Rare earth ion-doped borosilicate scintillator glass and its preparation method and application

Abstract

The present invention discloses a rare earth ion-doped borosilicate scintillator glass and its preparation method and application. The rare earth ion-doped borosilicate scintillator glass, by mass percentage, comprises: 23-27% of silicon dioxide; 7-10% of boron trioxide; 1-3% of aluminum fluoride; 1-3% of aluminum oxide; 11-15% of strontium oxide; 9-13% of calcium oxide; 35-38% of gadolinium oxide; 1-3% of cerium dioxide. The rare earth ion-doped borosilicate scintillator glass prepared by the present invention has an average transmittance of 84%-87% at 300-600 nm, a light yield of 1206-1296 ph / MeV, a density of 5.81-5.96 g / cm<supgt;3< / supgt;, a decay time of 100-128 ns, and a radiation tolerance time of 173-198 h.

Description

Technical Field

[0001] The present invention relates to a high-density and high-transmittance scintillator glass, a preparation method and an application thereof, and particularly relates to a rare earth ion-doped borosilicate scintillator glass, a preparation method and an application thereof, belonging to the technical field of scintillator glass. Background Art

[0002] In order to detect ionizing radiation and high-energy particles, high-energy ray detection technologies have been developed. Since the discovery of X-rays and later γ-rays, various detectors have been designed, such as gas ionization chambers, scintillator detectors, semiconductor detectors, and so on. As one of the most important ray detectors, scintillator detectors are widely used in high-energy physics experiments, atomic energy, medical imaging, and security. The core material, the scintillator, has an important impact on the performance of the detector. The scintillator applied in this field, as a material capable of converting high-energy rays into visible light, needs to have the characteristics of high density, high light output, high transmittance, and fast decay. With the expansion of the field of human activities, the improvement of scientific and technological levels, and the increasing demand for the use of ionizing radiation energy, new and higher requirements have been put forward for the performance of scintillation materials. Various large particle colliders need to accurately measure various particles, which requires high-performance electromagnetic calorimeters to meet the requirements. The electromagnetic calorimeter needs to have a high signal-to-noise ratio and low timing fluctuations, which requires the scintillator to have fast decay. At the same time, the calorimeter has to withstand high-energy ray radiation, which requires the scintillator to have higher radiation resistance to ensure a stable light yield. Currently, scintillators can be divided into inorganic scintillators, organic scintillators, liquid scintillators, and gas scintillators. Considering the actual needs of the calorimeters required for electron colliders, other types of scintillators are not very suitable. In theory, only high-performance glass scintillators can meet the requirements, and they have good potential in high-energy ray detection.

[0003] The development of scintillation materials has a history of more than one hundred years. Among them, inorganic scintillation materials are the most widely used and the most numerous. Inorganic scintillation materials mainly include three types: ceramic scintillation materials, crystal scintillation materials, and glass scintillation materials (i.e., scintillator glass). The scintillation performance of scintillation materials mainly includes light output, transparency, decay rate, high-energy particle stopping ability, and radiation damage resistance ability, etc. Inorganic scintillation materials have a wide range of applications in fields such as nuclear medicine imaging diagnosis, high-energy ion detection, industrial on-line non-destructive testing, and oil well exploration.

[0004] High density is an important index of scintillator glass. High-density scintillators have a strong stopping ability for high-energy particles and a strong aggregation effect, which can improve the resolution of the detector, occupy less space for equipment or projects, and are conducive to miniaturization design. Glass itself does not emit light and needs to add luminescent center ions, which are generally low-valence ions of transition metals, such as Ce 3+, Eu 2+ etc. They will reach the excited state under the conditions of high-energy rays or ionizing radiation. During the process of returning to the ground state, the energy is released in the form of photons, achieving the conversion effect. Therefore, ensuring that the glass has good internal quality can ensure that there are fewer defects, no streaks and bubbles inside the glass, enabling the glass to have better transmittance. In the preparation process of conventional glass, generally, clarifying agents are added, stirring and extending the melting time are used to improve the internal quality of the glass, making the melted glass composition uniform and bubble-free, with good internal quality. However, the above conventional glass melting method is not applicable to the melting of scintillator glass. To make the scintillator glass have a luminescence effect and ensure that the valence state of the luminescence center ions is in the low valence state, reducing agents are added during the melting process of the scintillator. Usually, the reducing agents will interact with the oxidants in the atmosphere or the oxidants in the glass body itself during the melting process, generating gases, which will lead to the formation of bubbles inside the glass. And the clarifying agents generally used for melting glass are oxidants, which contradicts maintaining a reducing atmosphere. Stirring and extending the melting time are also likely to destroy the reducing atmosphere, resulting in the oxidation of the luminescence center ions, thereby reducing the light yield, the main performance of the scintillating glass decreases, and the detection efficiency decreases, making it unable to be applied to high-energy particle detection. Summary of the Invention

[0005] In view of this, the main object of the present invention is to provide a rare earth ion-doped borosilicate scintillator glass, its preparation method and application. The technical problem to be solved is to make the scintillator glass simultaneously have the advantages of high density, fast decay, radiation resistance, high light yield and high transmittance, so as to be suitable for the application of high-energy particle detection in a circular particle accelerator.

