A scintillation crystal and its growth method and apparatus

Abstract

One embodiment of this specification provides a scintillation crystal, a growth method thereof, and a growth apparatus. The molecular formula of the scintillation crystal is as follows: where X consists of Ce, M consists of one or more of Ca, Mg, Sr, Mn, Ba, Al, Fe, Re, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, Sc, and at least one of Ca and Mg is included in M, Q consists of O, N consists of one or more of Cl, F, Br, S; and at least Cl is included in N; x = 0.0000001 - 0.06, m = 0 - 0.06, 0 ≤ z < 1, 0 < n < 10; when preparing the scintillation crystal, a first dopant and a second dopant are added, the first dopant is a compound containing the Ce, and the second dopant is a compound containing the M.

Description

Case Analysis

[0001] This case is a divisional application of Chinese patent application entitled "A scintillation crystal and its growth method and apparatus", filed on October 7, 2023, with application number "202311301252.3". Technical Field

[0002] This specification relates to the field of artificial crystal growth, and in particular to a scintillation crystal and its growth method and apparatus. Background Technology

[0003] Cerium (Ce) is used as an activator for scintillation crystals. For a long time, its tetravalent ion was considered by the academic community to have an adverse effect on scintillation crystals. For example, CN103249805B mentions that the electronic defects causing afterglow are related to the presence of oxygen vacancies in the scintillation material. Samples co-doped with calcium or magnesium contain fewer oxygen vacancies and exhibit strong absorption between 150 nm and 350 nm. This absorption band originates from tetravalent cerium ions (Ce). 4+ Because it does not shimmer and can cause materials to fade, its presence is considered detrimental to improving the afterglow of scintillation crystals.

[0004] Later, through practice, it was found that Ce 4+ This helps improve the afterglow of the scintillation crystal. Among the Ce-doped rare-earth silicate scintillation materials disclosed in the aforementioned patent document (i.e., CN103249805B), there exists a material whose absorbance at 357 nm is lower than its absorbance at 280 nm. This absorbance characteristic implies that Ce... 4+ Therefore, there exists a quantity sufficient to improve the afterglow.

[0005] By doping with divalent cations, especially Ca 2+ and Mg 2+ These methods can improve the scintillation performance of scintillation crystals to some extent. As described in the aforementioned patent document, good scintillation performance and production rate can be obtained by controlling the concentration and / or ratio of doped Group II elements. In the melt used to form the scintillation crystal, doped Ce (atomic concentration 0.11%) can act as an activator in rare earth silicates; doped Ca (atomic concentration 0.1% to 0.2%) can be used to reduce the decay time of the scintillation crystal.

[0006] However, this scintillation crystal growth is not stable. Higher Ca concentrations can lead to increased melt viscosity, decreased surface tension, and reduced heat transfer, affecting the stability of crystal growth.

[0007] Therefore, it is necessary to provide a scintillation crystal and its growth method and apparatus, so that the prepared scintillation crystal grows stably and has better scintillation performance. Summary of the Invention

[0008] One embodiment of the present specification provides a scintillation crystal, and the molecular formula of the scintillation crystal is shown as follows: , where X is composed of Ce, M is composed of one or more of Ca, Mg, Sr, Mn, Ba, Al, Fe, Re, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, Sc; Q is composed of O, and N is composed of one or more of Cl, F, Br, S; and at least Cl is included in N; x = 0.0000001 - 0.06, m = 0 - 0.06, 0 ≤ z < 1, 0 < n < 10.

[0009] One embodiment of the present specification provides a method for growing a scintillation crystal, which is used to grow the scintillation crystal described in any technical solution of the present specification; the reaction equation for generating the scintillation crystal is: , where x = 0.0000001 - 0.06, 0 < s < 0.05, 0 ≤ y < 1, 0 ≤ z < 1, 0 < n < 10; the method includes: weighing each reaction material according to the molar ratio based on the reaction equation; growing the scintillation crystal by the upward pulling method.

