Rare earth borate scintillator and preparation method thereof

Abstract

The invention discloses a rare earth borate scintillator and a preparation method thereof, and belongs to the technical field of inorganic luminescent materials. A solid-phase sintering method is adopted, high-purity rare earth oxide and boric acid are used as raw materials, and a series of scintillator materials with the chemical general formula of A1-xMxBO3 are prepared by accurately controlling the stoichiometric ratio. The series of materials have excellent photoluminescence and radiation luminescence properties, the fluorescence quantum yield can reach 90% at most, the light yield can reach 35,000 photons / MeV at most, and compared with a traditional scintillator, the fluorescence quantum yield and the light yield are remarkably improved. By optimizing the sintering temperature and time, uniform distribution of rare earth ions and effective inhibition of lattice defects are achieved, the method is remarkably superior to the prior art in the aspects of light yield, anti-radiation stability and the like, complex post-treatment is not needed in the preparation process, and the method has industrial application prospects in the fields of medical imaging, radiation detection and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic luminescent materials, and relates to a rare earth borate scintillator and a preparation method thereof. Background Art

[0002] With the rapid development of fields such as nuclear medicine imaging, high-energy physics detection, and radiation monitoring, as the core component for energy conversion, the performance of scintillator materials directly affects the sensitivity, resolution, and response speed of detection systems. Traditional commercial scintillators (such as NaI:Tl, CsI:Tl, Bi 4 Ge 3 O 12 etc.) have been widely used, but they have significant defects, resulting in high manufacturing costs and poor environmental adaptability. For example, NaI:Tl and CsI:Tl are prone to deliquescence and require complex encapsulation processes; Bi 4 Ge 3 O 12 has a light yield (about 8,000 photons / MeV), which limits the weak signal detection ability.

[0003] Rare earth oxyacid salts such as LuAG:Ce, LYSO:Ce, etc. have become research hotspots for new scintillators due to their high density, high radiation hardness, and efficient luminescence characteristics of rare earth ions. Rare earth ions (such as Ce3+, Eu2+, Tb 3 +) can form efficient luminescence centers in the matrix. However, the preparation of such materials usually requires extremely high synthesis temperatures (>1500°C), and has strict requirements for equipment and synthesis conditions. Based on the above technical status and environmental considerations, the development of new scintillator materials with cost-effectiveness and environmental friendliness will open up new research hotspots for the radiation detection field, not only meeting the concept of sustainable development, but also meeting the growing demand for high-performance radiation detection. Summary of the Invention

[0004] The purpose of the present invention is to meet the low-cost and easy-preparation requirements for the preparation of inorganic rare earth scintillators, and to provide a rare earth borate scintillator and a preparation method thereof. This scintillator material has the characteristics of high emission intensity and wide excitation range, and at the same time has the advantages of simple preparation process, high sensitivity, wide applicability, and fast response.

[0005] A rare earth borate scintillator has a chemical general formula of A 1-x M x BO 3 , 0.005 ≤ x ≤ 0.10, where A is at least one of Y, Gd, or Lu, M is at least one of Eu, Tb, Sm, or Dy, and x is the doping content.

[0006] A preparation method of a rare earth borate scintillator includes the following steps:

[0007] Step S1, weigh the rare earth oxide and boric acid according to the molar ratio and transfer them to an agate mortar.

[0008] Step S2, add a small amount of ethanol for wet grinding until the ethanol evaporates, and repeat three times to make the raw materials evenly mixed.

[0009] Step S3, transfer the well-ground sample to an alumina crucible and calcine it at 1100 °C for 4 hours.

[0010] Step S4, take out the crucible after cooling to room temperature with the furnace, pour out the product inside and grind it to obtain the rare earth borate scintillator.