[0006] The object of the present invention and the solution to its technical problems are achieved by the following technical solutions. A rare earth ion-doped borosilicate scintillator glass proposed by the present invention, calculated by mass percentage, includes:

[0007] Silicon dioxide (SiO2) 23 - 27%; boron trioxide (B2O3) 7 - 10%; aluminum fluoride (AlF3) 1 - 3%; aluminum oxide (Al2O3) 1 - 3%; strontium oxide (SrO) 11 - 15%; calcium oxide (CaO) 9 - 13%; gadolinium oxide (Gd2O3) 35 - 38%; cerium dioxide (CeO2) 1 - 3%.

[0008] The object of the present invention and the solution to the technical problems can also be further realized by the following technical measures.

[0009] Preferably, in the aforementioned rare earth ion-doped borosilicate scintillator glass, the rare earth ion-doped borosilicate scintillator glass further includes 1% - 3% of glucose and / or galactose and / or maltose by weight percentage.

[0010] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the rare earth ion-doped borosilicate scintillator glass contains, by mass percentage:

[0011] Silicon dioxide 25%; boron trioxide 8%; aluminum trioxide 1.5%; aluminum trifluoride 1.5%; strontium oxide 13%; calcium oxide 12.5%; gadolinium oxide 37%; cerium dioxide 1.5%.

[0012] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the average transmittance of the rare earth ion-doped borosilicate scintillator glass at 300 - 600 nm is 84% - 87%.

[0013] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the light yield of the rare earth ion-doped borosilicate scintillator glass is 1206 - 1296 ph / MeV.

[0014] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the density of the rare earth ion-doped borosilicate scintillator glass is 5.81 - 5.96 g / cm 3 .

[0015] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the decay time of the rare earth ion-doped borosilicate scintillator glass is 100 - 128 ns.

[0016] Preferably, for the foregoing rare earth ion-doped borosilicate scintillator glass, the radiation resistance time of the rare earth ion-doped borosilicate scintillator glass is 173 - 198 h.

[0017] The object of the present invention and the technical problems to be solved can be further achieved by the following technical measures. A preparation method of a rare earth ion-doped borosilicate scintillator glass proposed by the present invention includes the following steps:

[0018] S1 Weigh 23 - 27% of silicon dioxide, 7 - 10% of boron trioxide, 1 - 3% of aluminum fluoride, 1 - 3% of aluminum trioxide, 11 - 15% of strontium oxide, 9 - 13% of calcium oxide, 35 - 38% of gadolinium oxide, and 1 - 3% of cerium dioxide in sequence according to mass percentage, mix them evenly to obtain a batch material, and weigh 1 wt% - 3 wt% of an organic reducing agent based on the total weight of the batch material and add it to the batch material;

[0019] S2 After the feeding is completed, heat the batch material containing the organic reducing agent at a heating rate of 4.5 - 5.5 °C / min, and after heating to 1520 °C - 1550 °C, carry out clarification for 3 - 5 hours;

[0020] After the clarification in S3, cool down the melted glass liquid; after cooling to room temperature, reduce the air pressure of the glass liquid until it is reduced to 80 - 120 Pa; then heat up the glass liquid at a heating rate of 4.5 - 5.5 °C / min.

[0021] After starting to heat up in S4, heat the glass liquid, and after 1 - 1.5 hours, reduce the air pressure of the glass liquid until it is reduced to 5 - 10 Pa; after heating up to 1520 °C - 1550 °C, clarify the glass liquid for 1 - 3 hours.

[0022] 1 - 1.5 hours after the clarification in S5, stop heating, and after 2 - 2.5 hours, cool and anneal the melted glass until it cools to room temperature to obtain the scintillator glass.

[0023] The object of the present invention and the technical problems to be solved can also be further achieved by the following technical measures.

[0024] Preferably, in the preparation method of the rare earth ion - doped borosilicate scintillator glass described above, in step S1, in the batch material, silicon element is introduced in the form of high - purity quartz sand, boron element is introduced in the form of boric acid, aluminum element is introduced in the form of alumina or aluminum fluoride, strontium element and calcium element are introduced in the form of their carbonates, and gadolinium and cerium elements are introduced in the form of their oxides.

[0025] Preferably, in the preparation method of the rare earth ion - doped borosilicate scintillator glass described above, in step S1, the organic reducing agent is selected from at least one of maltose, galactose, and glucose.

[0026] Preferably, in the preparation method of the rare earth ion - doped borosilicate scintillator glass described above, step S5 further includes a step of precisely annealing the formed glass block after cooling to room temperature.

[0027] Preferably, in step S5 of the preparation method of the rare earth ion - doped borosilicate scintillator glass described above, the precise secondary annealing includes: heating the formed glass block from room temperature to 600 - 650 °C at a heating rate of 3 - 4 °C / min for 2 - 4 hours, then keeping it warm for 2 - 4 hours, and then cutting off the power supply to let the glass cool down to room temperature with the furnace to obtain the scintillator glass.

