A lithium tetraborate-zinc scintillation glass microcrystalline, its preparation method and application

Abstract

The present invention discloses a lithium tetraborate-zinc tantalate scintillating glass-ceramics and its preparation method and application. The chemical composition expression of the borate scintillating glass-ceramics of the present invention is Li2B4O7-x at% Zn3Ta2O8, where 0 < x ≤ 20, and the proportion of the microcrystalline phase Zn3Ta2O8 doping in the overall borate scintillating glass-ceramics is 0 to 20 at%. The scintillating luminescent material in the present invention is synthesized by the high-temperature melting method, is stable in air, has a safe and simple process, and is easy to control. Under X-ray excitation, the light yield of the scintillating glass-ceramics of the present invention is 455 to 3198 ph. / MeV. Among them, the light yield of Li2B4O7-5 at% Zn3Ta2O8 is the highest, which is 35.5% of the BGO crystal, and it is a glass-ceramic scintillator with a high light yield that emits light by means of Zn3Ta2O8.

Description

Technical Field

[0001] This invention relates to a lithium tetraborate-zinc tantalate (Li2B4O7-Zn3Ta2O8) scintillation microcrystalline glass, its preparation method and application, belonging to the field of scintillation glass technology. Background Art

[0002] A scintillator is a photoconductive luminescent material that converts the ionization energy of high-energy photons (X-rays, gamma rays) or particles (hadrons, electrons, protons, alpha particles, etc.) into ultraviolet / visible light; it is an energy converter. Scintillators are widely used in high-energy physics experiments, nuclear medicine imaging, industrial non-destructive testing, security inspection, environmental monitoring and exploration, and astronomical observation. Scintillators have evolved from the earliest discovered CaWO4 to the commercially used NaI:Tl. + and Bi4Ge3O 12 The types of scintillation single crystals are constantly being expanded and enriched, mainly including single crystals, glass, transparent ceramics, polymers, quantum dots, gases, and various composite materials.

[0003] Glass scintillators are a crucial class of scintillator materials, serving as an important complement to other scintillator materials such as crystals, organic plastics, and liquids. They offer advantages in areas such as continuously tunable composition design, simpler large-scale fabrication processes, superior cutting and hot bending techniques, and mature fiber drawing processes. These advantages extend to large-volume detectors, fiber optic imaging, position resolution, and micro-area dose detection. After heat treatment, doped glass forms a nanoscale microcrystalline phase. Because its size is smaller than the wavelength of visible light, it reduces light scattering losses easily caused by crystal particles. Therefore, the combination of glass and the microcrystalline phase can effectively improve scintillator performance.

[0004] Li₂B₄O₇ glass has excellent optical properties and is widely used in photoacoustic electronic devices, piezoelectric transmission devices, and nonlinear optical materials. It has high viscosity in the molten state and can be doped with other oxides in higher concentrations to obtain various properties.

[0005] Zn3Ta2O8 material belongs to the monoclinic crystal system. Under the excitation of high-energy particles or radiation, self-trapped excitons Ta 4+ -O - The emitted light at 410 nm falls within the high-sensitivity detection band of commercial photomultiplier tubes. XEL spectroscopy analysis of Zn3Ta2O8 microcrystalline powder, compared with the intensity of the XEL spectrum of Mg4Ta2O9 microcrystalline powder, estimated the X-ray scintillation yield of Zn3Ta2O8 crystal to be 26000 ph. / MeV. It exhibits rapid decay time, with 20% decaying at 200 ns and 80% at 1100 ns. Furthermore, it has a high density of 7.14 g / cm³. 3, which has a strong ability to block rays, is a new type of scintillation material with excellent performance. However, the melting point of the Zn3Ta2O8 material is 1700 °C. When the temperature reaches 1300 °C and above, during growth under atmospheric pressure, a large amount of the ZnO component decomposes and volatilizes, causing the grown crystal to deviate from the stoichiometric ratio and greatly affecting the scintillation performance. In order to inhibit the volatilization and decomposition of ZnO, it is necessary to grow rapidly in a high-pressure oxygen atmosphere. In 2022, Ryuga Yajima et al. published an article titled "Growth of Zn3Ta2O8 crystals scintillator by a novel melt growth technique named shielded arc melting method", introducing a crystal growth method of arc plasma heating using a Ta metal shield (Shield Ta Metal Box Indirectly Heated by Arc Plasma). The grown crystals contain ZnO heterophase and do not completely solve the problem of ZnO volatilization and decomposition. The size is Φ5mm×1mm, the crystallization quality is poor, colorless and translucent, containing a large number of cracks, so the scintillation performance is poor. Under the excitation of 662 keV gamma rays, the light yield is only 4700 ph. / MeV.