[0011] The present invention proposes a novel rare earth borate scintillator and its preparation method, which realizes the uniform distribution of rare earth ions and effectively suppresses lattice defects while reducing the synthesis temperature (1100 °C). This material is significantly superior to the prior art in terms of light yield and anti-irradiation stability, and the preparation process does not require complex post-treatment, having the potential for industrial application. Brief Description of the Drawings

[0012] Figure 1 is the rare earth borate scintillator A of the present invention 1-x M x BO 3 (0.005 ≤ x ≤ 0.10) preparation flow chart.

[0013] Figure 2 is the Gd prepared in Example 1 of the present invention 0.95 Eu 0.05 BO 3 Scanning electron microscope photograph of the scintillator.

[0014] Figure 3 is the Gd prepared in Example 1 of the present invention 0.95 Eu 0.05 BO 3 Radiation luminescence spectrum of the scintillator.

[0015] Figure 4 is the Gd prepared in Example 2 of the present invention 0.95 Tb 0.05 BO 3 Radiation luminescence spectrum of the scintillator.

[0016] Figure 5 is the Gd prepared in Example 3 of the present invention 0.98 Sm 0.02 BO 3 Radiation luminescence spectrum of the scintillator.

[0017] Figure 6 is the Gd prepared in Example 4 of the present invention 0.98 Dy 0.02BO 3 Radiation emission spectrum of the scintillator.

[0018] Figure 7 is the Y prepared in Example 5 of the present invention 0.95 Eu 0.05 BO 3 Radiation emission spectrum of the scintillator.

[0019] Figure 8 is the Lu prepared in Example 6 of the present invention 0.95 Eu 0.05 BO 3 Radiation emission spectrum of the scintillator. Detailed implementation manners

[0020] The present invention will be further described below through examples.

[0021] The present invention provides a novel rare earth borate scintillator and its preparation method. By optimizing the synthesis conditions, it aims to achieve a scintillator with a simple preparation process, good luminescence performance, low production cost, and high reproducibility, meeting the requirements of modern medical imaging and industrial detection for high-performance scintillators.

[0022] The present invention uses a solid-phase sintering method, with high-purity rare earth oxides (purity ≥ 99.99%) and boric acid (H 3 BO 3 , 99.99%) as raw materials. By precisely controlling the stoichiometric ratio, a series of scintillator materials with the chemical general formula A 1-x M x BO 3 (0.005 ≤ x ≤ 0.10) are prepared, where A represents one of Y, Gd, or Lu, M represents one of Eu, Tb, Sm, or Dy, and x represents the doping content.

[0023] The preparation method of the rare earth borate scintillator of the present invention includes the following steps:

[0024] Step S1, weigh rare earth oxides and boric acid according to the molar ratio and transfer them to an agate mortar.

[0025] Step S2, add a small amount of ethanol for wet grinding until the ethanol evaporates, and repeat three times to make the raw materials evenly mixed.

[0026] Step S3, transfer the well-ground sample to an alumina crucible and calcine it at 1100 °C for 4 hours.

[0027] Step S4, take out the crucible after cooling to room temperature with the furnace, pour out the product inside and grind it to obtain the rare earth borate scintillator.

[0028] The fluorescence quantum yield of the rare earth borate scintillator of the present invention can reach up to 90%, and the light yield is increased by 60% compared with the commercial LuAG:Ce scintillator.

[0029] Example 1

[0030] This example describes the preparation method of the Gd 0.95 Eu 0.05 BO 3 scintillator, and the operation steps are Figure 1 shown as follows:

[0031] Weigh 1.7219 g (4.75 mmol) of Gd 2 O 3 , 0.088 g (0.25 mmol) of Eu 2 O 3 , 0.6183 g (10 mmol) of H 3 BO 3 , put them into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry them in an oven at 70 °C to obtain mixed powder;

[0032] Put the evenly ground powder into an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0033] Grind the cooled powder obtained in step b) for 5 min to obtain the scintillator material Gd 0.95 Eu 0.05 BO 3 .

