficult to obtain glass with a low refractive index, and it also reduces the chemical stability of the glass; while when the content of quartz sand raw material is higher than 75%, the high-temperature viscosity of the glass increases, resulting in excessively high glass melting temperature, and the coefficient of thermal expansion of the glass also decreases.

[0045] B₂O₃, introduced in the form of boric acid, is a glass-forming oxide and a component of the glass framework. It also acts as a flux to reduce the viscosity of the glass melt. Boron-oxygen trigonal [BO₃] and boron-oxygen tetrahedron [BO₄] are structural components. Under different conditions, boron may exist as trigonal [BO₃] or boron-oxygen tetrahedron [BO₄]. At high-temperature melting conditions, it is generally difficult to form boron-oxygen tetrahedra, and it can only exist as trihedrons. However, at low temperatures, under certain conditions, boron... 3+ It tends to capture free oxygen to form tetrahedrons, making the structure more compact and increasing the low-temperature viscosity of the glass. However, because it has the characteristic of decreasing glass viscosity at high temperatures and increasing it at low temperatures, and is also a major component in reducing the glass refractive index, its content range is relatively small. The preferred weight percentage of boric acid in the tubular glass is 1.5-15%. When the boric acid content is greater than 15%, it will decrease the glass refractive index and also increase the glass's tendency to separate phases.

[0046] Al₂O₃, introduced as alumina, is an intermediate oxide in glass and can improve the radiation resistance of glass while reducing its tendency for phase separation. Replacing some SiO₂ with Al₂O₃... 3+ Preferentially, it captures free oxygen to form [AlO4], which then enters the glass network. 3+ Occupy Si 4+ The location. Due to Al 3+ and Si 4+ Different valence states require alkali metal ions to fill and balance the valence state. Broken structural chains in the glass are reconnected, making the glass structure more compact and reducing the amount of non-bridging oxygen, thus improving the glass's radiation resistance. Therefore, within a certain content range, it can become a major component of the glass network, similar to SiO2. The alumina content is 1-5% by weight; when the alumina content exceeds 5%, it significantly increases the high-temperature viscosity of the glass and simultaneously raises the glass's melting temperature.

[0047] Na₂O, introduced in the form of sodium carbonate, is an alkali metal oxide and an outer oxide of the glass network structure. Na₂O repairs the break points between [SiO₄] and [BO₃], transforming the triangular layered structure of [BO₃] into a tetrahedron of [BO₄], thus strengthening the network connections, increasing the number of bridging oxygen atoms, and shifting the intrinsic ultraviolet absorption towards shorter wavelengths, thereby improving the glass's broadband transmittance. The preferred weight percentage of sodium carbonate is 1-10%. A sodium carbonate content greater than 10% increases the glass's refractive index and coefficient of thermal expansion, and also increases its tendency to crystallize.

[0048] K₂O, introduced in the form of potassium fluoride, is an alkali metal oxide and an outer oxide of the glass network structure. K₂O repairs the breakpoints between [SiO₄] and [BO₃], transforming the triangular layered structure of [BO₃] into a tetrahedron of [BO₄], thus strengthening the network connections, increasing the number of bridging oxygen atoms, and shifting the intrinsic ultraviolet absorption towards shorter wavelengths, thereby improving the glass's broadband transmittance. - The introduction of F can fill oxygen vacancies in the glass, thereby repairing structural defects and improving glass transmittance. Meanwhile, F... - To achieve a stable octet structure, the strong binding effect of potassium fluoride on outer electrons reduces the number of high-energy free electrons generated by irradiation, preventing the formation of color centers and improving the glass's radiation resistance. The preferred weight percentage of potassium fluoride is 1-8%. A potassium fluoride content greater than 8% increases the glass's refractive index and coefficient of thermal expansion, and also increases its tendency to crystallize.

[0049] CaO is introduced in the form of calcium fluoride to improve the glass's radiation resistance and broad spectral transmittance. - The introduction of F can fill oxygen vacancies in the glass, thereby repairing structural defects and improving glass transmittance. Meanwhile, F... - To achieve a stable octet structure, the strong binding effect of calcium fluoride on outer electrons reduces the number of high-energy free electrons generated by irradiation, preventing the formation of color centers and improving the glass's radiation resistance. The weight percentage of calcium fluoride raw material is 1-8%. A calcium fluoride content greater than 8% will reduce the glass's chemical stability and increase its tendency to crystallize.