[0028] Preferably, the preparation method of the rare earth ion - doped borosilicate scintillator glass described above includes the following steps:

[0029] Weigh 23-27% of silicon dioxide, 7-10% of boron trioxide, 1-3% of aluminum fluoride, 1-3% of aluminum oxide, 11-15% of strontium oxide, 9-13% of calcium oxide, 35-38% of gadolinium oxide and 1-3% of cerium dioxide in sequence according to mass percentage, mix them evenly to obtain a batch material, and weigh 1wt%-3wt% of an organic reducing agent based on the total weight of the batch material and add it to the batch material, then mix evenly to obtain a batch material containing an organic reducing agent;

[0030] b At room temperature, add the batch material containing an organic reducing agent into a crucible, place the crucible in a melting furnace, turn on the heating power supply of the melting furnace, and make the melting furnace heat up at a heating rate of 4.5-5.5°C / min;

[0031] c After heating up to 1520°C-1550°C, carry out clarification for 3-5 hours;

[0032] d After the clarification is completed, turn off the heating control of the melting furnace, and let the molten glass cool down with the furnace;

[0033] e After the melting furnace cools down to room temperature, close the intake valve of the melting furnace, turn on the rotary vane vacuum pump, turn on the pre-pumping valve, turn on the circulating water cooling, and reduce the internal pressure of the melting furnace until it is reduced to 80-120 Pa;

[0034] f After the pressure of the melting furnace is reduced to 80-120 Pa, turn on the heating power supply of the melting furnace, and make the melting furnace heat up at a heating rate of 4.5-5.5°C / min;

[0035] g After starting to heat up, turn on the diffusion pump heating. After 1-1.5 hours, turn on the diffusion pump to reduce the internal pressure of the melting furnace until it is reduced to 5-10 Pa;

[0036] h After the melting furnace heats up to 1520°C-1550°C, carry out clarification for 1-3 hours;

[0037] i 1-1.5 hours after the clarification is completed, turn off the power supply of the diffusion pump and the diffusion pump heating, then turn off the power supply of the outlet valve and the rotary vane vacuum pump in sequence. After 2-2.5 hours, turn off the cooling circulating water;

[0038] j Let the molten glass cool down and anneal with the furnace. After it cools down to room temperature, open the intake valve and take out the formed glass block;

[0039] k Place the formed glass block in an annealing furnace at room temperature, heat it up to 600-650°C in 2-4 hours, then keep it warm for 2-4 hours, and then cut off the power and anneal it until it cools down to room temperature and take it out of the furnace. The time for cooling down with the furnace is 16-18 hours, and then take it out of the annealing furnace to obtain the scintillator glass.

[0040] Preferably, in the method for preparing the rare earth ion-doped borosilicate scintillator glass described above, in step b, the crucible is a high-purity fused quartz crucible.

[0041] The object of the present invention and the technical problems to be solved can also be achieved by the following technical measures. A scintillator detector proposed by the present invention includes a scintillator, and the scintillator is composed of the above-mentioned rare earth ion-doped borosilicate scintillator glass.

[0042] The object of the present invention and the technical problems to be solved can also be achieved by the following technical measures. A circular particle accelerator proposed by the present invention is characterized in that the circular particle accelerator includes the above-mentioned scintillator detector.

[0043] Compared with the prior art, the rare earth ion-doped borosilicate scintillator glass, its preparation method and application described in the present invention have the following beneficial effects:

[0044] The average transmittance of the rare earth ion-doped borosilicate scintillator glass described in the present invention at 300 - 600 nm is 84% - 87%, the light yield is 1206 - 1296 ph / MeV, the density is 5.81 - 5.96 g / cm 3 , the decay time is 100 - 128 ns; the radiation tolerance time is 173 - 198 h; it can also be applied to a circular particle accelerator to detect high-energy particles, realizing the detection of high-energy particle γ rays.

[0045] In the glass system melted in the present invention, an organic reducing agent with strong reducibility is added to keep the melting process in a reducing atmosphere, ensuring that the luminescent center ions will not be oxidized, thereby ensuring that the prepared scintillator glass has a high light yield.

[0046] Compared with inorganic reducing agents such as silicon carbide and silicon nitride, the organic reducing agent used in the present invention is relatively more likely to react fully, and the small molecules generated after the reaction will not remain in the glass and will not affect the composition of the glass itself, which is beneficial to ensuring the stability and repeatability of glass preparation.

[0047] In the present invention, the air bubbles inside the glass are removed by a negative pressure method, reducing the defects of the glass, improving the homogenization of the glass while ensuring that the valence state of the luminescent center ions remains unchanged, thereby improving the transmittance and luminescence efficiency of the scintillator glass.