[0010] One embodiment of the present specification provides a scintillation crystal growth device, which includes a furnace chamber, a temperature field device, a lifting rod, a heating device, and a first driving device; the temperature field device and the heating device are arranged in the furnace chamber; at least a part of the lifting rod is located in the furnace chamber; the first driving device is connected to the lifting rod to drive the lifting rod to move along the axial direction of the lifting rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present specification will be further described in the form of exemplary embodiments, and these exemplary embodiments will be described in detail through the drawings. These embodiments are not restrictive. In these embodiments, the same numbers represent the same structures, where: Figure 1 is a schematic diagram of a scintillation crystal shown in some embodiments of the present specification; Figure 2A is an exemplary schematic diagram of a scintillation crystal growth device shown in some embodiments of the present specification; Figure 2B is a schematic diagram of the structure of a vacuum furnace shown in some embodiments of the present specification; Figure 2C is a schematic diagram of the structure of an open furnace shown in some embodiments of the present specification; Figure 2D is a schematic diagram of the temperature field device of an open furnace shown in some embodiments of the present specification; Figure 3 This is an exemplary flowchart of a scintillation crystal growth method according to some embodiments of this specification; Figure 4 This is a schematic diagram of a fully oxidized scintillation crystal according to some embodiments of this specification; Figure 5 This is a schematic diagram of a scintillation crystal according to other embodiments of this specification; Figure 6 This is a schematic diagram of a scintillation crystal according to some embodiments of this specification; Figure 7 This is a schematic diagram of a scintillation crystal according to some embodiments of this specification; Figure 8 This is a schematic diagram of a scintillation crystal according to some embodiments of this specification.

[0012] Explanation of reference numerals in the attached drawings: 200, scintillation crystal growth apparatus; 201, vacuum furnace; 202, open furnace; 210, furnace chamber; 220, temperature field device; 221, crucible; 230, lifting rod; 240, heating device; 250, first driving device; 260, second driving device; 251, lifting assembly; 252, rotating assembly; 253, weighing device; 226, first base plate; 229, furnace frame; 2210, motion device; 222, base plate; 223, first cylinder; 224, second cylinder; 225, filler; 227, second cover plate; 228, heating element; 2213, induction coil. Detailed Implementation

[0013] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0014] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0015] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0016] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0017] Scintillation crystals are widely used in nuclear medicine, such as X-ray computed tomography (XCT) and positron emission tomography (PET), nuclear detection technologies such as industrial computed tomography (industrial CT), oil well exploration, nuclear physics, high-energy physics, environmental monitoring, safety monitoring, weapon fire control, and guidance. Especially in high-energy physics and nuclear medicine imaging, scintillation crystals are required to have high light yield, strong gamma-ray absorption capacity, short emission decay time, and high irradiation hardness, density, and atomic number.

[0018] Cerium-doped lutetium silicate (LSO) is a high-density, high-atomic-order scintillation crystal with unique advantages such as fast response time to gamma rays, high light yield, certain energy resolution, non-hygroscopicity, and low sensitivity to neutrons. It is one of the best-performing scintillation crystals currently available.

[0019] By doping with divalent cations, especially Ca 2+ and Mg 2+ Certain additives can improve the scintillation properties of cerium-doped scintillation crystals to some extent. However, their growth is not stable. Higher Ca concentrations may lead to increased melt viscosity, decreased surface tension, and reduced heat transfer, affecting the stability of crystal growth.

[0020] But how to control the second dopant in the scintillation crystal (e.g., containing divalent cations Ca)? 2+ Mg 2+ The total content of compounds (such as Ce) in scintillation crystals, and how to adjust Ce 4+ and / or Ce 3+ The content of scintillation crystals in crystals has become an urgent problem to be solved in order to improve the performance of scintillation crystals.

[0021] In production practice, it has been found that even if the purity of raw materials meets the standard requirements, the content of various impurity elements (such as Cl, Ca, etc.) will vary from batch to batch, which will have an adverse impact on production.

[0022] Some existing technologies avoid this effect by limiting the content of certain impurity elements in the raw materials, which affects Ce in scintillation crystals. 4+ and / or Ce 3+ The content is adjusted by reheating the crystal to a certain temperature after crystal growth and then allowing oxygen diffusion and adding divalent cations. These methods significantly increase production costs.