[0050] MgO is introduced in the form of basic magnesium carbonate, which is an outer oxide of the glass structure network and is used to adjust the glass crystallization temperature. The weight percentage of basic magnesium carbonate raw material is 0-5%. If the content of basic magnesium carbonate raw material is greater than 5%, it will increase the tendency of glass to crystallize.

[0051] Li₂O, introduced in the form of lithium carbonate, is an external oxide of the glass network structure. Lithium oxide has a small ionic radius and high electronegativity, making it easy to enter the glass network structure and exert a strong attraction on surrounding molecules. This contributes to the densification of the glass structure, reduces internal defects and scattering centers, thereby improving the glass's transmittance. The weight percentage of lithium carbonate is 0-8%; a lithium carbonate content greater than 8% will increase the glass's coefficient of thermal expansion.

[0052] Introducing zinc oxide (ZnO) results in a high bandgap and excitation binding energy, leading to a high absorption coefficient under certain radiation exposure conditions. A small amount of ZnO can improve the radiation resistance of glass. The weight percentage of zinc oxide is 0-5%. A zinc oxide content greater than 5% will reduce the chemical stability and thermal expansion coefficient of the glass, and increase its tendency to crystallize.

[0053] CeO2, introduced by cerium oxide, is a rare earth oxide. It utilizes the fact that cerium is a variable-valence element, and under radiation, it is in a high-valence state (Ce). 4+ It can first absorb high-energy electrons or free electrons induced by radiation, causing a change in the valence state of the ions without establishing color centers, thus achieving radiation resistance. After cerium changes its valence, the element in the new valence state absorbs ultraviolet and visible light, which also leads to a decrease in the transmittance of the fiber optic imaging array. Ce... 4+ It exhibits strong absorption in the visible light region, transforming into Ce. 3+ At this point, absorption in the spectral region above 300 nm is very small. By appropriately introducing a suitable amount of Ce and precisely controlling the valence state through an oxygen-enriched melting process, the amount of cerium with variable valence is minimized while still meeting radiation resistance requirements. This resolves the contradiction between ultraviolet transmission (avoiding as many variable valence elements as possible in the composition) and radiation resistance (introducing cerium with variable valence to absorb high-energy electrons generated by high-energy radiation and prevent color center formation). This achieves both radiation resistance and high transmittance in the ultraviolet region. The weight percentage of cerium oxide is 0-2%. A cerium oxide content greater than 2% increases the glass's tendency to crystallize and reduces its transmittance.

[0054] In the above-mentioned steps for preparing the core rod and tubing, the purity control of the raw materials is crucial. This is because harmful impurities may be present in the raw materials, such as transition metal ions and heavy metal ions. These ions have low electron transition energies and undergo transitions upon irradiation with high-energy rays. They exhibit significant absorption of ultraviolet light in the ultraviolet region. Therefore, to avoid their impact on the ultraviolet transmittance of the glass material, this invention strictly controls the content of harmful impurities such as oxides or salts in the preparation of the core rod and tubing. All raw materials used in the preparation of the mixture are high-purity, and the contents of Fe, Cu, Mn, etc., are strictly controlled to ensure that the content of coloring elements in all raw materials is below 3 ppm. When using rare earth oxides such as Y, La, Ta, Nb, and Ce, the introduction of impurity elements such as Nd, Pr, U, Er, Eu, Tb, and Dy is strictly prohibited, and their total content is controlled below 2 ppm. This ensures that the glass prepared by this technical solution has excellent overall performance.

[0055] Furthermore, this step requires high purity of raw materials. Therefore, the containers and tools used in the mixing process also need strict control. For example, the material of the container for preparing the mandrel mixture must be a non-metallic, alkali-resistant material; the material of the container for preparing the tubing mixture must also be a non-metallic material; if plastic products are used, they should preferably be colorless and transparent. The reason for this is that since the container, such as the crucible, is in direct contact with the glass, any impurities, whether from the crucible material or within the crucible, if introduced into the mixture, may melt into the glass during subsequent melting, adversely affecting the quality and performance of the glass. For example, if a platinum crucible is used, platinum particles or ions may enter the glass, leading to UV absorption and negatively impacting the glass's light transmittance. On the one hand, depending on the acidity or alkalinity of the glass, if the glass composition is incompatible with the container material, the glass composition may severely corrode the container, causing significant changes in the glass composition. This corrosion may even lead to container leakage, such as a leaky crucible, which could be detrimental to improving the quality of glass melting. In this invention, the core glass composition is a silicon-boron-lanthanum-barium system, which is generally alkaline. Therefore, it is more likely to corrode quartz and corundum crucibles. Therefore, this invention preferably uses a magnesium oxide crucible instead of a platinum crucible for the core glass. Furthermore, according to the composition of the tubular glass in this invention, a quartz crucible is preferably used, and a high-purity silicon oxide coating is applied to the crucible surface to reduce the influence of the crucible composition on the glass composition and reduce the introduction of impurities.