[0006] Other crystal growth methods, such as the commonly used pulling method and micro-pulling method, require an Ir crucible and must be grown under a high-pressure protective atmosphere, which obviously cannot meet the atmosphere requirements for the growth of Zn3Ta2O8 crystals. Although the commonly used floating zone method does not require a crucible, the volatilized ZnO will adhere to the inner wall of the quartz tube, blocking the heating and focusing path of infrared light. The shell melting method does not require a crucible, but the medium- and high-frequency induction coils are made of metal materials and are also not suitable for growth in a high-pressure oxygen atmosphere. It can be seen that it is extremely difficult to grow high-quality stoichiometric Zn3Ta2O8 single crystals. Summary of the Invention

[0007] The technical problem solved by the present invention is: how to obtain a scintillating glass-ceramic that emits light with a high light yield and has a stoichiometric Zn3Ta2O8.

[0008] To solve the above technical problem, the present invention provides a lithium tetraborate-zinc tantalate scintillating glass-ceramic, whose chemical composition expression is Li2B4O7 - x at% Zn3Ta2O8, where 0 < x ≤ 20, Li2B4O7 is the matrix, and Zn3Ta2O8 is the microcrystalline phase; that is, the proportion of the doped microcrystalline phase Zn3Ta2O8 in the whole scintillating glass-ceramic is 0 - 20 at%.

[0009] Preferably, the light yield of the borate scintillating glass-ceramic is 455 - 3198 ph. / MeV.

[0010] The present invention also provides a method for preparing the above-mentioned lithium tetraborate-zinc tantalate scintillation microcrystalline glass, comprising:

[0011] Step 1: Weigh high-purity powder ZnO (99.99%) and Ta2O5 (99.99%) at a molar ratio of 3.12:1, grind the raw materials thoroughly in an agate mortar, and pre-calcine them in a muffle furnace to synthesize pure phase Zn3Ta2O8 powder;

[0012] Step 2: Weigh the raw materials high-purity Li2B4O7 (99.99%) and Zn3Ta2O8 powder obtained in Step 1 according to the stoichiometric ratio. Grind the raw materials thoroughly in an agate mortar. Pour the ground raw materials into a platinum crucible and then place it in a glass furnace for melting treatment to obtain a uniform glass liquid. Subsequently, rapidly cool the glass liquid to obtain cylindrical scintillation glass-ceramics.

[0013] Preferably, the preheating temperature in step 1 is 1200℃ and the holding time is 10h.

[0014] Preferably, the melting treatment in step 2 is carried out at a temperature of 1100°C for 4 hours.

[0015] This invention also provides the application of lithium tetraborate-zinc tantalate scintillation glass in nuclear medicine imaging, security inspection, radiation monitoring, detection, identification and quantitative analysis of high-energy particles.