[0048] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following describes the preferred embodiments of the present invention in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1Transmittance test curve of the scintillator glass of Embodiment 1 of the present invention;

[0050] Figure 2 of Embodiment 1 of the present invention 23 Na and 137 Scintillation performance test chart of the scintillator glass under Cs radiation source irradiation. Detailed implementation manners

[0051] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following combines preferred embodiments to detail the specific implementation manners, structures, features and effects of a rare earth ion-doped borosilicate scintillator glass and its preparation method and application proposed according to the present invention. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0052] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well-known to those skilled in the art; unless otherwise specified, the methods are all well-known methods in the art. Unless otherwise defined, the technical terms or scientific terms used should have the ordinary meaning as understood by those of ordinary skill in the art to which the present invention belongs. For those not specifying specific experimental steps or conditions below, the operations or conditions of the conventional experimental steps described in the literature in this field can be carried out.

[0053] The rare earth ion-doped borosilicate scintillator glass provided by some embodiments of the present invention, by mass percentage, includes:

[0054] Silicon dioxide (SiO2) 23-27%; boron trioxide (B2O3) 7-10%; aluminum fluoride 1-3%; aluminum oxide (Al2O3) 1-3%; strontium oxide (SrO) 11-15%; calcium oxide (CaO) 9-13%; gadolinium oxide (Gd2O3) 35-38%; cerium dioxide (CeO2) 1-3%.

[0055] After testing, the average transmittance of the rare earth ion-doped borosilicate scintillator glass at 300-600 nm is 84%-87%; the light yield is 1206-1296 ph / MeV; the density is 5.81-5.96 g / cm 3 ; the decay time is 100-128 ns; the radiation resistance time is 173-198 h.

[0056] In the above technical solution, in order to meet the high strength and high stability of the scintillator glass, the glass of the present invention needs to use network formers such as silica and alumina as the basic framework. By studying the influence of different elements on the luminescence performance of the scintillating glass, the influence of the relative proportion of elements on the density of the scintillating glass, and the influence of the melting process on the internal quality and transmittance of the scintillating glass, a group of components of the scintillator glass suitable for electromagnetic calorimeters is finally determined. In particular, in order to increase the density of the scintillator glass and at the same time make it have good glass-forming properties, the present invention optimizes the content and proportion of gadolinium oxide, strontium oxide, and calcium oxide, and selects a suitable content and proportion, which simultaneously meets the two necessary properties of high density and glass-forming properties. At the same time, by optimizing the reducing agent, inorganic reducing agents that are likely to color the glass are excluded, and organic reducing agents such as maltose with strong reducing properties are determined, ensuring that the cerium element in the scintillator glass is trivalent rather than tetravalent, thereby ensuring a high luminous efficiency. By designing the melting process and performing secondary melting, the scintillator glass is melted and clarified sufficiently without defects such as bubbles and streaks, so as to improve the luminescence performance of the glass. By adjusting the content of silica and boric acid in the glass, the melting performance of the glass is improved; by adjusting the content of alumina and aluminum fluoride, the crystallization performance and strength of the glass are improved; by adjusting the content of cerium dioxide, the best light yield and light output are obtained. In this way, the prepared scintillator glass simultaneously meets good internal quality, high transmittance, and light yield.

[0057] The functions and content selections of each component are as follows:

[0058] SiO2 is used as the network former of the glass to form the glass network framework. However, the applicant has found that when the content of SiO2 is greater than 27 wt%, the density of the glass will be significantly affected; when the content of SiO2 is less than 23 wt%, the degree of connection between silicon-oxygen tetrahedrons will become smaller, the stability of the glass will become worse, and it will be difficult to perform mechanical processing and optical processing. Therefore, the present invention selects the content of SiO2 in the scintillator glass to be between 23 and 27 wt%.

[0059] Al2O3 is a glass structure regulating oxide, and the level of its content affects the thermal expansion coefficient and chemical and thermal stability of the glass. However, when its content is greater than 3 wt%, it is difficult to melt the glass; when it is less than 1 wt%, the thermal stability of the glass is poor. For this reason, the present invention selects the content of Al2O3 to be between 1 and 3 wt%.

[0060] AlF3 is a glass structure regulating fluoride. The aluminum element is beneficial to improving the strength of the glass, and its melting point is lower than that of the relative oxide. When its content is greater than 3 wt%, it will cause phase separation of the glass; when it is less than 1 wt%, the thermal stability of the glass is poor. Therefore, the content of AlF3 in the present invention should be controlled within the range of 1 to 3 wt%.

[0061] B2O3 is an important component of glass. It can not only improve the stability of glass, but also increase the refractive index of glass, improve the luster of glass, and has good fluxing properties, accelerating the clarification of glass and reducing the crystallization ability of glass. However, when its content is greater than 10 wt%, phase separation will occur in the glass; when it is less than 7 wt%, it is difficult to melt the glass and it is difficult to form a clear glass melt. Therefore, in the present invention, the content of B2O3 in the scintillator glass is selected to be between 7 and 10 wt%.