[0056] In the melting step of the mixture, the mixture can be directly added to the container for melting; however, in order to improve melting efficiency and the quality of the molten glass, the present invention preferably adds the mixture to the melting container in batches during melting; in some specific embodiments of the present invention, it is preferred to add the mixture to the container in 3-5 batches, with an interval of 0.5-2 hours between each batch; adding the mixture in batches in this way can more efficiently complete the melting of the glass composition.

[0057] The melting process of the glass mixture can be adjusted according to its specific composition. Under the composition formulation conditions designed in this invention, the preferred melting temperature of the mandrel mixture is 1450-1520℃, and the preferred melting temperature of the tubular mandrel mixture is 1350-1400℃, so that the glass composition can be melted quickly.

[0058] After the glass mixture is completely melted, the molten glass can be clarified and stirred. In this step, the preferred clarification and stirring temperature for the mandrel glass is 1520-1600℃, and the clarification and stirring time is 1-2 hours. Forced stirring is preferably performed throughout the clarification process. Preferably, the stirrer is also made of a non-metallic, alkali-resistant material to avoid contact with the molten glass and the introduction of harmful impurities. For the tubular glass, the preferred clarification and stirring temperature is 1460-1530℃, and the clarification and stirring time is 1-2 hours. Stirring is preferably performed throughout the clarification process. Preferably, the stirrer is also made of a non-metallic material to avoid contact with the molten glass and the introduction of harmful impurities. In the above clarification steps, a double-bladed impeller is preferred to improve the stirring effect.

[0059] To ensure high transmittance of the resulting glass under irradiation conditions, this invention strictly limits the introduction of oxygen into the molten glass during the melting and refining stages to create a strongly oxidizing atmosphere. The amount of oxygen introduced adjusts the concentration of the oxidizing atmosphere in the molten glass, allowing the variable-valence element to melt in an oxygen-rich environment. This ensures that the molten glass contains sufficient high-valence variable elements to meet the glass's radiation resistance requirements, while preventing an excessive amount of high-valence variable elements that could absorb light and negatively impact the glass's transmittance. In some specific embodiments of this invention, the oxygen flow rate into the molten glass is preferably 0.1–0.3 mol / L / min for the mandrel glass and 0.04–0.18 mol / L / min for the tubular glass. This allows for precise adjustment of the valence state of the radiation-resistant variable-valence element cerium, ensuring high transmittance and high radiation resistance of the mandrel glass under irradiation conditions.

[0060] Glass melting is generally carried out in an open crucible. Since the decomposition of raw materials in the glass mixture may produce a large amount of volatile gases, and some components of the glass composition are also volatile, these volatile components can corrode the material of the melting furnace. This corroded material may also affect the glass itself through the crucible opening. Therefore, this invention preferably uses a refractory material for the melting and refining furnace. By strictly controlling the content of heavy metals, such as lead, cadmium, and mercury, to ≤5ppm, the adverse effects of the furnace material on the quality of the molten glass are directly reduced. Furthermore, by preferably using a corrosion-resistant and high-temperature-resistant refractory material, preferably with a temperature resistance ≥1700℃, the corrosion of the melting furnace by volatile glass components can be avoided or reduced, thereby indirectly reducing the adverse effects of the furnace material on the quality of the molten glass.

[0061] Furthermore, to avoid cross-contamination of the glass due to the erosion of the refractory material in the melting furnace, the present invention preferably uses a dedicated furnace for heating the container. That is, the melting furnace for preparing mandrel glass is only used for melting mandrel glass of this formulation, and the melting furnace for preparing tubular glass is only used for melting tubular glass of this formulation, thereby avoiding or reducing cross-contamination caused by the furnace material. The present invention can also be further preferred to replace it periodically according to usage and erosion conditions, so as to prevent harmful impurities such as Fe and Ti in the refractory material from entering the glass, thereby avoiding or reducing the influence of the melting furnace on the composition of the molten glass.