[0023] However, this application introduces Cl - Anions are used to reduce the total content of Group II elements such as Ca and Mg, thereby achieving the control of Ce in L(Y)SO crystals. 4+ and / or Ce 3+ The content of [unspecified element] is controlled to avoid the impact of fluctuations in the content of different impurity elements in different batches on crystal growth and crystal properties, without significantly increasing production costs. The introduced Cl [unspecified element] - It can replenish some oxygen vacancies in the scintillation crystal and regulate Ce in the scintillation crystal. 4+ and / or Ce 3+ The content of [unspecified substance], together with divalent cations such as Ca and Mg, can reduce afterglow and effectively improve the scintillation performance of scintillation crystals. - It can be obtained through CeCl3 or CeCl4 containing Cl. - The compound was introduced.

[0024] Figure 1 This is an exemplary schematic diagram of a scintillation crystal according to some embodiments of this specification.

[0025] This specification provides an embodiment of a scintillation crystal, the molecular formula of which may be as follows: Wherein, X is composed of Ce, M is composed of one or more of Ca, Mg, Sr, Mn, Ba, Al, Fe, Re, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, and Sc, Q is composed of O, and N is composed of one or more of Cl, F, Br, and S; and N includes at least Cl.

[0026] Scintillation crystals are crystals that can convert the kinetic energy of high-energy particles, such as X-rays, into light energy and emit a flash when struck.

[0027] 2x represents the doping concentration of element X, 2m represents the doping concentration of element M, and 2z represents the doping concentration of trivalent yttrium ions (Y). 3+ The doping concentration of N is denoted by n, where n represents the atomic concentration of N element.

[0028] In some embodiments, the value of x can be 0.0000001 - 0.06 (this representation includes the boundary values 0.0000001 and 0.06). The value of x can also be 0.00001 - 0.06. The value of x can also be 0.0001 - 0.06. The value of x can also be 0.001 - 0.06. The value of x can also be 0.01 - 0.06. The value of x can also be 0.02 - 0.05. The value of x can also be 0.03 - 0.04. The value of x can also be 0.031 - 0.039. The value of x can also be 0.032 - 0.038. The value of x can also be 0.033 - 0.037. The value of x can also be 0.034 - 0.036. In some embodiments, the value of m can be 0 - 0.06. The value of m can also be 0.001 - 0.06. The value of m can also be 0.002 - 0.05. The value of m can also be 0.003 - 0.04. The value of m can also be 0.0031 - 0.0039. The value of m can also be 0.0032 - 0.0038. The value of m can also be 0.0033 - 0.0037. The value of m can also be 0.0034 - 0.0036. In some embodiments, the value of z can be 0 ≤ z < 1. The value of z can also be 0.1 - 0.9. The value of z can also be 0.2 - 0.8. The value of z can also be 0.3 - 0.7. The value of z can also be 0.4 - 0.6. The value of z can also be 0.42 - 0.58. The value of z can also be 0.44 - 0.56. The value of z can also be 0.46 - 0.54. The value of z can also be 0.48 - 0.52. The value of z can also be 0.49 - 0.51. In some embodiments, the value of n can be 0 < n < 10. The value of n can also be 0.5 - 4.5. The value of n can also be 1 - 4. The value of n can also be 1.5 - 3.5. The value of n can also be 2 - 3. The value of n can also be 2.2 - 2.8. The value of n can also be 2.4 - 2.6.

[0029] In some embodiments, X can be composed of Ce, M can be composed of Ca or M can be composed of Ca and Sc, Q can be composed of O, N can be composed of Cl, and the scintillation crystal can have the following molecular formula: . In this specification, the scintillation crystal of the above molecular formula can be abbreviated as Ce:Ca:LYSSOC.

[0030] It can be understood that the corresponding 2x represents the doping concentration of trivalent cerium ions (Ce 3+ ) and tetravalent cerium ions (Ce 4+ ), that is, the proportion of Ce 3+ occupying the lattice sites of lutetium (Lu) atoms, and 2s represents divalent calcium ions (Ca 2+). The proportion occupied in the scintillation crystal lattice, 2y represents the doping concentration of trivalent scandium ions (Sc 3+ ), 2z represents the atomic concentration of trivalent yttrium ions (Y 3+ ), n represents the atomic concentration of chlorine ions (Cl - ).

