A multi-rare earth ion doped bromide microcrystalline glass scintillator and a preparation method thereof

Abstract

This invention relates to a multi-rare-earth ion-doped bromide microcrystalline glass scintillator and its preparation method. It is prepared from the following raw materials in molar percentages: 30-50 mol% ZnBr2, 20-30 mol% ABr, 10-25 mol% PbBr2, 10-20 mol% LaBr3, and 0.5-2 mol% rare-earth bromides. The multi-ion-doped halide microcrystalline glass prepared using the method of this invention can achieve in-situ precipitation of LaBr3; simultaneously, among the doped rare-earth ions, Ce... 3+ With Pr 3+ Energy transfer exists, especially Ce. 3+ For Pr 3+ Ion luminescence exhibits excellent sensitization effects; therefore, the introduction of these rare earth ions helps improve the light output, energy resolution, and temporal resolution of the glass-ceramic. This glass-ceramic has a low melting temperature, a simple preparation process, low production cost, and good mechanical properties and stability.

Description

Technical Field

[0001] This invention relates to the field of electrodeless light-emitting materials, and particularly to a bromide microcrystalline glass scintillator doped with multiple rare earth ions and its preparation method. Background Technology

[0002] X-ray detection is a technique that uses X-rays for imaging and analysis. X-rays are characterized by high energy, short wavelength, and strong penetrating power, allowing them to penetrate non-metallic materials and be absorbed by atoms within the matter. By measuring the intensity, wavelength, and duration of X-rays, information about the structure and composition of matter can be obtained. X-ray detection is closely related to scintillators. The principle of a scintillator is to utilize its physical properties, such as high refractive index and high scattering cross-section, to scatter and amplify incident X-rays, thereby enabling the detection of X-ray signals. Besides its use in X-ray detectors, scintillators can also be used in other fields, such as nuclear medicine imaging and particle physics experiments. In nuclear medicine imaging, scintillators can generate fluorescence signals through the radiation of radioactive isotopes, allowing observation of the internal structure and function of the human body. In particle physics experiments, scintillators can be used to generate high-energy particle beams and detect neutrinos.

[0003] Cerium-doped lanthanum bromide crystal (LaBr3:Ce) has attracted considerable research attention due to its excellent scintillation properties. This crystal exhibits a light output of 78000 Ph / MeV, a fast decay time of 30 ns, and a light density of 5.1 g / cm³. 3 With its higher density, LaBr3:Ce crystal exhibits significantly stronger absorption capacity for high-performance radiation than NaI:Tl crystals, while also posing a lower environmental pollution risk. Therefore, LaBr3:Ce crystals have become representative of high-output, fast-decay scintillation crystals, and are expected to find widespread application in medical instruments, security inspections, and oil well detection. However, this crystal is difficult to grow, its components are volatile, and it readily reacts with oxygen and water, making it prone to cracking. This results in low device yields, particularly for large-size devices, leading to high costs. Most grown devices are cylindrical, and the deliquescent nature of the crystal makes the fabrication of irregularly shaped devices difficult. Furthermore, multi-ion doping is not easily performed in the crystalline state, especially with ions whose atomic radii differ significantly from the crystal's. Additionally, the experimental cycle for ion doping during crystal growth is extremely long. Therefore, there is an urgent need for a LaBr3 scintillator that can replace the traditional crystalline state.

[0004] Glass-ceramics, as a novel optical material, possess both the excellent optical properties of crystalline materials and the advantages of glass materials, such as simple preparation, low cost, and stable performance. Many glass-ceramic scintillator materials have been reported in recent years, but all are based on Ce-doped glass. 3+ 、Tb 3+ Eu 3+Fluoride or oxide glasses containing heavy metal ions present challenges. Fluoride glasses, due to their large band gap and low crystallinity, struggle to achieve high light yields. Oxide glasses, on the other hand, face the challenge of high melting temperatures and are prone to absorption of scintillating light by the glass matrix, affecting the system's light output. Therefore, developing a microcrystalline glass scintillator with short fluorescence lifetime and strong scintillating light is of great significance for practical applications.