[0062] Mandrel glass discharge involves injecting molten glass into a mandrel mold and casting it into mandrel glass of the required specifications; annealing yields the mandrel. Tube glass discharge involves injecting molten glass into a tube mold and casting it into tube glass of the required specifications; annealing yields the tube. The discharge, forming, and annealing temperatures and times of the molten glass can be adjusted according to the actual composition of the glass composition. In some specific embodiments of the present invention, based on the composition of the glass composition, it is preferred that the discharge temperature of the mandrel glass be 1360-1400℃, the annealing temperature be 600-650℃, and the annealing time be 2-4 hours; it is preferred that the discharge temperature of the tube glass be 1300-1350℃, the annealing temperature be 550-600℃, and the annealing time be 2-4 hours.

[0063] Finally, the tubing is fitted over the outside of the mandrel to obtain the mandrel-tube assembly; wherein, the difference between the thermal expansion coefficient of the mandrel glass and the thermal expansion coefficient of the tubing glass is 1×10⁻⁶. -7 / ℃~10×10 -7 / ℃; the difference between the softening temperature of the mandrel glass and the softening temperature of the tubular glass is 10~25℃; the difference between the refractive index of the mandrel glass and the refractive index of the tubular glass is >0.3; both the mandrel glass and the tubular glass remain chemically stable at 810℃.

[0064] The present invention also proposes an application of the broadband response radiation-resistant rod-tube assembly described above in the fabrication of a broadband response radiation-resistant fiber optic imaging array.

[0065] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0066] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0067] I. Preparation of mandrel glass:

[0068] Raw material requirements: Quartz sand (4N, less than 5% of material on 160μm sieve and less than 5% of material under 40μm sieve), boric acid (analytical grade, less than 10% of material on 400μm sieve and less than 10% of material under 63μm sieve), strontium carbonate (analytical grade, purity ≥99.0%), lanthanum oxide (5N), niobium oxide (5N), yttrium oxide (5N), tantalum oxide (5N), zinc oxide (analytical grade), aluminum oxide (analytical grade, average particle size 50μm), sodium carbonate (analytical grade), barium carbonate (analytical grade), hafnium oxide (analytical grade), cerium oxide (4N). Impurities in high-purity reagent raw materials must be strictly controlled; the total content of coloring elements such as Fe, Cu, and Mn must be <3ppm. When using rare earth oxides such as Y, La, Ta, and Nb, the introduction of impurity elements such as Nd, Pr, U, Er, Eu, Tb, and Dy must be strictly prohibited, and their total content must be controlled to <2ppm.

[0069] Example 1-1

[0070] Melting of the mandrel glass: Select raw materials according to the glass composition in Example 1-1 of Table 1-1. Weigh the raw materials according to the batching table, mix them evenly, and place them in a magnesium oxide crucible. All containers and utensils used in the batching and melting process are made of non-metallic materials, and the plastic products are colorless and transparent. The lead, cadmium, and mercury content in the furnace top refractory material is controlled below 5 ppm. It is corrosion-resistant and can withstand temperatures above 1700℃. The melting furnace must be dedicated to this purpose to avoid cross-contamination caused by refractory material corrosion. Replace the refractory material regularly according to its use and corrosion status to prevent harmful impurities such as Fe and Ti from entering the glass.

[0071] The mixture was added to the crucible in four batches every hour for high-temperature melting at 1500°C. After the raw material mixture melted, it was clarified and stirred at 1550°C for 1.5 hours using a double-bladed stirrer to improve the stirring effect. During this melting and clarification stage, the oxygen valve was opened to introduce oxygen into the glass melt at a flow rate of 0.2 mol / L / min to create a strong oxidizing atmosphere. The molten and clarified glass melt was discharged at 1370°C and cast into a mold to form the desired glass. After the glass cooled and solidified, it was annealed at 640°C for 2.5 hours to obtain the core glass of this invention.