[0062] SrO and CaO are network modifiers and enter the vacancies between the glass skeletons to adjust the viscosity and expansion coefficient of the glass. Since both of these substances are alkaline earth metal oxides, their functions are relatively similar. Through the research of the applicant, it is found that when the content of alkaline earth metal oxides is less than 20 wt% or higher than 28 wt%, the viscosity of the glass is not conducive to melting and stress release, causing processing difficulties, and thus affecting the preparation of large sizes in practical applications. Therefore, the content of alkaline earth metal oxides in the present invention should be controlled between 17 and 21 wt%.

[0063] Gd2O3 is a network modifier and belongs to heavy metal oxides, with a content in the range of 25 - 28 wt%. The metal element corresponding to this oxide has a large atomic number and a high density, which is beneficial to increasing the density of the scintillator glass. When the sum of the contents of these three substances is less than 25 wt%, the density of the glass is too small; when the content of these three substances is more than 28 wt%, the glass is prone to phase separation or ceramization, the temperature required for melting increases rapidly, the conditions required for melting are harsh, and the glass-forming performance is poor.

[0064] Ce in CeO2 is the luminescent center element of photoluminescence, and its content is in the range of 1 - 3 wt%. If the content of CeO2 is less than 1 wt%, the light yield will be insufficient, while if the content of CeO2 is higher than 3 wt%, self-quenching may occur, affecting the luminescence performance.

[0065] In some embodiments, the rare earth ion-doped borosilicate scintillator glass, by mass percentage, comprises:

[0066] silicon dioxide 25%; boron trioxide 8%; aluminum trioxide 1.5%; aluminum trifluoride 1.5%; strontium oxide 13%; calcium oxide 12.5%; gadolinium oxide 37%; cerium dioxide 1.5%.

[0067] According to some embodiments of the present invention, there is also provided a method for preparing the above rare earth ion-doped borosilicate scintillator glass, comprising the following steps:

[0068] Weigh each raw material according to the formula amount, mix them evenly to obtain a batch material, and weigh an organic reducing agent. Silicon element is introduced in the form of high-purity quartz sand, boron element is introduced in the form of boric acid, aluminum element is introduced in the form of alumina or aluminum fluoride, alkaline earth metal elements are introduced in the form of their carbonates, gadolinium and cerium elements are introduced in the form of their oxides. The reducing agent can be at least one of galactose, glucose and maltose. The function of the reducing agent is to prevent Ce(III) from being oxidized to Ce(IV), thereby reducing the luminescence performance. Its content is 1-3 wt% (accounting for the total weight of the batch material). When it is lower than 1 wt%, the reduction will be insufficient, resulting in the presence of Ce(IV) in the melted glass. When it is higher than 3 wt%, the improvement of the luminescence performance is not obvious, causing waste of the reducing agent.

[0069] In order to melt the scintillator glass, the crucible used is a high-purity quartz crucible to prevent impurity elements that may exist on the surface of the crucible from entering the glass system and affecting the luminescence performance of the glass. However, corundum crucibles or alumina crucibles are easily corroded by the glass melt, resulting in the components of the crucible entering the glass melt, causing the composition of the scintillator glass to be different from the preset one and affecting the relevant performance. Therefore, the crucible can only be a high-purity fused quartz crucible. The melting device used is a vacuum box-type electric furnace with a rotary vane pump and a diffusion pump. Its manufacturer is Yixing Zhongya Electric Furnace Equipment Co., Ltd. Its heating rate is adjustable. The melting furnace is heated at a heating rate of 4.5-5.5 °C / min. When the heating rate is lower than 4.5 °C / min, the melting time required will be too long, which may damage the reducing atmosphere during melting. When the heating rate is higher than 5.5 °C / min, it is easy to cause powdering of the batch material or explosion of the crucible.

[0070] Heat up to 1520 °C - 1550 °C for clarification for 3 - 5 hours. When the temperature is lower than 1520 °C or the reaction time is less than 3 hours, the reaction will be incomplete, and unreacted batch material will exist in the obtained glass. The melting temperature cannot be higher than 1550 °C, otherwise it is easy to cause the crucible to crack or the current of the heating electric furnace to be too high and malfunction. When the reaction time is greater than 5 hours, the reducing atmosphere will be damaged, which is not conducive to the high luminescence efficiency of the scintillator glass.

[0071] After the clarification is completed, turn off the heating control of the melting furnace to allow the melted glass melt to cool with the furnace. In order to ensure the elimination of thermal stress in the glass. After the melting furnace cools down to room temperature, close the intake valve of the melting furnace, turn on the rotary vane vacuum pump, turn on the pre-pump valve, and turn on the circulating water cooling to reduce the internal pressure of the melting furnace until the pressure reaches 80 - 120 Pa. The pressure cannot be reduced to less than 80 Pa, otherwise the glass melt will splash. When the pressure is greater than 120 Pa, heating cannot be carried out due to excessive pressure, otherwise too much high-temperature gas will be pumped into the rotary vane pump, causing damage to the pump.

