阅读说明：本技术 一种铈掺杂钽铌酸镧闪烁晶体材料及其制备方法 (Cerium-doped lanthanum tantalate niobate scintillation crystal material and preparation method thereof ) 是由 丁守军 黄仙山 唐绪兵 陆羽 毛清华 于 2019-10-23 设计创作，主要内容包括：本发明提供一种铈掺杂钽铌酸镧闪烁晶体材料及其制备方法,涉及闪烁晶体技术领域,该晶体的化学式为Ce<Sub>x</Sub>La<Sub>1-x</Sub>Ta<Sub>y</Sub>Nb<Sub>1-y</Sub>O<Sub>4</Sub>,0.0001≤x≤0.1,0≤y≤1。该晶体为单斜结构,空间群为P21/c,熔点在1800℃以上,呈黄色,晶胞参数、密度、硬度随着y的取值不同而不同,该类晶体材料稳定性高,在空气中不潮解,并且具有良好的机械性能。该晶体生长原料价格较便宜、晶体物化性能稳定,可以采用熔体法晶体生长方法生长优质单晶,本发明的铈掺杂钽铌酸镧闪烁晶体作为闪烁探测器的元部件,可用于高能物理与核物理、超快脉冲辐射探测、核医学成像、太空高能射线探测及安全稽查等领域。(The invention provides a cerium-doped lanthanum tantalate niobate scintillation crystal material and a preparation method thereof, relating to the technical field of scintillation crystals x La 1‑x Ta y Nb 1‑y O 4 X is more than or equal to 0.0001 and less than or equal to 0.1, and y is more than or equal to 0 and less than or equal to 1. The crystal is of a monoclinic structure, the space group is P21/c, the melting point is above 1800 ℃, the crystal is yellow, the unit cell parameters, the density and the hardness are different along with the different values of y, and the crystal material has high stability, is not deliquescent in air and has good mechanical properties. The crystal growth raw material has low price and stable physical and chemical properties, and a melt method crystal growth method can be adopted to grow high-quality single crystalsThe lanthanum niobate scintillation crystal is used as an element component of a scintillation detector, and can be used in the fields of high-energy physics and nuclear physics, ultrafast pulse radiation detection, nuclear medicine imaging, space high-energy ray detection, safety inspection and the like.)

1. A cerium-doped lanthanum tantalate niobate scintillation crystal material is characterized in that the chemical formula of the crystal is Ce_xLa_{1- x}Ta_yNb_1-yO₄，0.0001≤x≤0.1，0≤y≤1。

2. The cerium-doped lanthanum tantalate niobate scintillation crystal material of claim 1, wherein the crystal is monoclinic structure, space group is P21/c, melting point is above 1800 ℃, and unit cell parameters, density, and hardness are different with different values of y.

3. The method for preparing a cerium-doped lanthanum tantalate niobate scintillation crystal material of claim 1 or 2, comprising the steps of:

1) by using Ce₂O₃,La₂O₃,Ta₂O₅,Nb₂O₅The raw materials are mixed according to a molar ratio of x (1-x) to y (1-y), wherein the value ranges of x and y are 0.0001-0.1 and 0-1 respectively;

2) fully mixing the raw materials prepared in the step 1), pressing the mixture into blocks by using a cold isostatic press, putting the blocks into an alumina crucible, and putting the alumina crucible into a muffle furnace to sinter the blocks into Ce_xLa_1-xTa_yNb_1-yO₄Polycrystalline raw material blocks are sintered at the temperature of 1200-1500 ℃ for 24-72 h, and the sintering gas atmosphere is air atmosphere;

3) the Ce prepared in the step 2) is_xLa_1-xTa_yNb_1-yO₄Putting the polycrystalline raw material block into an iraurita crucible for crystal growth, then putting the iraurita crucible into a pulling furnace, heating to melt, keeping the temperature for 2 hours to fully mix the melt raw materials to obtain an initial melt for crystal growth;

4) growing single crystal from the initial melt of crystal growth prepared in step 3) by melt method crystal growth process, and adopting LaTaO₄Or LanbO₄The single crystal is used as a seed crystal, and the cerium-doped lanthanum tantalate niobate scintillation crystal material is obtained through four crystal growth processes of seeding, shouldering, isometric and ending in sequence.

4. The method of preparing a cerium-doped lanthanum tantalate niobate scintillation crystal material of claim 3, wherein the purity of the initial raw materials used is: ce₂O₃:≥99.99％,La₂O₃:≥99.99％,Ta₂O₅:≥99.99％,Nb₂O₅:≥99.99％。

5. The method for preparing a cerium-doped lanthanum tantalate niobate scintillation crystal material of claim 3, wherein the melting temperature in step 3) is 1800 ℃ to 2000 ℃.