[0072] Testing revealed that the core rod glass prepared in this embodiment, at a thickness of 100 mm, exhibited a spectral transmittance of 67% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreased by 2.6%; the refractive index was 1.8023; and the average linear thermal expansion coefficient in the temperature range of 30–300 °C was 91.0 × 10⁻⁶. -7 / ℃; it does not crystallize when kept at 810℃ for 5 hours.

[0073] Examples 1-2 to 1-5

[0074] The process is the same as in Example 1-1. The formulation of the core rod glass composition, the purity of the raw materials and the process parameters are shown in Table 1. The test results are also shown in Table 1.

[0075] Table 1 Chemical composition, process parameters, and properties of the core rod glass in Examples 1-1 to 1-5

[0076]

[0077]

[0078] Notes: a′ represents the total content of coloring elements such as Fe, Cu, and Mn in high-purity reagent quartz sand, lanthanum oxide, niobium oxide, yttrium oxide, tantalum oxide, and cerium oxide, in ppm; b′ represents the total content of impurities Nd, Pr, U, Er, Eu, Tb, and Dy in rare earth oxides such as lanthanum oxide, niobium oxide, yttrium oxide, tantalum oxide, and cerium oxide, in ppm; c′ represents the transmittance of the 330nm–2000nm spectrum, in %; d′ represents the transmittance attenuation rate (at 350nm after 500h irradiation at a dose of 6.4kGy), in %; e′ represents the refractive index; f′ represents the average linear thermal expansion coefficient in the range of 30–300℃, in ×10⁻¹⁰. -7 / ℃.

[0079] II. Preparation of tubular glass:

[0080] Raw material requirements: Quartz sand (4N, less than 5% of material on 160μm sieve and less than 5% of material under 40μm sieve), boric acid (analytical grade, less than 10% of material on 400μm sieve and less than 10% of material under 63μm sieve), zinc oxide (analytical grade), aluminum oxide (analytical grade, average particle size 50μm), sodium carbonate (analytical grade), potassium hydrofluoric acid (analytical grade), calcium fluoride (analytical grade), basic magnesium carbonate (chemically pure, average particle size 50μm), lithium carbonate (analytical grade), cerium oxide (4N). Impurities in high-purity raw materials must be strictly controlled. The total content of coloring elements Fe, Cu, and Mn must be <3ppm. When using rare earth cerium oxide, the introduction of impurity elements such as Nd, Pr, U, Er, Eu, Tb, and Dy must be strictly prohibited, and their total content must be controlled to <2ppm.

[0081] Example 2-1

[0082] Melting of tubular glass: Select raw materials according to the glass composition in Example 2-1 of Table 2. Weigh the raw materials according to the batching table, mix them evenly, and place them in a quartz crucible with a high-purity silica coating on the surface. All containers and utensils used in the batching and melting process are made of non-metallic materials, and the plastic products are colorless and transparent. The lead, cadmium, and mercury content in the furnace roof refractory material is controlled below 5 ppm. It is corrosion-resistant and can withstand temperatures above 1700℃. The melting furnace must be dedicated to this purpose to avoid cross-contamination caused by refractory material corrosion. Replace the refractory material regularly according to its use and corrosion status to prevent harmful impurities such as Fe and Ti from entering the glass.

[0083] The mixture was added to the crucible in five batches every 0.5 hours for high-temperature melting at 1360°C. After the raw material mixture melted, it was clarified and stirred at 1470°C for 2 hours using a double-bladed stirrer to improve the stirring effect. During this melting and clarification stage, the oxygen valve was opened to introduce oxygen into the glass melt at a flow rate of 0.044 mol / L / min, creating a strong oxidizing atmosphere. The molten and clarified glass melt was discharged at 1300°C and cast into a mold to form the desired glass. After the glass cooled and solidified, it was annealed at 550°C for 4 hours to obtain the tubular glass of this invention.

[0084] Testing revealed that the tubular glass produced in this embodiment, at a thickness of 100 mm, exhibited a spectral transmittance of 75.8% in the wavelength range of 330–2000 nm; after irradiation at a dose of 6.4 kGy for 500 h, the transmittance at 350 nm decreased by 2.3%; the refractive index was 1.4985; and the average linear thermal expansion coefficient in the temperature range of 30–300 °C was 82 × 10⁻⁶. -7 / ℃; it does not crystallize when kept at 910℃ for 5 hours.

[0085] Examples 2-2 to 2-5

[0086] The process is the same as in Example 2-1. The formulation, raw material purity and process parameters of the tubular glass composition are shown in Table 2, and the test results are also shown in Table 2.