[0031] For the values of x, z, and n, reference can be made to the aforementioned relevant descriptions and will not be elaborated here. In some embodiments, the value of s can be 0 < s < 0.05, the value of s can also be 0.01 - 0.04, the value of s can also be 0.02 - 0.03, the value of s can also be 0.021 - 0.029, the value of s can also be 0.022 - 0.028, the value of s can also be 0.001, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, etc. The value of y can be 0 ≤ y < 1, the value of y can also be 0.1 - 0.9, the value of y can also be 0.3 - 0.7, the value of y can also be 0.4 - 0.6, the value of y can also be 0.51 - 0.59, the value of y can also be 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, 0.005, 0.001, etc. In some embodiments, the sum of the value of s and the value of y can be equal to the value of m.

[0032] By further limiting y and s within this range, the scintillation performance of the scintillation crystal can be improved (such as reducing the afterglow of the scintillation crystal, increasing the light output, etc.), and together with Cl - to achieve the regulation of the content of Ce 4+ and / or Ce 3+ in the scintillation crystal.

[0033] In some embodiments, the mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can be 0.01 ppm to 1000 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 0.1 ppm to 900 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 0.1 ppm to 800 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 0.1 ppm to 700 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 0.1 ppm to 500 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 0.1 ppm to 200 ppm. The mass ratio of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the scintillation crystal can also be 100 ppm to 150 ppm.

[0034] By including Cl in the scintillation crystal, some oxygen vacancies can be filled. The concentration of Ce in the scintillation crystal can be adjusted by setting the ratio of the mass of Cl to the sum of the masses of Lu, Ce, Sc, and Y in the crystal to 0.01 ppm–1000 ppm. 4+ and / or Ce 3+ The content of [something] is used to reduce afterglow and increase light yield in scintillation crystals.

[0035] Scintillation crystals are produced by doping with Ce, Y, and Sc (scandium, Sc). +3 By using a radius of 0.0745 nm and Ca (calcium), the resulting scintillation crystal can be larger. In some embodiments, the crystal diameter can reach 70 mm-115 mm, and the crystal weight is 6500 g-13000 g. Furthermore, the crystal growth exhibits good repeatability and performance consistency, and tests show few macroscopic defects.

[0036] By specifying the molecular formula and elemental concentration ratios of the scintillation crystal, compositional deviations can be avoided, ensuring consistent Ce doping concentration under different process conditions. This results in excellent crystal growth repeatability and superior overall performance, making it a promising candidate for applications in nuclear medicine, industrial CT, security inspection, and environmental monitoring. Testing shows that the scintillation crystals provided in this specification can achieve diameters of 70mm-115mm and constant diameter lengths of 130mm-200mm. The constant diameter length refers to the diameter achieved during the constant diameter process in the upward pulling method. The crystal density can reach 7-7.4g / cm³; the emission center wavelength can reach 350-450nm; the light output can reach 23000ph / MeV and above; the energy resolution can reach ≤9%; and the decay time can be as low as 35ns or less, demonstrating excellent overall performance.

[0037] In some embodiments, the elements in the scintillation crystal have different mass ratios.

[0038] In some embodiments, the mass ratio of Ca to Ce in the scintillation crystal may not exceed 300. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-250. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-200. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-150. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-100. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-50. The mass ratio of Ca to Ce in the scintillation crystal may also be 0.001-20.

[0039] By limiting the mass ratio of Ca to Ce in the scintillation crystal, it is possible to improve the crystal decay time and increase the light yield (greater than 28000ph / MeV).

[0040] In some embodiments, the scintillation crystal contains at least 1 ppm Ce. 3+ and / or Ce 4+ .

[0041] By limiting Ce in the scintillation crystal 3+ and / or Ce 4+ The content of [specific element] can achieve the effect of improving afterglow and reducing the decay time of scintillation crystals.

[0042] In some embodiments, a first dopant and a second dopant may be added during the fabrication of the scintillation crystal.

[0043] The first dopant is a Ce-containing compound. Examples include CeO2, Ce2O3, CeCl3, and CeCl4. In some embodiments, the mass ratio of Ce to rare earth elements in the first dopant can be at least 10 ppm. The mass ratio of Ce to rare earth elements in the first dopant can also be 10-500 ppm. The mass ratio of Ce to rare earth elements in the first dopant can also be 100-400 ppm. The mass ratio of Ce to rare earth elements in the first dopant can also be 200-300 ppm.