6. The method for preparing a cerium-doped lanthanum tantalate niobate scintillation crystal material of claim 3, wherein in step 4), the seed crystal pulling speed is 0.3-1mm/h, and the rotation speed is 2-10 rpm.

7. The method for preparing a cerium-doped lanthanum tantalate niobate scintillator crystal material as in claim 3, wherein the direction of the seed used in step 4) is preferably the [100], [010], [001] direction.

8. Use of the cerium-doped lanthanum tantalate niobate scintillation crystal material according to claim 1 or 2, characterized in that said scintillation crystal is used as a component of scintillation detectors in the fields of high-energy physics and nuclear physics, ultrafast pulsed radiation detection, nuclear medicine imaging, space high-energy ray detection and security inspection.

Technical Field

The invention relates to the technical field of scintillation crystals, in particular to a cerium-doped lanthanum tantalate niobate scintillation crystal material and a preparation method thereof.

Background

The inorganic scintillation crystal is a luminescent material which can emit scintillation pulse light under the action of high-energy particles (protons, neutrons) or rays (X-rays, gamma rays and the like), i.e. the inorganic scintillation crystal can be used for detecting the high-energy particles and the rays. Scintillation detection devices based on inorganic scintillation crystals have been widely used in the fields of high-energy physics and nuclear physics, ultrafast pulsed radiation detection, nuclear medicine imaging, space high-energy ray detection, security inspection and the like. For example, Bismuth Germanate (BGO), an inorganic scintillation crystal, was used extensively in the dark particle detection satellite "wushu" developed and successfully emitted by the academy of science of china in 2015 to detect high-energy cosmic rays in the universe.

In recent years, with the rapid development of related technologies such as space exploration and nuclear energy safety application, the application field of inorganic scintillation crystals is continuously widened, the application requirements are continuously increased, the application requirements are continuously improved, although the traditional scintillation crystals such as NaI, PWO and BGO have certain advantages in many aspects, certain performances are still insufficient, and the special requirements of some new application fields are difficult to meet, so that the exploration of people on novel excellent inorganic scintillation crystals is promoted. High density, fast attenuation, stable physicochemical properties and low cost are common basic requirements of excellent inorganic scintillation crystals. The high-density crystal can more effectively prevent high-energy rays or particles, so that the using amount of a scintillator is reduced, and the miniaturization of a scintillation detection device is realized; the fast attenuation is beneficial to shortening the detection time and improving the time resolution; the stable physical and chemical properties and low cost are the key points for wide popularization and application of the scintillation crystal.

Lanthanum tantalate niobate material (LaTa)_mNb_1-mO₄M is more than or equal to 0 and less than or equal to 1), has a monoclinic structure, is a self-activated luminescent material, has stable physical and chemical properties and high density (the density is 5.89g/cm along with the difference of m)³～7.79g/cm³BetweenAnd the crystal can be prepared by a pulling method, so that the crystal is a potential excellent inorganic scintillation matrix material. Ce³⁺The allowed transition of the 5d → 4f level of the ion can produce fast decaying fluorescence of tens of nanoseconds, hence by incorporating Ce in the inorganic crystalline material³⁺Ion-enabled scintillation performance is an important direction of exploration for new scintillation crystals. At present, by incorporating Ce into garnet crystals, silicate crystals, phosphate crystals and the like³⁺Ion, develops various novel scintillation crystal materials, such as Ce: YAG, Ce: LSO, Ce: LuAP and the like, which have the characteristics of high light yield, fast attenuation and the like and play an important role in promoting the miniaturization and the multifunctionality of a scintillation detection device. Although the research on the Ce3+ ion-doped inorganic scintillation crystal materials has been successful at present, the research has some problems, such as expensive crystal growth raw materials, higher melting point, difficult preparation of high-quality single crystals, self-absorption phenomenon and the like, and the application of the materials is greatly limited.

To date, there is no Ce at home and abroad³⁺The related report of ion-doped lanthanum orthotantalate niobate crystal material. La in lanthanum orthotantalate niobate crystal³⁺Lattice site symmetry of the ion is C₂，Ce³⁺The ions doped into the lanthanum orthotantalate niobate crystal can replace La³⁺Occupation of ions by C₂The symmetric lattice position is beneficial to widening the splitting of the crystal field energy level and relieving the space forbidden ring of the luminescence transition, and improves the luminous efficiency, so the crystal is expected to become a high-performance inorganic scintillation crystal material and plays a role in the fields of high-energy physics and nuclear physics, ultrafast pulse radiation detection, nuclear medicine imaging, space high-energy ray detection, safety inspection and the like.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a cerium-doped lanthanum tantalate niobate scintillation crystal material and a preparation method thereof, wherein the crystal can play a role in the fields of high-energy physics and nuclear physics, ultrafast pulse radiation detection, nuclear medicine imaging, space high-energy ray detection, safety inspection and the like.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

a cerium-doped lanthanum tantalate niobate scintillation crystal material has a chemical formula of Ce_xLa_1-xTa_yNb_1-yO₄，0.0001≤x≤0.1，0≤y≤1。

Furthermore, the crystal is of a monoclinic structure, the space group is P21/c, the melting point is above 1800 ℃, the crystal is yellow in appearance, the unit cell parameters, the density and the hardness are different along with the different values of y, and the crystal material is high in stability, free of deliquescence in air and good in mechanical property.