[0087] Table 2 Chemical composition, process parameters, and properties of the tubular glass in Examples 2-1 to 2-5

[0088]

[0089]

[0090] Notes: a represents the total content of coloring elements such as Fe, Cu, and Mn in high-purity reagent quartz sand and cerium oxide, in ppm; b represents the total content of impurities Nd, Pr, U, Er, Eu, Tb, and Dy in cerium oxide, in ppm; c represents the transmittance of the 330nm–2000nm spectrum, in %; d represents the transmittance attenuation rate (at 350nm after 500h irradiation at a dose of 6.4kGy), in %; e represents the refractive index; f represents the average linear thermal expansion coefficient in the range of 30–300℃, in ×10⁻¹⁰. -7 / ℃.

[0091] III. Preparation of Rod-Tube Assembly

[0092] Examples 3-1 to 3-16 and Comparative Examples 1 to 9

[0093] The mandrels prepared in Examples 1-1 to 1-5 were combined with the tubing prepared in Examples 2-1 to 2-5 to obtain mandrel-tube assemblies. The outer diameter of the mandrel was 30.0 to 32.0 mm, the inner diameter of the tubing was 30.5 to 32.5 mm, the thickness of the tubing was 3.2 to 4.2 mm, and the difference between the outer diameter of the mandrel and the inner diameter of the tubing was 0.5 mm. The compatibility results of the mandrel-tubing performance are shown in Table 3.

[0094] The fiber optic image transmission array was fabricated by drawing single filaments at a temperature of 780–800℃ and a rod speed of 1.0–1.5 mm / min, drawing multifilaments at a temperature of 820–840℃ and a rod speed of 1.4–2.0 mm / min, and drawing multifilaments again at a temperature of 810–820℃ and a rod speed of 1.0–1.5 mm / min. The arrays were then arranged in a plate, hot-melted at 600–650℃, and finished. The machinability of each rod-tube assembly and the quality of the fiber optic image transmission array fabricated from it were evaluated, and the results are shown in Table 3.

[0095] Table 3. Performance of the mandrel glass and tubular glass examples

[0096]

[0097]

[0098] As shown in Table 1, the core rod glass prepared in this embodiment exhibits excellent overall performance, simultaneously satisfying broad spectral response, radiation resistance, and high refractive index, with high ultraviolet transmittance. As shown in Table 2, the tubular glass prepared in this embodiment exhibits excellent overall performance, simultaneously satisfying broad spectral response, radiation resistance, and low refractive index, with high ultraviolet transmittance. As shown in Table 3, the optical fibers in Comparative Examples 4, 6, 7, and 9 broke after drawing. This may be due to the significant difference in thermal expansion coefficients between the core rod and the tubular glass, resulting in poor matching and causing different shrinkage rates of the core and tubular glass during cooling after drawing. The core glass shrinks faster than the tubular glass, leading to stress concentration at the interface and causing optical fiber breakage. Comparative Examples 1-5 exhibited poor fiber diameter roundness after drawing. Microscopic observation of the single-filament cross-section revealed insufficient bonding between the core and sheath, with minute gaps. This may be due to a small core-skin softening temperature difference, meaning the difference in softening states between the core and sheath glass was not significant, resulting in poor matching. Consequently, during drawing, the two could not fuse in their optimal state, leading to poor fiber diameter roundness and core-skin separation, thus reducing the structural strength and stability of the fiber optic image converter. Comparative Examples 7-8, after being fabricated into fiber optic image arrays, showed light leakage. This may be due to a large core-skin softening temperature difference, causing a significant difference in softening states between the core and sheath glass during drawing, resulting in poor matching. When the core glass reached a good, drawable softening state, the sheath glass had already softened excessively, preventing proper matching during flow and fusion. This resulted in a thinner sheath during fiber drawing, causing the transmitted light to leak because the core deformation prevented it from meeting the total internal reflection condition.