[0044] In some embodiments, the second dopant may include element M. Further details regarding element M can be found in the foregoing description. In some embodiments, the second dopant may include elements Ca and Sc. For example, the second dopant may be Sc₂O₃, CaO, etc. In some embodiments, the mass ratio of M to rare earth elements in the second dopant may be 0.1 ppm to 500 ppm. The mass ratio of M to rare earth elements in the second dopant may also be 1 ppm to 499 ppm. The mass ratio of M to rare earth elements in the second dopant may also be 100 ppm to 400 ppm. The mass ratio of M to rare earth elements in the second dopant may also be 250 ppm to 350 ppm. The mass ratio of M to rare earth elements in the second dopant may also be 301 ppm to 309 ppm.

[0045] As is understandable, rare earth elements refer to Y, Sc, and the lanthanides (La to Lu) in the periodic table. As an example only, if the molecular formula of a scintillation crystal is... Then, the mass ratio of Ce in the first dopant to all rare earth elements (Lu, Y, Sc, Ce) in the scintillation crystal can be at least 10 ppm; if the molecular formula of the scintillation crystal is Then, the mass ratio of Ce in the first dopant to all rare earth elements (Lu, Y, Ce) in the scintillation crystal can be at least 10 ppm; if the molecular formula of the scintillation crystal is Then the mass ratio of Ce in the first dopant to all rare earth elements (Lu, Ce) in the scintillation crystal can be at least 10 ppm.

[0046] In some embodiments, the mass ratio of M in the second dopant to Ce in the first dopant is 0.01-50. The mass ratio of M in the second dopant to Ce in the first dopant can also be 0.1-40. The mass ratio of M in the second dopant to Ce in the first dopant can also be 1-30. The mass ratio of M in the second dopant to Ce in the first dopant can also be 15-20.

[0047] By limiting the type of the first dopant and the mass ratio of Ce to rare earth elements in the first dopant, the light yield of the crystal can be improved. By limiting the type of the second dopant and the mass ratio of M to rare earth elements in the second dopant, as well as the mass ratio of M in the second dopant to Ce in the first dopant, crystal embryos without helices or with very low helices can be grown, achieving good (short) decay time and scintillation performance.

[0048] In some embodiments, the reaction equation for generating the scintillation crystal is: , where \(x = 0.0000001 - 0.06\), \(0 < s < 0.05\), \(0\leq y < 1\), \(0\leq z < 1\), \(0 < n < 10\); the method for growing the scintillation crystal includes: based on the reaction equation, growing the scintillation crystal using the upward pulling method. For more content about the method for growing the scintillation crystal, reference can be made to Figure 3 and its related descriptions.

[0049] Figure 2A is an exemplary schematic diagram of a scintillation crystal growth device according to some embodiments of the present specification. <*

[0050] In some embodiments, as Figure 2A shown, the scintillation crystal growth device 200 may be a single crystal growth furnace (such as a vacuum furnace, an open furnace, etc.). This scintillation crystal growth device can be used to grow the scintillation crystal described in any of the above technical solutions. The scintillation crystal growth device 200 may include a furnace chamber 210, a temperature field device 220, a pulling rod 230, a heating device 240, and a first driving device 250. A temperature field device 220 and a heating device 240 are provided in the furnace chamber 210. At least a part of the pulling rod 230 is located in the furnace chamber 210. The first driving device 250 is connected to the pulling rod 230 to drive the pulling rod 230 to move along the axial direction of the pulling rod.

[0051] In some embodiments, the furnace chamber 210 refers to a place for accommodating multiple components required for crystal growth and providing a place for crystal growth. The furnace chamber 210 may be in the shape of a cylinder, a cube, a cuboid, etc. The temperature field device 220 can provide a place and a temperature gradient required for crystal growth to ensure the stability of the crystal crystallization process. The heating device 240 can provide the temperature required for crystal growth. In some embodiments, the heating device 240 may be a heating coil. In some embodiments, the heating coil may have an inner diameter of (250 mm - 330 mm) × height (155 mm - 270 mm) × (7 - 9 turns). The bottom of the pulling rod 230 may be connected to a seed crystal to serve as a crystal growth seed. The first driving device 250 is used to drive the pulling rod to move, so as to realize the rising or falling of the pulling rod 230, thereby realizing the growth of the scintillation crystal by the upward pulling method. The first driving device 250 may include a motor, a hydraulic cylinder, a pneumatic motor, etc. In some embodiments, the first driving device 250 may drive the pulling rod 230 to rotate around the axis of the pulling rod. The first driving device 250 and the pulling rod 230 may be传动连接 (such as bolt connection, welding, hinged connection, clamping connection, etc.) to drive the pulling rod 230 to move.