[0005] In recent years, nanocrystalline composite glass scintillators have been extensively studied. The invention patent CN103951258A published a method for preparing LaBr3 glass microcrystalline glass, but it uses the preparation method of fluoride glass. Due to its large band gap and low crystallinity, fluoride glass is difficult to achieve high light yield. Moreover, the patent only involves one doping ion, and the glass raw materials lack network ions. In large-size glass, stress is easily generated, and the glass porosity is high. Alkali metal bromides act as network modifiers. Summary of the Invention

[0006] This invention relates to a multi-rare-earth ion-doped bromide microcrystalline glass scintillator and its preparation method. The multi-rare-earth ion-doped bromide microcrystalline glass scintillator obtained by this invention has high fluorescence intensity. Moreover, the method of this invention has a short growth cycle and can grow large-size glass scintillators that are not prone to cracking, have high transmittance and few defects, thereby facilitating the fabrication of large-size devices. Since the prepared device is a microcrystalline glass scintillator, it can be used to fabricate devices of various shapes.

[0007] This invention is achieved through the following technical solution:

[0008] A rare earth ion-doped bromide microcrystalline glass scintillator is prepared from the following raw materials in molar percentages: 30-50 mol% ZnBr2, 20-30 mol% ABr, 10-25 mol% PbBr2, 10-20 mol% LaBr3 and 0.5-2 mol% rare earth bromides.

[0009] Specifically, the rare earth bromide is formed by mixing CeBr3 and PrBr3 in any proportion.

[0010] Specifically, the ABr is one or a mixture of two or more of NaBr, KBr, and CsBr in any proportion.

[0011] This invention relates to a multi-rare-earth ion-doped halide microcrystalline glass scintillator, which uses a metal bromide as a glass substrate. Through high-temperature heat treatment, LaBr3 microcrystals are precipitated in situ within the glass, resulting in a multi-ion-doped microcrystalline glass. The glass's structural network consists of interconnected [ZnBr4] tetrahedra, with the alkali metal bromide acting as a network modifier. Energy transfer occurs via Ce.3+ Pr 3+ As a luminescent center, it is incorporated into the crystal phase, especially Ce 3+ For Pr 3+ Ion luminescence has a good sensitizing effect. Zinc bromide acts as an excellent glass forming agent and improves the transmittance of glass.

[0012] The method for preparing the multi-rare-earth ion-doped bromide microcrystalline glass scintillator includes the following steps:

[0013] (1) Ingredient grinding: Grind the weighed ZnBr2, ABr, PbBr2, LaBr3 and rare earth bromide together for 20-30 minutes until they are mixed evenly;

[0014] (2) Melting: Pour the material after batching and grinding in step (1) into a crucible, and then put it into a lifting furnace with argon protective gas. Gradually raise the temperature to 400-500℃ and keep it at 400-500℃ for 1-2 hours to form glass melt.

[0015] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a mold preheated to 100℃-150℃, and then let it cool naturally until the glass melt solidifies into a glass body;

[0016] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 300-380℃ for annealing for 8-10 hours to obtain the bromide microcrystalline glass scintillator doped with rare earth ions.

[0017] Specifically, the crucible used for melting in step (2) is an alumina crucible.

[0018] Specifically, step (3) involves forming a copper mold for heat treatment.

[0019] Specifically, in step (1), the ingredients are ground using an agate mortar and pestle.

[0020] Specifically, the heating rate during melting in step (2) is 50-100 degrees Celsius per hour. During the melting process, the heating rate and holding time need to be controlled to ensure that the raw materials are fully melted and a uniform melt is formed. At the same time, the temperature and chemical composition of the melt need to be checked regularly to ensure the stability and consistency of the melting process.

[0021] During the annealing process, it is necessary to control the furnace temperature and holding time in order to eliminate stress and defects in the glass, and at the same time precipitate LaBr3 microcrystals in situ.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] The multi-rare-earth ion-doped bromide microcrystalline glass scintillator of the present invention introduces various rare-earth ions into the lanthanum bromide crystal phase. Compared with single doping, Ce... 3+ With Pr 3+ Energy transfer exists between them, and Ce 3+ For Pr 3+ Ion luminescence has a good sensitizing effect and can improve the fluorescence intensity of the device.

[0024] The glass prepared by this method has a lower melting temperature, which is beneficial for production and manufacturing.