[0072] After the pressure of the melting furnace drops to between 80 and 120 Pa, turn on the heating power supply of the melting furnace and let the melting furnace heat up at a heating rate of 4.5 to 5.5 °C / min. A heating rate lower than 4.5 °C / min is not conducive to the uniformity of the glass melt and the discharge of bubbles, while a heating rate higher than 5.5 °C / min is not conducive to adjusting the pressure parameters matching the temperature at any time.

[0073] After starting to heat up, turn on the diffusion pump heating. After 1 to 1.5 hours, turn on the diffusion pump. If the time is shorter than 1 hour, the diffusion pump is not preheated sufficiently and cannot fully exert its function. If it is longer than 1.5 hours, the glass melting time is too long, which is likely to cause the glass melt to splash. The diffusion pump reduces the internal pressure of the melting furnace until it drops to about 5 to 10 Pa. To ensure that the pressure during melting is around 5 to 10 Pa, the bubbles inside the glass can be fully removed. A pressure higher than 10 Pa is likely to cause the retention of bubbles, resulting in a decrease in refractive index and luminescence efficiency, while a pressure lower than 5 Pa will cause the glass melt not to move directionally, resulting in poor uniformity of the glass.

[0074] After the melting furnace heats up to 1520 °C to 1550 °C, carry out clarification for 1 to 3 hours. If it is less than 1 hour, the remaining bubbles cannot be completely removed, while if it is more than 3 hours, the improvement effect is not obvious; to protect the melting device, 1 to 1.5 hours after the clarification ends, turn off the power supply of the diffusion pump and the diffusion pump heating. If it is less than 1 hour, it is not conducive to heat preservation and is likely to cause the melting device and the crucible to crack. If it is more than 1.5 hours, it is not conducive to the annealing of the glass itself and the release of stress. Then turn off the power supply of the outlet valve and the rotary vane vacuum pump in sequence. After 2 to 2.5 hours, turn off the cooling circulating water. If it is less than 2 hours, the cooling is insufficient, and if it is more than 2.5 hours, the temperature will be too low. The melted glass is cooled and annealed in the furnace. After reaching room temperature, open the intake valve and take out the formed glass block to obtain the block-shaped scintillator glass.

[0075] During the process of glass melting, bubbles are likely to be generated. Stirring or prolonging the melting time is likely to damage the reducing atmosphere. In the above solution, the bubbles inside the glass are removed by the negative pressure method, reducing the defects of the glass, improving the homogenization of the glass while ensuring that the valence state of the luminescent center ions remains unchanged, thereby improving the transmittance and luminescence efficiency of the scintillator glass.

[0076] In order to facilitate processing, the formed glass block needs to be precisely annealed twice. It is placed in an annealing furnace at room temperature and heated to 600-650°C for 2-4 hours. The heating rate is controlled at 3-4°C / minute. If it is lower than 3°C / minute, the glass melts slowly and easily causes splashing of the liquid. If it is higher than 4°C / minute, it is easy to cause damage to the silicon-molybdenum rod of the heating device. Then it is kept warm for 2-4 hours, and then the power is turned off. The cooling time with the furnace is 16-18 hours. If it is lower than 16 hours, insufficient annealing is likely to cause the glass to burst. If it is higher than 18 hours, the whole process time will be prolonged. The rare earth ion-doped borosilicate scintillator glass is taken out from the furnace. If the heating and insulation time is less than 2 hours, the glass stress cannot be completely released, and there is a risk of bursting during mechanical processing; if the heating and insulation time is greater than 4 hours, the glass will soften. Temperatures below 600°C are not conducive to stress release, and temperatures above 650°C may cause glass phase separation.

[0077] For the convenience of testing, the block scintillator glass obtained above needs to be double-sided ground and polished using a 1M cerium oxide polishing solution (commercially available). The polishing is performed using a 1M cerium oxide polishing solution at a rotation speed of 500-600r / min. If the rotation speed is greater than 600r / min, the speed is too high and it is easy to cause the glass sample to burst; if the rotation speed is less than 500r / min, the speed is too low and it is difficult to achieve the corresponding polishing effect. The glass is then cut using a mechanical blade with a thickness of 0.2-0.25mm. If the blade is larger than 0.25mm, there will be more waste. If it is less than 0.2mm, it will be difficult to cut the glass and it will easily cause breakage and edge collapse. After cutting, standard test samples of 5mm×5mm×5mm or 5mm×5mm×3mm or 3mm×3mm×3mm are obtained for density testing, luminescence performance and decay time testing, and processed into

[0078] 15mm×15mm×2mm is used for transmittance test.

[0079] According to some embodiments of the present invention, a scintillator detector is provided, which includes a scintillator, wherein the scintillator is composed of the above-mentioned rare earth ion-doped borosilicate scintillator glass.

[0080] According to some embodiments of the present invention, a ring-shaped particle accelerator is further provided, and the ring-shaped particle accelerator includes the above-mentioned scintillator detector.