[0052] In some embodiments, the temperature field device 220 further includes a crucible 221. The crucible 221 is used to place the raw materials for crystal growth. In other parts of this specification, the melt is the raw material for crystal growth. In some embodiments, the crucible 221 may be made of various materials, for example, an iridium crucible, a molybdenum crucible, etc. It should be noted that there may be an error in the Chinese character "传动连接" in the original text. I have translated it as "传动连接" as it is, but it might be more accurately expressed as "transmission connection" or other appropriate terms in a more standard English context. You can adjust it according to the actual situation.

[0053] In some embodiments, the scintillation crystal growth apparatus 200 further includes a second driving device 260. The second driving device 260 can drive the crucible 221 to rotate about the axis of the crucible. The axis of the crucible 221 may be parallel to the axis of the lifting rod 230. In some embodiments, the axis of the crucible 221 may coincide with the axis of the lifting rod 230. The second driving device 260 may include a motor, a hydraulic cylinder, a pneumatic motor, etc.

[0054] In some embodiments, the control system of the scintillation crystal growth apparatus 200 can control the direction and / or speed of movement of the first driving device 250 and / or the second driving device 260.

[0055] In some embodiments, both the lifting rod 230 and the crucible 221 are capable of rotating about their own axes. In some embodiments, the rotation direction of the lifting rod 230 is opposite to that of the crucible 221. The rotation speed of the lifting rod 230 can be 0 rpm-20 rpm, and the rotation speed of the crucible 221 can be 0 rpm-20 rpm. By providing a second driving device 260 to drive the crucible 221 to rotate, the heating of the crucible 221 can be made more uniform, allowing the reaction to proceed fully. In addition, the rotation of the crucible 221 can also make the mass transfer of the molten liquid in the crucible more uniform.

[0056] The furnace body of the scintillation crystal growth apparatus 200 can be either a vacuum furnace 201 or an open furnace 202. A vacuum furnace 201 can be understood as having a completely vacuum interior, ensuring no gas exchange between the equipment inside the furnace and the atmospheric environment. For details on the structure of the vacuum furnace 201, please refer to [link to relevant documentation]. Figure 2B And related explanations. An open furnace 202 can be understood as one where the furnace chamber can be opened, allowing the operator (e.g., a worker) to directly observe the temperature field device 220 inside the furnace. For details on the structure of the open furnace 202, please refer to [link to relevant documentation / instructions]. Figure 2C And related explanations.

[0057] Figure 2B This is a schematic diagram of the structure of a vacuum furnace according to some embodiments of this specification. For example... Figure 2B As shown, the vacuum furnace 201 may include a furnace chamber 210, a lifting rod 230, a first driving device 250, a temperature field device (not shown in the figure), a crucible (not shown in the figure), and a heating device (not shown in the figure). For details regarding the furnace chamber 210, the lifting rod 230, and the crucible, please refer to [link to relevant documentation]. Figure 2A The relevant descriptions will not be repeated here. In some embodiments, the first drive device 250 may include a lifting assembly 251, a rotating assembly 252, and a weighing device 253, and is located at the top of the furnace 210. The first drive device 250 can drive the lifting rod 230 to rotate around the axis of the lifting rod through the rotating assembly 252.

[0058] In some embodiments, the weighing device 253 can be used to detect the weight of the crystal on the lifting rod 230. In some embodiments, the control system of the vacuum furnace can be signal-connected to the weighing device 253 to receive the output signal of the weighing device 253. In some embodiments, the output signal of the weighing device 253 can be the weight signal of the crystal on the lifting rod 230. In some embodiments, the output signal of the weighing device 253 can be output through a mercury slip ring. By receiving the output signal of the weighing device, the control system can determine the weight of the crystal and the rate of increase of the crystal weight, and thus determine the crystallization rate of the crystal. Based on the crystallization rate of the crystal, the control system can further determine the temperature of the temperature field and send a control signal to the power management section of the heating coil to control the temperature of the temperature field; at the same time, the control system can control the movement direction and / or movement speed of the lifting assembly 251 and / or the rotating assembly 252 according to the requirements of the crystal growth process parameters, thereby realizing automatic control of crystal growth.