[0099] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a broadband spectral response radiation-resistant rod-tube assembly, characterized in that, It comprises the following steps: S21 raw material metering, mixing, to obtain the core rod mixture and the skin tube mixture; the core rod mixture comprises, in mass percentage: quartz sand 10-15%, boric acid 20-30%, lanthanum oxide 19.5-30%, zinc oxide 1.1-10%, niobium oxide 1.1-10%, barium carbonate 10.1-20%, hafnium oxide 0.1-3%, tantalum oxide 5.1-10%, yttrium oxide 1.1-7%, strontium carbonate 0.1-5%, aluminum oxide 0.5-7%, sodium carbonate 0.1-5%, cerium oxide 0.05-2%; the skin tube mixture comprises: quartz sand 60-75%, boric acid 1.5-15%, aluminum oxide 1-5%, sodium carbonate 1-10%, potassium bifluoride 1-8%, calcium fluoride 1-8%, basic magnesium carbonate 0.1-5%, lithium carbonate 0.1-8%, zinc oxide 0.1-5%, cerium oxide 0.1-2%; S22 melting and refining stirring of the core rod mixture and the skin tube mixture respectively, discharging, casting forming, annealing, to obtain the core rod or the skin tube; the glass of the core rod has a spectral transmittance ≥65% at a thickness of 100mm, in the wavelength range of 330-2000nm; the transmittance attenuation rate at 350nm is ≤3% after irradiation for 500h under an irradiation dose of 6.4kGy; the glass of the skin tube has a spectral transmittance ≥75% at a thickness of 100mm, in the wavelength range of 330-2000nm; the transmittance attenuation rate at 350nm is ≤3% after irradiation for 500h under an irradiation dose of 6.4kGy; oxygen is introduced into the glass liquid in the melting and refining stirring step; S23, the skin tube is sleeved outside the core rod to obtain a rod-tube assembly; wherein the difference between the thermal expansion coefficient of the core rod glass and the thermal expansion coefficient of the skin tube glass is 1×10 -7 / ℃~10×10 -7 / ℃; the difference between the softening temperature of the core rod glass and the softening temperature of the skin tube glass is 10~25℃; the difference between the refractive index of the core rod glass and the refractive index of the skin tube glass is >0.3; and the core rod glass and the skin tube glass are both chemically stable at 810℃.

2. The production method according to claim 1, characterized by, The total content of impurities Fe, Cu and Mn in the core rod mixture and the skin tube mixture is ≤3ppm; the total content of impurities Nd, Pr, U, Er, Eu, Tb and Dy is ≤2ppm; the appliances for preparing and melting the core rod mixture are made of non-metallic alkali-resistant materials; the appliances for preparing and melting the skin tube mixture are made of non-metallic materials; the smelting furnace for melting and refining is made of refractory material, and the content of heavy metals is ≤5ppm.

3. The production method according to claim 2, characterized by, The container for melting the core rod mixture is a crucible made of magnesium oxide; the container for melting the skin tube mixture is a crucible made of quartz, and the surface of the crucible is provided with a silica coating.

4. The preparation method according to claim 2, characterized in that, The refractory material is an erosion-resistant and high-temperature-resistant material, and the temperature resistance is ≥1700℃.

5. The preparation method according to claim 2, characterized in that, The smelting furnace for melting the core rod mixture is exclusively used for the preparation of the core rod glass; or, the smelting furnace for melting the skin tube mixture is exclusively used for the preparation of the skin tube glass.

6. The preparation method according to claim 2, characterized in that, The melting of the mixture is carried out by adding the mixture into the container for 3-5 times, and the interval between each time is 0.5-2 hours.

7. The preparation method according to claim 2, characterized in that, The melting temperature of the core rod mixture is 1350-1400℃; the refining stirring temperature is 1460-1530℃, and the refining stirring time is 1-2h; the discharge temperature is 1300-1350℃; the annealing temperature is 550-600℃, and the annealing time is 2-4h; or the melting temperature of the skin tube mixture is 1350-1400℃; the refining stirring temperature is 1460-1530℃, and the refining stirring time is 1-2h; the discharge temperature is 1300-1350℃; the annealing temperature is 550-600℃, and the annealing time is 2-4h.

8. The preparation method according to claim 2, characterized in that, During the preparation of the core rod, the flow rate of oxygen introduced into the glass liquid is 0.1-0.3mol / L / min; or during the preparation of the skin tube, the flow rate of oxygen introduced into the glass liquid is 0.04-0.18mol / L / min.

9. Use of the wide spectral response radiation resistant rod-tube assembly prepared according to the preparation method in any one of claims 1 to 8 in the preparation of a wide spectral response radiation resistant optical fiber image array.

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