[0034] Figure 2 shows the scanning electron microscope (SEM) photograph of the Gd 0.95 Eu 0.05 BO 3 scintillator. The prepared Gd 0.95 Eu 0.05 BO 3 sample has a uniform morphology and a smooth surface, and the average size is about 17 μm.

[0035] Figure 3 shows the radioluminescence spectrum of the Gd 0.95 Eu 0.05 BO 3 scintillator. The radioluminescence spectrum of the Gd 0.95 Eu 0.05 BO 3 sample presents a characteristic emission peak of Eu 3+ at 592 nm, and this emission peak corresponds to the 3+ of Eu 5 D0 → 7 F 1 Magnetic dipole transition, showing typical red luminescence characteristics. Using commercial LuAG:Ce scintillator as a reference (light yield of about 22,000 photons / MeV), the relative light yield of this Gd 0.95 Eu 0.05 BO 3 scintillator is about 35,000 photons / MeV.

[0036] Example 2

[0037] This example supplements Gd 0.95 Tb 0.05 BO 3 Preparation method of scintillator, the operation steps are as follows:

[0038] Weigh 1.7219 g (4.75 mmol) Gd 2 O 3 , 0.0935 g (0.25 mmol) Tb 4 O 7 , 0.6183 g (10 mmol) H 3 BO 3 , put them into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry them in an oven at 70 °C to obtain mixed powder;

[0039] Put the evenly ground powder in an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0040] Grind the cooled powder obtained in step b) for 5 min to obtain the scintillator material Gd 0.95 Tb 0.05 BO 3 .

[0041] Figure 4 Shows the radioluminescence spectrum of Gd 0.95 Tb 0.05 BO 3 scintillator. The radioluminescence spectrum of the Gd 0.95 Tb 0.05 BO 3 sample presents a Tb 3+ characteristic emission peak at 550 nm, showing typical green luminescence characteristics.

[0042] Example 3

[0043] This example supplements Gd 0.98 Sm0.02 BO 3 The preparation method of the scintillator is as follows:

[0044] Weigh 1.7763 g (4.9 mmol) of Gd 2 O 3 , 0.0349 g (0.1 mmol) of Sm 2 O 3 , 0.6183 g (10 mmol) of H 3 BO 3 , put them into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry them in an oven at 70 °C to obtain mixed powder;

[0045] Put the evenly ground powder in an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0046] Grind the cooled powder obtained in the above steps for 5 min to obtain the scintillator material Gd 0.98 Sm 0.02 BO 3 .

[0047] Figure 5 shows the radioluminescence spectrum of the Gd 0.98 Sm 0.02 BO 3 scintillator. The radioluminescence spectrum of the Gd 0.98 Sm 0.02 BO 3 sample presents a characteristic emission peak of Sm at 600 nm, showing typical orange-red luminescence characteristics. 3+ 3+

[0048] Example 4

[0049] The preparation method of the Gd 0.98 Dy 0.02 BO 3 scintillator in this example is as follows:

[0050] Weigh 1.7763 g (4.9 mmol) of Gd 2 O 3 , 0.0373 g (0.1 mmol) of Dy 2 O 3 , 0.6183 g (10 mmol) of H 3 BO 3, put it into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry it in an oven at 70 °C to obtain the mixed powder;

[0051] Put the evenly ground powder in an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0052] Grind the cooled powder obtained in step b) for 5 min to obtain the scintillator material Gd 0.98 Dy 0.02 BO 3 .

[0053] Figure 6 Shows the radioluminescence spectrum of Gd 0.98 Dy 0.02 BO 3 scintillator. The radioluminescence spectrum of Gd 0.98 Dy 0.02 BO 3 The radioluminescence spectrum of the sample shows a Dy 3+ characteristic emission peak at 575 nm, showing typical orange-yellow luminescence characteristics.