The preparation method of the cerium-doped lanthanum tantalate niobate scintillation crystal material comprises the following steps:

1) by using Ce₂O₃,La₂O₃,Ta₂O₅,Nb₂O₅The raw materials are mixed according to a molar ratio of x (1-x) to y (1-y), wherein the value ranges of x and y are 0.0001-0.1 and 0-1 respectively;

2) fully mixing the raw materials prepared in the step 1), pressing the mixture into blocks by using a cold isostatic press, putting the blocks into an alumina crucible, and putting the alumina crucible into a muffle furnace to sinter the blocks into Ce_xLa_1-xTa_yNb_1-yO₄Polycrystalline raw material blocks are sintered at the temperature of 1200-1500 ℃ for 24-72 h, and the sintering gas atmosphere is air atmosphere;

3) the Ce prepared in the step 2) is_xLa_1-xTa_yNb_1-yO₄Putting the polycrystalline raw material block into an iraurita crucible for crystal growth, then putting the iraurita crucible into a pulling furnace, heating to melt, keeping the temperature for 2 hours to fully mix the melt raw materials to obtain an initial melt for crystal growth;

4) growing single crystal from the initial melt of crystal growth prepared in step 3) by melt method crystal growth process, and adopting LaTaO₄Or LanbO₄The single crystal is used as a seed crystal, and the cerium-doped lanthanum tantalate niobate scintillation crystal material is obtained through four crystal growth processes of seeding, shouldering, isometric and ending in sequence.

Further, in the above-mentioned case,the purity of the starting materials used was: ce₂O₃:≥99.99％,La₂O₃:≥99.99％,Ta₂O₅:≥99.99％,Nb₂O₅:≥99.99％。

Further, the melting temperature in the step 3) is 1800-2000 ℃.

Further, the seed crystal pulling speed in the step 4) is 0.3-1mm/h, and the rotating speed is 2-10 rpm.

Further, the direction of the seed crystal used in the step 4) may be a [100], [010], or [001] direction.

The application of the cerium-doped lanthanum tantalate niobate scintillation crystal material is as follows: the scintillation crystal is used as an element component of a scintillation detector, and is used in the fields of high-energy physics and nuclear physics, ultrafast pulse radiation detection, nuclear medicine imaging, space high-energy ray detection, safety inspection and the like.

(III) advantageous effects

The invention provides a cerium-doped lanthanum tantalate niobate scintillation crystal material and a preparation method thereof, and the cerium-doped lanthanum tantalate niobate scintillation crystal material has the following beneficial effects:

1. the cerium-doped lanthanum tantalate niobate scintillation crystal of the invention is prepared by introducing Ce into a lanthanum tantalate niobate substrate with higher density³⁺Ion and control of Ce_xLa_1-xTa_yNb_1-yCe in O4³⁺Ions and Ta⁵⁺The content of ions not only can generate scintillation light and adjust the density of matrix crystals, but also Ce³⁺The crystal field effect of the ion substrate tantalum niobate is strong, Ce³⁺The scintillation luminescence decay time of the ion-doped lanthanum tantalate-niobate scintillation crystal is greatly shortened.

2. The cerium-doped lanthanum tantalate niobate scintillation crystal can adjust the density of the crystal and increase the disorder of the crystal structure by changing the proportion of Ta element and Nb element in the crystal components, and can reduce the doped Ce³⁺The lattice site symmetry of the ions improves the luminous efficiency.

3. The cerium-doped lanthanum tantalate niobate scintillation crystal has the advantages of low price of raw materials and stable physical and chemical properties of the crystal, and can grow high-quality single crystals by adopting a melt method crystal growth method.

4. The cerium-doped lanthanum tantalate niobate scintillation crystal provided by the invention is used as an element component of a scintillation detector, and can be used in the fields of high-energy physics and nuclear physics, ultrafast pulse radiation detection, nuclear medicine imaging, space high-energy ray detection, safety inspection and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Pure LanbO of FIG. 1₄A crystal;

FIG. 2Ce of example 1_0.02La_0.98NbO₄A crystal;

FIG. 3 Ce of example 1_0.02La_0.98NbO₄Powder XRD pattern of the crystals.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.