[0016] This invention uses Li₂B₄O₇ glass as a matrix, leveraging its high transmittance in the near-infrared and visible / ultraviolet regions (350–1400 nm), excellent optical properties, stable physicochemical properties, and low melting temperature. LBO-x at% Zn₃Ta₂O₈ glass scintillators are prepared by melting with different molar ratios of Zn₃Ta₂O₈. Through scintillation emission of Zn₃Ta₂O₈ microcrystals with stoichiometric ratios, a high-yield Zn₃Ta₂O₈-activated Li₂B₄O₇ scintillator glass is obtained, which can be applied in fields such as nuclear medicine imaging, security inspection, environmental monitoring, high-energy particle detection and identification, and quantitative analysis.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The scintillation glass of the present invention has high transmittance in the Zn3Ta2O8 emission band, and can fully transmit photons emitted by the scintillation emission of pure phase Zn3Ta2O8 microcrystals with equal stoichiometry;

[0019] 2. The scintillation glass of the present invention has a high light yield, wherein the light yield of the Li2B4O7-5at%Zn3Ta2O8 scintillation glass under X-ray excitation is equivalent to that of BGO (i.e., Bi3Ge5O). 12The crystal has a density of 35.5% and a value of 3198 ph. / MeV, making it an outstanding performer in the field of scintillation glass.

[0020] 3. The scintillation microcrystalline glass of the present invention is colorless, transparent, crack-free, and has good uniformity. It can be cast into various shapes and is easy to achieve large-scale, low-cost, and large-size industrial production. It has broad application prospects and significant practical significance in nuclear medicine imaging, security inspection, radiation monitoring, detection, identification, and quantitative analysis of high-energy particles. Attached Figure Description

[0021] Figure 1 Images of Li2B4O7-x at%Zn3Ta2O8 scintillation microcrystalline glass prepared in Examples 1-5;

[0022] Figure 2 X-ray diffraction patterns of the scintillation glass-ceramics prepared in Examples 1-3;

[0023] Figure 3 The emission spectrum of Li2B4O7-1at%Zn3Ta2O8 scintillation microcrystalline glass was measured under X-ray excitation;

[0024] Figure 4 The emission spectrum of Li2B4O7-5at%Zn3Ta2O8 scintillation microcrystalline glass was measured under X-ray excitation;

[0025] Figure 5 The emission spectrum of Li2B4O7-10at%Zn3Ta2O8 scintillation microcrystalline glass was measured under X-ray excitation. Detailed Implementation

[0026] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0027] In the following examples, all raw materials and reagents used are commercially available products.

[0028] Example 1

[0029] The preparation method of Li2B4O7-1at%Zn3Ta2O8 scintillation microcrystalline glass includes the following steps:

[0030] High-purity ZnO (99.99%) and Ta₂O₅ (99.99%) powders were weighed at a molar ratio of 3.12:1 and ground thoroughly in an agate mortar for 2 hours. The powders were then pre-calcined at 1200℃ for 10 hours in a high-temperature muffle furnace to synthesize pure-phase Zn₃Ta₂O₈ powder. Precisely weighed glass raw materials Li₂B₄O₇ (99.99%) and Zn₃Ta₂O₈, calculated according to stoichiometric ratios, were ground thoroughly in an agate mortar for 3 hours. The ground materials were then poured into a platinum crucible and placed in a high-temperature glass furnace at 1100℃ for 4 hours to obtain a homogeneous glass melt. The glass melt was then rapidly cooled to obtain cylindrical scintillation glass-ceramics. Figure 1 As shown, the Li2B4O7-1at%Zn3Ta2O8 scintillation microcrystalline glass is colorless, transparent, and crack-free, with a diameter of approximately 1 inch.

[0031] The X-ray diffraction peaks of the glass are as follows Figure 2 The diffraction pattern of Li₂B₄O₇-1at%Zn₃Ta₂O₈ is shown in the figure. As can be seen from the curves, all diffraction peaks correspond to the standard sample Li₂B₄O₇. Figure 3 The emission spectrum of Li2B4O7-1at%Zn3Ta2O8 at 30keV X-ray excitation shows that its emission wavelength is 506nm, the luminescence intensity is 5.1% of that of BGO crystal, and the light yield is 455ph / MeV.