[0025] The microcrystalline glass of this invention can effectively prevent the decomposition and valence change of lanthanum bromide, which is beneficial to improving scintillation performance;

[0026] The microcrystalline glass of this invention has a suitable temperature range and a simple manufacturing method, enabling the mass production of large-size devices. Attached Figure Description

[0027] Figure 1 This is a photograph of the bromide microcrystalline glass scintillator doped with multiple rare earth ions prepared in Example 1.

[0028] Figure 2 This is a transmittance curve of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in Example 1.

[0029] Figure 3 This is a fluorescence spectrum curve of the bromide microcrystalline glass scintillator doped with multiple rare earth ions prepared in Example 1.

[0030] Figure 4 This is a photograph of the bromide microcrystalline glass scintillator doped with multiple rare earth ions prepared in Example 2.

[0031] Figure 5 This is the fluorescence spectrum of the bromide microcrystalline glass scintillator doped with rare earth ions prepared in Comparative Example 1.

[0032] Figure 6 This is the fluorescence spectrum of the bromide microcrystalline glass scintillator doped with rare earth ions prepared in Comparative Example 2.

[0033] Figure 7 This is the fluorescence spectrum of the bromide microcrystalline glass scintillator doped with rare earth ions prepared in Comparative Example 3. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0035] Table 1. Raw material dosage, melting temperature, and crystallization temperature for each embodiment and comparative example.

[0036]

[0037] Example 1

[0038] The preparation method of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in this embodiment includes the following steps:

[0039] (1) Ingredient preparation and grinding: Weigh the raw materials according to Table 1 and put them into an agate mortar and grind for 30 minutes until they are evenly mixed;

[0040] (2) Melting: Pour the material after grinding in step (1) into a 200 ml alumina crucible, then place it in a lifting furnace with argon protective gas, gradually raise the temperature to 420°C and keep it at 400°C for 2 hours to form a glass melt.

[0041] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a copper mold preheated to 100°C, and then let it cool naturally until the glass melt solidifies into a glass body;

[0042] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 340°C for annealing for 10 hours.

[0043] Specifically, the heating rate during melting in step (2) is 100 degrees / hour.

[0044] Example 2

[0045] The preparation method of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in this embodiment includes the following steps:

[0046] (1) Ingredient preparation and grinding: Weigh the raw materials according to Table 1 and put them into an agate mortar and grind for 20 minutes until they are evenly mixed;

[0047] (2) Melting: Pour the material after batching and grinding in step (1) into a 200 ml alumina crucible, and then put it into a lifting furnace with argon protective gas. Gradually raise the temperature to 420°C and keep it at 420°C for 1.8 hours to form a glass melt.

[0048] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a copper mold preheated to 120°C, and then let it cool naturally until the glass melt solidifies into a glass body;

[0049] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 350°C for annealing treatment for 9 hours.

[0050] Specifically, the heating rate during melting in step (2) is 50 degrees / hour.

[0051] Example 3

[0052] The preparation method of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in this embodiment includes the following steps:

[0053] (1) Ingredient preparation and grinding: Weigh the raw materials according to Table 1 and put them into the agate mortar and grind for 25 minutes until they are evenly mixed;

[0054] (2) Melting: Pour the material after batching and grinding in step (1) into a 200 ml alumina crucible, and then put it into a lifting furnace with argon protective gas. Gradually raise the temperature to 450°C and keep it at 450°C for 1.2 hours to form a glass melt.

[0055] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a copper mold preheated to 140°C, and then let it cool naturally until the glass melt solidifies into a glass body;

[0056] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 380°C for annealing for 8.5 hours.

[0057] Specifically, the heating rate during melting in step (2) is 60 degrees / hour.

[0058] Example 4

[0059] The preparation method of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in this embodiment includes the following steps:

[0060] (1) Ingredient preparation and grinding: Weigh the raw materials according to Table 1 and put them into an agate mortar and grind for 20 minutes until they are evenly mixed;

[0061] (2) Melting: Pour the material after grinding in step (1) into a 200 ml alumina crucible, then place it in a lifting furnace with argon protective gas, gradually raise the temperature to 435℃ and keep it at 435℃ for 1 hour to form a glass melt.