[0081] The present invention will be further described below in conjunction with specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0082] The melting methods, component compositions (wt%), and the dosages of the organic reducing agent (Glu) during the preparation of Examples 1-11 and Comparative Examples 1-5 of the present invention are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] The test performances of the scintillator glasses obtained in Examples 1-11 and the glasses obtained in Comparative Examples 1-5 were carried out in the following manner: The transmittance of the scintillator glass was measured using an ultraviolet spectrophotometer, the density of the scintillator glass was measured using a solid electronic densitometer, and 23 Na and 137 a Cs radiation source was used to irradiate the scintillating glass placed inside a silicon photomultiplier tube to measure the luminescence performance of the above-mentioned scintillator glass, as shown in Table 2 below.

[0087] The requirements for sample preparation for measuring the transmittance of the scintillator glass using an ultraviolet spectrophotometer are as follows:

[0088] The scintillator glass was cut using a mechanical blade with a thickness of 0.2 mm, ground and polished using a cerium oxide polishing solution (commercially available) with a concentration of 1 M to obtain a scintillator glass of standard size for performance testing, a glass sheet with dimensions of 15 mm × 15 mm × 2 mm, and both end faces were polished to a surface roughness Ra of less than 0.01 mm.

[0089] The glass sheet with the above-mentioned processed dimensions of 15 mm × 15 mm × 2 mm was subjected to an end-face penetration radiation resistance test using a γ beam, and the time when its light yield decreased to 90% of the original was recorded, and this time was recorded to characterize the radiation resistance performance of the glass.

[0090] The test curve of the transmittance of Example 1 is as shown in the appendix Figure 1 shown, and it can be seen from Figure 1 that the average transmittance at wavelengths of 300-600 nm is above 84%. The good transmittance ensures that the photons excited after the scintillator glass absorbs high-energy rays can pass through the glass, and then transmit the photon signal, ensuring a good light yield.

[0091] The test conditions for measuring the transmittance of the scintillator glass using an ultraviolet spectrophotometer and the luminescence performance and decay time of the 23Na and 137Cs radiation sources irradiating the silicon photomultiplier tube are as follows:

[0092] Sample preparation requirements: The scintillator glass is processed by mechanical cutting, grinding, and polishing to obtain a scintillator glass for density and optical property testing, in the shape of a cube with dimensions of 5mm × 5mm × 3mm. The light incident end face and the photon exit end face of the radiation source are polished.

[0093] With 23 Na and 137 The luminescence performance of the scintillator glass of Example 1 irradiated with Cs radiation sources is as Figure 2 shown. It can be seen from Figure 2 that at an energy of 5500 MeV, a relatively large number of photons are generated, which can meet the performance requirements of the scintillator glass.

[0094] Table 2

[0095]

[0096] From the data in Table 1 and Table 2, it can be seen that the scintillator glasses of Examples 1 - 11 of the present invention have the characteristics of high transmittance, high light yield, and high density. In Comparative Example 1, after reducing the gadolinium oxide content to 28%, the density of the scintillator glass decreased significantly, not meeting the usage requirements. In Comparative Example 2, after reducing the doping ratio of the luminescence center element to 0.5%, the luminescence performance of the scintillator glass decreased significantly. In Comparative Example 3, the use of the reducing agent was reduced, resulting in a change in the valence state of the luminescence center ions and a decrease in the light yield. In Comparative Example 4, the glass was only melted once under normal pressure without secondary melting under negative pressure conditions, resulting in poor internal quality of the glass, defects such as bubbles, a decrease in transmittance, and a deterioration in light yield. In Comparative Example 5, no organic reducing agent was used, resulting in a higher proportion of oxidation of the luminescence center ions and a sudden drop in the light yield. For the scintillator glass samples provided in Examples 1 - 11 above, the above tests were carried out, and the results showed that all indicators reached a relatively high level, meeting the actual application requirements.

[0097] The scintillator glass with dimensions of 15mm × 15mm × 2mm in Example 1 was arranged in a cube array of 450mm × 450mm × 2mm with 30 pieces in each group. This cube array forms part of a scintillator detector, which can be applied to a circular particle accelerator to detect high - energy particles, achieving the detection of high - energy particle γ - rays. Its light yield reaches 1300 ph / MeV, the decay time is 110 s, and it can work continuously for 200 h.

[0098] In the description of the present invention, a large number of specific details are set forth. However, it can be understood that the embodiments of the present invention can be practiced without these specific details. In some embodiments, well - known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0099] In addition, it should be noted that, for each of the specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination manners.