[0032] Example 2

[0033] The preparation method of Li2B4O7-5at%Zn3Ta2O8 scintillation microcrystalline glass includes the following steps:

[0034] High-purity ZnO (99.99%) and Ta₂O₅ (99.99%) powders were weighed at a molar ratio of 3.12:1 and ground thoroughly in an agate mortar for 2 hours. The powders were then pre-calcined at 1200℃ for 10 hours in a high-temperature muffle furnace to synthesize pure-phase Zn₃Ta₂O₈ powder. Precisely weighed glass raw materials Li₂B₄O₇ (99.99%) and Zn₃Ta₂O₈, calculated according to stoichiometric ratios, were ground thoroughly in an agate mortar for 3 hours. The ground materials were then poured into a platinum crucible and placed in a high-temperature glass furnace at 1100℃ for 4 hours to obtain a homogeneous glass melt. The glass melt was then rapidly cooled to obtain cylindrical scintillation glass-ceramics. Figure 1 As shown, the Li2B4O7-5at%Zn3Ta2O8 scintillation microcrystalline glass is colorless, transparent, and crack-free, with a diameter of approximately 1 inch.

[0035] The X-ray diffraction peaks of the glass are as follows Figure 2 The diffraction pattern of Li₂B₄O₇-5at%Zn₃Ta₂O₈ is shown in the figure. As can be seen from the curves, all diffraction peaks correspond to the standard sample Li₂B₄O₇. Figure 4 The emission spectrum of Li2B4O7-5at%Zn3Ta2O8 at 30keV X-ray excitation shows that its emission wavelength is 417nm, the luminescence intensity is 35.5% of that of BGO crystal, and the light yield is 3198ph / MeV.

[0036] Example 3

[0037] The preparation method of Li2B4O7-10at%Zn3Ta2O8 scintillation microcrystalline glass includes the following steps:

[0038] High-purity ZnO (99.99%) and Ta₂O₅ (99.99%) powders were weighed at a molar ratio of 3.12:1 and ground thoroughly in an agate mortar for 2 hours. The powders were then pre-calcined at 1200℃ for 10 hours in a high-temperature muffle furnace to synthesize pure-phase Zn₃Ta₂O₈ powder. Precisely weighed glass raw materials Li₂B₄O₇ (99.99%) and Zn₃Ta₂O₈, calculated according to stoichiometric ratios, were ground thoroughly in an agate mortar for 3 hours. The ground materials were then poured into a platinum crucible and placed in a high-temperature glass furnace at 1100℃ for 4 hours to obtain a homogeneous glass melt. The glass melt was then rapidly cooled to obtain cylindrical scintillation glass-ceramics. Figure 1 As shown, the Li2B4O7-10at%Zn3Ta2O8 scintillation microcrystalline glass is colorless, transparent, and crack-free, with a diameter of approximately 1 inch.

[0039] The X-ray diffraction peaks of the glass are as follows Figure 2 The diffraction pattern of Li₂B₄O₇-10at%Zn₃Ta₂O₈ is shown in the figure. As can be seen from the curves, all diffraction peaks correspond to the standard sample Li₂B₄O₇. Figure 5 The X-ray emission spectrum of Li2B4O7-10at%Zn3Ta2O8 at 30keV shows that its emission wavelength is 426nm, the luminescence intensity is 32.0% of that of BGO crystal, and the light yield is 2884ph / MeV.