[0059] In some embodiments, the temperature field device may include a crucible and an alumina tube (not shown in the figure). The alumina tube may be arranged vertically and concentrically outside the crucible to maintain a stable temperature around the crucible and ensure uniform heating of the material in the crucible. In some alternative embodiments, the alumina tube may be replaced by a zirconia tube. In some alternative embodiments, a zirconia tube may be sleeved outside the alumina tube, or an alumina tube may be sleeved outside the zirconia tube, with the alumina tube and zirconia tube arranged concentrically and located outside the crucible. In some alternative embodiments, the zirconia tube may also be replaced by a hollow cylinder composed of zirconia bricks.

[0060] In some embodiments, the heating device may be arranged vertically concentrically with the crucible and the alumina tube, and located outside the alumina tube.

[0061] In some embodiments, the vacuum furnace 201 may include a vacuum device (not shown) to provide a constant pressure vacuum environment inside the furnace chamber 110. For example, a constant pressure vacuum environment of 1000 Pa - 0.5 MPa. In some embodiments, the vacuum device may include a vacuum pump and an inert gas cylinder. By evacuating the furnace chamber with the vacuum pump or by evacuating the furnace chamber with the vacuum pump and then introducing flowing gas to replace the air inside, a constant pressure vacuum environment can be maintained inside the furnace chamber to complete the crystal growth process. In some embodiments, the introduced flowing gas may be one or more of the following: inert gas, carbon monoxide, carbon dioxide, oxygen, etc.

[0062] Figure 2C This is a structural schematic diagram of an open furnace according to some embodiments shown in this specification, such as... Figure 2C As shown, the open furnace 202 may include a furnace frame 229, a furnace chamber 210, a first bottom plate 226, and a moving device 2210.

[0063] The furnace frame 229 is used to mount various components of the open furnace 202, including the furnace chamber 210, the first base plate 226, the motion device 2210, etc. For example, the furnace chamber 210 is disposed on the furnace frame 229, and can be fixed to the furnace frame 229 by means of bolts, welding, or hinges. In some embodiments, the furnace frame 229 has dimensions of 1000mm to 1400mm in length, 750mm to 1000mm in width, and 1100mm to 1800mm in height.

[0064] The furnace chamber 210 can be cylindrical, cubic, or the like, and is used to provide space for crystal growth. In some embodiments, the furnace chamber 210 may include components such as a furnace body and a furnace cover, with the furnace cover positioned above the furnace body.

[0065] In some embodiments, the open furnace 202 may include a temperature field device 220 (see Figure 2D The furnace cover includes components such as a lifting rod assembly and a heat source. A first through-hole may be provided on the furnace cover. This first through-hole can be used to house a temperature field device. In some embodiments, the height of the temperature field device is greater than the height of the furnace cover, meaning a portion of the temperature field device is inside the furnace chamber 210 and a portion is outside the furnace chamber 210. In some embodiments, the height of the temperature field device is not greater than the height of the furnace cover (for example, the upper surface of the temperature field device may be flush with or lower than the furnace cover), meaning the temperature field device is located inside the furnace chamber 210. The temperature field device includes a sealing cylinder, a cover plate disposed at the top of the sealing cylinder, and a base plate disposed at the bottom of the sealing cylinder. A second through-hole is provided on the cover plate. The lifting rod assembly can extend into the temperature field device through the second through-hole. A through-hole for gas passage may also be provided on the cover plate. For a structural description of the temperature field device 220, please refer to [link to relevant documentation]. Figure 2D And its related descriptions.

[0066] In some embodiments, the furnace chamber 210 can be designed as a non-sealed structure, meaning that after the temperature field device 220 is placed into the first through hole provided on the furnace cover, the furnace cover and the outer wall of the temperature field device do not need to be sealed. This design helps to save manufacturing and maintenance costs, ultimately reducing production costs.

[0067] The first base plate 226 is used to support components such as the furnace chamber 210, the temperature field device 220, and the heat source. In some embodiments, the first base plate 226 can be part of the furnace body, that is, the furnace body includes components such as the side wall and the first base plate 226.

[0068] In some embodiments, the motion device 2210 may include a lifting assembly, a weighing assembly, and a rotating assembly. The lifting assembly may be fixed to the furnace frame 229. The lifting assembly may include a first drive device for controlling the up-and-down movement of the lifting rod 230. The weighing assembly may be used to determine the weight of the crystal on the lifting rod assembly. The rotating assembly may be used to control the rotation of the lifting rod.