[0062] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a copper mold preheated to 150°C, and then let it cool naturally until the glass melt solidifies into a glass body.

[0063] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 350°C for annealing for 8 hours.

[0064] Specifically, the heating rate during melting in step (2) is 80 degrees / hour.

[0065] Example 5

[0066] The preparation method of the bromide microcrystalline glass scintillator doped with multiple rare earth ions in this embodiment includes the following steps:

[0067] (1) Ingredient preparation and grinding: Weigh the raw materials according to Table 1 and put them into an agate mortar and grind for 20 minutes until they are evenly mixed;

[0068] (2) Melting: Pour the material after grinding in step (1) into a 200 ml alumina crucible, then place it in a lifting furnace with argon protective gas, gradually raise the temperature to 455℃ and keep it at 455℃ for 1 hour to form a glass melt.

[0069] (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a copper mold preheated to 150°C, and then let it cool naturally until the glass melt solidifies into a glass body.

[0070] (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 355°C for annealing for 8 hours.

[0071] Specifically, the heating rate during melting in step (2) is 80 degrees / hour.

[0072] Comparative Example 1

[0073] Comparative Example 1 was prepared using a similar method to Example 1, except that no other rare earth bromides were added, and the resulting product did not contain Ce. 3+ Pr 3+ 、.

[0074] Comparative Example 2

[0075] The difference between Comparative Example 2 and Example 1 is that CeBr3 was not added.

[0076] Comparative Example 3

[0077] The difference between Comparative Example 3 and Example 1 is that PrBr3 was not added.

[0078] Fluorescence spectrum curves of Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 1 ( Figure 3 , 5 -7) It can be observed that the main luminescent ions are Ce and Pr. Pr ions mainly emit light around 270 nm, while Ce ions exhibit a broad emission peak around 530 nm. 3+ The transition from the lowest 5d level to the 4f level is emitted. In Example 1, Pr is doped... 3+ and Ce 3+ Compared with the emission spectrum of Comparative Example 3, a new emission peak appeared at around 610 nm. This is because energy transfer occurred between ions within the material, Pr 3+ The 610nm red light emission peak is due to Pr 3+ The ions absorbed Ce 3+The energy transferred to it by the ion excites it to emit, indicating that Ce... 3+ -Pr 3+ Energy transfer occurs between them, which helps to increase fluorescence intensity.

[0079] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A multi-rare earth ion doped bromide microcrystalline glass scintillator, characterized in that: It is prepared from the following raw materials in the following molar percentages: 30~50 mol% ZnBr2, 20~30 mol% ABr, 10~25 mol% PbBr2, 10~20 mol% LaBr3 and 0.5~2 mol% other rare earth bromides; The other rare earth bromides mentioned are prepared by mixing CeBr3 and PrBr3 in any proportion; The ABr is one or a mixture of two or more of NaBr, KBr, and CsBr in any proportion.

2. The method for preparing a bromide microcrystalline glass scintillator doped with multiple rare earth ions according to claim 1, characterized in that: Includes the following steps: (1) Ingredient grinding: Grind the weighed ZnBr2, ABr, PbBr2, LaBr3 and other rare earth bromides together for 20-30 minutes until they are evenly mixed; (2) Melting: Pour the material after batching and grinding in step (1) into a crucible, and then put it into a lifting furnace with argon protective gas. Gradually raise the temperature to 400-500°C and keep it at 400-500°C for 1-2 hours to form glass melt; (3) Molding heat treatment: Pour the glass melt obtained in step (2) into a mold preheated to 100℃-150℃, and then let it cool naturally until the glass melt solidifies into a glass body; (4) Annealing: The glass body obtained in step (3) is quickly transferred to a muffle furnace at a temperature of 300-380℃ for annealing for 8-10 hours to obtain the bromide microcrystalline glass scintillator doped with rare earth ions.

3. The method for preparing a bromide microcrystalline glass scintillator doped with multiple rare earth ions according to claim 2, characterized in that: Step (3) Use a copper mold for forming heat treatment mold.

4. The method for preparing a bromide microcrystalline glass scintillator doped with multiple rare earth ions according to claim 2, characterized in that: The heating rate during melting in step (2) is 50-100℃ / hour.

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