[0054] Example 5

[0055] This example supplements Y 0.95 Eu 0.05 BO 3 preparation method of the scintillator, and the operation steps are as follows:

[0056] Weigh 1.0726 g (4.75 mmol) of Y 2 O 3 , 0.088 g (0.25 mmol) of Eu 2 O 3 , 0.6183 g (10 mmol) of H 3 BO 3 , put it into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry it in an oven at 70 °C to obtain the mixed powder;

[0057] Put the evenly ground powder in an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0058] Grind the cooled powder obtained in the above step for 5 min to obtain the scintillator material Y 0.95 Eu 0.05 BO 3 .

[0059] Figure 7 shows Y 0.95 Eu 0.05 BO 3 The radioluminescence spectrum of the scintillator. Y 0.95 Eu 0.05 BO 3 The radioluminescence spectrum of the sample shows a Eu 3+ characteristic emission peak at 592 nm, showing typical red luminescence characteristics.

[0060] Example 6

[0061] This example supplements Lu 0.95 Eu 0.05 BO 3 A preparation method of the scintillator, the operation steps are as follows:

[0062] Weigh 1.8900 g (4.75 mmol) of Lu 2 O 3 , 0.088 g (0.25 mmol) of Eu 2 O 3 , 0.6183 g (10 mmol) of H 3 BO 3 , put them into an agate mortar, then add an appropriate amount of absolute ethanol to the mixed raw materials and grind until the ethanol volatilizes. After mixing evenly three times, dry them in an oven at 70 °C to obtain mixed powder;

[0063] Put the evenly ground powder in an alumina crucible, heat it to 1100 °C at a heating rate of 9 °C / min, calcine for 4 hours, and then naturally cool to room temperature;

[0064] Grind the cooled powder obtained in the above steps for 5 min to obtain the scintillator material Lu 0.95 Eu 0.05 BO 3 .

[0065] Figure 8 shows Lu 0.95 Eu 0.05 BO 3 The radioluminescence spectrum of the scintillator. Lu 0.95 Eu 0.05 BO 3 The radioluminescence spectrum of the sample shows a Eu 3+ characteristic emission peak at 592 nm, showing typical red luminescence characteristics.

[0066] The present invention discloses a rare earth borate scintillator and a preparation method thereof. The present invention adopts a solid-phase sintering method, using high-purity rare earth oxides (purity ≥ 99.99%) and boric acid (H 3 BO3 Using materials with a purity of 99.99% as raw materials, by precisely controlling the stoichiometric ratio, a series of scintillator materials with the chemical general formula A 1-x M x BO 3 (0.005 ≤ x ≤ 0.10) are prepared. Among them, A is at least one of Y, Gd, or Lu, M is at least one of Eu, Tb, Sm, or Dy, and x represents the doping content. This series of materials has excellent photoluminescence and radioluminescence properties. Its fluorescence quantum yield (PLQY) can reach up to 90%, and the light yield can reach up to 35,000 photons / MeV, which is significantly improved compared with traditional scintillators. By optimizing the sintering temperature and time, the present invention realizes the uniform distribution of rare earth ions and effectively suppresses lattice defects, is significantly superior to the prior art in terms of light yield and radiation resistance stability, and the preparation process does not require complex post-treatment, having an industrial application prospect in the fields of medical imaging and radiation detection, etc.

Claims

1. A rare earth borate scintillator, characterized in that: The chemical formula is A 1-x M x BO3, 0.005≤x≤0.10, wherein A is at least one of Y, Gd or Lu, M is at least one of Eu, Tb, Sm or Dy, and x is the doping content.

2. A method for preparing the rare earth borate scintillator according to claim 1, characterized in that: The following steps are involved: Step S1, weighing rare earth oxide and boric acid in a molar ratio and transferring them into an agate mortar; Step S2, adding a small amount of ethanol for wet grinding until the ethanol evaporates, repeating three times to make the raw materials evenly mixed; Step S3, transferring the fully ground sample into an alumina crucible and calcining it at 1100° C. for 4 hours; Step S4, after the furnace is cooled to room temperature, the crucible is taken out, the product inside is poured out and ground to obtain a rare earth borate scintillator.

Images