[0040] Example 4

[0041] The preparation method of Li2B4O7-15at%Zn3Ta2O8 scintillation microcrystalline glass includes the following steps:

[0042] High-purity ZnO (99.99%) and Ta₂O₅ (99.99%) powders were weighed at a molar ratio of 3.12:1 and ground thoroughly in an agate mortar for 2 hours. The powders were then pre-calcined at 1200℃ for 10 hours in a high-temperature muffle furnace to synthesize pure-phase Zn₃Ta₂O₈ powder. Precisely weighed glass raw materials Li₂B₄O₇ (99.99%) and Zn₃Ta₂O₈, calculated according to stoichiometric ratios, were ground thoroughly in an agate mortar for 3 hours. The ground materials were then poured into a platinum crucible and placed in a high-temperature glass furnace at 1100℃ for 4 hours to obtain a homogeneous glass melt. The glass melt was then rapidly cooled to obtain cylindrical scintillation glass-ceramics. Figure 1 As shown, the Li2B4O7-15at%Zn3Ta2O8 scintillation microcrystalline glass is colorless, transparent, and crack-free, with a diameter of approximately 1 inch.

[0043] Example 5

[0044] The preparation method of Li2B4O7-20at%Zn3Ta2O8 scintillation microcrystalline glass includes the following steps:

[0045] High-purity ZnO (99.99%) and Ta₂O₅ (99.99%) powders were weighed at a molar ratio of 3.12:1 and ground thoroughly in an agate mortar for 2 hours. The powders were then pre-calcined at 1200℃ for 10 hours in a high-temperature muffle furnace to synthesize pure-phase Zn₃Ta₂O₈ powder. Precisely weighed glass raw materials Li₂B₄O₇ (99.99%) and Zn₃Ta₂O₈, calculated according to stoichiometric ratios, were ground thoroughly in an agate mortar for 3 hours. The ground materials were then poured into a platinum crucible and placed in a high-temperature glass furnace at 1100℃ for 4 hours to obtain a homogeneous glass melt. The glass melt was then rapidly cooled to obtain cylindrical scintillation glass-ceramics. Figure 1 As shown, the Li2B4O7-20at%Zn3Ta2O8 scintillation microcrystalline glass is colorless, transparent, and crack-free, with a diameter of approximately 1 inch.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make several improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A lithium tetraborate-zinc tantalate scintillation microcrystalline glass, characterized in that, Its chemical composition expression is Li2B4O7 - x at% Zn3Ta2O8, where 0 < x ≤ 20, Li2B4O7 is the matrix, and Zn3Ta2O8 is the microcrystalline phase.

2. The lithium tetraborate-zinc tantalate scintillation glass as described in claim 1, characterized in that, The light yield of the lithium tetraborate - zinc tantalate scintillating glass - ceramics is 455 - 3198 ph / MeV.

3. The method for preparing lithium tetraborate-zinc scintillation glass crystal according to claim 1 or 2, characterized in that, Including: Step 1: Weigh high - purity powders ZnO and Ta2O5 according to a molar ratio of 3.12:1, fully grind the raw materials in an agate mortar, and pre - sinter to synthesize pure - phase Zn3Ta2O8 powder in a muffle furnace. Step 2: Weigh the raw materials high - purity Li2B4O7 and the Zn3Ta2O8 powder obtained in Step 1 according to the stoichiometric ratio, fully grind the raw materials in an agate mortar, pour the well - ground raw materials into a platinum crucible, then put it into a glass furnace for melting treatment to obtain a homogeneous glass melt, and then rapidly cool the glass melt to obtain cylindrical scintillating glass - ceramics.

4. The method for preparing lithium tetraborate-zinc scintillation glass as described in claim 3, characterized in that, In Step 1, the pre - sintering temperature is 1200 °C and the holding time is 10 h.

5. The method for preparing lithium tetraborate-zinc scintillation glass as described in claim 3, characterized in that, In Step 2, the melting treatment temperature is 1100 °C and the time is 4 h.

6. Application of the lithium tetraborate - zinc tantalate scintillating glass - ceramics according to Claim 1 or 2 in nuclear medicine imaging, security inspection, or detection of high - energy particles.

7. Application of the lithium tetraborate - zinc tantalate scintillating glass - ceramics according to Claim 1 or 2 in radiation monitoring.

8. Application of the lithium tetraborate - zinc tantalate scintillating glass - ceramics according to Claim 1 or 2 in discrimination or quantitative analysis.

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