[0100] In addition, any arbitrary combination can also be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

[0101] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A rare earth ion-doped borosilicate scintillator glass, characterized in that, By mass percentage, it contains: Silica 23 - 27%; Boron trioxide 7 - 10%; Aluminum fluoride 1 - 3%; Aluminum oxide 1 - 3%; Strontium oxide 11 - 15%; Calcium oxide 9 - 13%; Gadolinium oxide 35 - 38%; Cerium dioxide 1 - 3%; The rare earth ion - doped borosilicate scintillator glass further includes an organic reducing agent by weight percentage; the organic reducing agent accounts for 1% - 3% of the total weight of the components of the rare earth ion - doped borosilicate scintillator glass except the organic reducing agent; the organic reducing agent is glucose and / or galactose and / or maltose; The rare earth ion - doped borosilicate scintillator glass is prepared by the following steps: S1 Weigh 23 - 27% of silica, 7 - 10% of boron trioxide, 1 - 3% of aluminum fluoride, 1 - 3% of aluminum oxide, 11 - 15% of strontium oxide, 9 - 13% of calcium oxide, 35 - 38% of gadolinium oxide, and 1 - 3% of cerium dioxide in sequence by mass percentage, mix them evenly to obtain a batch, and weigh an organic reducing agent accounting for 1 wt% - 3% of the total weight of the batch and add it to the batch; S2 After the feeding is completed, heat the batch containing the organic reducing agent at a heating rate of 4.5 - 5.5 °C / min, heat up to 1520 °C - 1550 °C, and then clarify for 3 - 5 hours; S3 After the clarification is completed, cool the molten glass to room temperature, then reduce the air pressure to 80 - 120 Pa; then heat at a heating rate of 4.5 - 5.5 °C / min; S4 After starting to heat, heat for 1 - 1.5 hours, then reduce the air pressure until it is reduced to 5 - 10 Pa; heat up to 1520 °C - 1550 °C and then clarify the glass liquid for 1 - 3 hours; S5 1 - 1.5 hours after the clarification is completed, stop heating, and after 2 - 2.5 hours, cool and anneal the molten glass until it is cooled to room temperature to obtain the rare earth ion - doped borosilicate scintillator glass.

2. The rare earth ion-doped borosilicate scintillator glass according to claim 1, wherein The average transmittance of the rare earth ion - doped borosilicate scintillator glass at 300 - 600 nm is 84% - 87%.

3. The rare earth ion-doped borosilicate scintillator glass according to claim 1, wherein The light yield of the rare earth ion - doped borosilicate scintillator glass is 1206 - 1296 ph / MeV.

4. The rare earth ion-doped borosilicate scintillator glass according to claim 1, wherein The density of the rare earth ion-doped borosilicate scintillation glass is 5.81~5.96 g / cm 3 .

5. The rare earth ion-doped borosilicate scintillator glass according to claim 1, wherein The decay time of the rare earth ion - doped borosilicate scintillator glass is 100 - 128 ns; the radiation - resistant time of the rare earth ion - doped borosilicate scintillator glass is 173 - 198 h.

6. A method for preparing a rare earth ion-doped borosilicate scintillator glass, characterized in that, Including the following steps: S1 Weigh 23 - 27% of silica, 7 - 10% of boron trioxide, 1 - 3% of aluminum fluoride, 1 - 3% of aluminum oxide, 11 - 15% of strontium oxide, 9 - 13% of calcium oxide, 35 - 38% of gadolinium oxide, and 1 - 3% of cerium dioxide in sequence by mass percentage, mix them evenly to obtain a batch, and weigh an organic reducing agent accounting for 1 wt% - 3% of the total weight of the batch and add it to the batch; the organic reducing agent is selected from at least one of maltose, galactose, and glucose; After the feeding in S2 is completed, the batch containing the organic reducing agent is heated at a heating rate of 4.5 - 5.5 °C / min until the temperature reaches 1520 °C - 1550 °C, and then clarified for 3 - 5 hours. After the clarification in S3 is completed, the melted glass liquid is cooled to room temperature, and then the air pressure is reduced to 80 - 120 Pa; thereafter, it is heated at a heating rate of 4.5 - 5.5 °C / min. After the heating starts in S4, the pressure is reduced 1 - 1.5 hours later until it is reduced to 5 - 10 Pa; when the temperature reaches 1520 °C - 1550 °C, the glass liquid is clarified for 1 - 3 hours. 1 - 1.5 hours after the clarification in S5 is completed, the heating is stopped, and 2 - 2.5 hours later, the melted glass is cooled and annealed until it is cooled to room temperature, and then the rare earth ion - doped borosilicate scintillator glass is obtained.

7. The preparation method of the rare earth ion-doped borosilicate scintillator glass according to claim 6, characterized in that, Step S5 also includes a step of precisely annealing the formed glass block after cooling to room temperature.

8. The preparation method of the rare earth ion-doped borosilicate scintillator glass according to claim 7, characterized in that, The precise secondary annealing includes: heating the formed glass block from room temperature to 600 - 650 °C at a heating rate of 3 - 4 °C / min for 2 - 4 hours, then holding for 2 - 4 hours, and then cutting off the power supply to let the glass cool to room temperature with the furnace, and the rare earth ion - doped borosilicate scintillator glass is obtained.

9. A scintillator detector, characterized in that, It includes a scintillator, and the scintillator is composed of the rare earth ion - doped borosilicate scintillator glass according to any one of claims 1 - 5.

10. A circular particle accelerator, characterized in that, The annular particle accelerator includes the scintillator detector according to claim 9.

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