[0069] Figure 2D This is a schematic diagram of the temperature field device 220 of an open furnace according to some embodiments of this specification.

[0070] In some embodiments, the temperature field device 220 of the open furnace 202 may include a crucible 221, a bottom plate 222, a first cylinder 223, a second cylinder 224, a filler 225, a second cover plate 227, a heating element 228, and an induction coil 2213. In use, the temperature field device can be placed inside the open furnace chamber of the scintillation crystal growth apparatus 200, and is located in the induction coil 2213 inside the furnace. The crucible 221 is placed inside the open furnace chamber, and the heating element 228 is placed directly above the crucible 221.

[0071] A base plate 222 is disposed at the bottom of the aforementioned temperature field device and is used to support other components of the temperature field device, such as the first cylinder 223, the second cylinder 224, and / or the filler 225. In some embodiments, the base plate 222 can be made of a heat-reflective material with a high reflectivity, such as gold, copper, plated metal, stainless steel, etc. In some embodiments, the diameter of the base plate 222 can be 200-500 mm and the thickness can be 10-40 mm. Since the temperature field device is placed inside the furnace of the scintillation crystal growth apparatus 200 during use, the base plate 222 can be placed or mounted on the mounting plate of the furnace body, wherein the mounting method can be welding, riveting, bolting, bonding, etc. During installation, the horizontal level of the base plate 222 is required to be less than 0.5 mm / m. In some embodiments, a circulating coolant passage can be provided on the base plate 222, through which circulating coolant is introduced to absorb heat inside the temperature field device for heat insulation and reduction of heat radiation. The circulating coolant passage can be arranged in a spiral or other shape inside the base plate 222. The coolant used can be water, ethanol, etc., or any combination thereof. The number of circulating coolant passages can be one or more, and the passage diameter can be 5-25 mm.

[0072] The first cylinder 223 is mounted on the base plate 222, forming the outer wall of the temperature field device. The base plate 222 can cover one open end of the first cylinder 223. The first cylinder 223 can be mounted on the base plate 222 by welding, riveting, or other methods to support the entire temperature field device. The first cylinder 223 can be made of materials such as zirconium oxide or graphite. During installation, the concentricity between the first cylinder 223 and the base plate 222 can be less than 1 mm, and the perpendicularity can be less than 0.2 degrees. Based on the size of the base plate 222, the inner diameter of the first cylinder 223 can be 180-450 mm, and the height can be 600-1600 mm.

[0073] The second cylinder 224 can be disposed inside the first cylinder 223. In some embodiments, the second cylinder 224 can be made of materials such as zirconium oxide or alumina. To match the dimensions of the first cylinder 223, the inner diameter of the second cylinder 224 can be 70-300 mm, and the thickness can be 8-30 mm. In some embodiments, one end of the second cylinder 224 can be placed or mounted on the base plate 222, for example, by riveting, snap-fit ​​connection, etc. During installation, the concentricity between the second cylinder 224 and the base plate 222 can be less than 1 mm, and the perpendicularity can be less than 0.2 degrees.

[0074] The filler 225 can be filled inside the second cylinder 224 and / or in the gap between the first cylinder 223 and the second cylinder 224. The filler 225 can be used for heat preservation. In some embodiments, changing the height and tightness of the filler 225 can obtain different stable temperature gradients to meet different crystal growth requirements. The height of the filler 225 determines the location of the heating center and can affect the temperature gradient above the melt interface in the vertical direction. The particle size and tightness of the filler 225 affect its heat preservation ability (the smaller the particle size and the tighter the filling, the stronger the heat preservation ability and the more stable the temperature), and can affect the temperature gradient below the melt interface in the vertical direction. Different filling heights, particle sizes, and tightness correspond to different temperature gradients. In some embodiments, the filler 225 can be a granular, brick-shaped, and / or felt-like substance made of high-temperature resistant material, including zirconium sand (a silicate compound of zirconium), zirconium oxide particles, alumina particles, etc. Its particle size can be 5-200 mesh.

[0075] In some embodiments, the filler 225 inside the second cylinder 224 can be used to support the crucible 221 containing the reaction materials for crystal growth.

[0076] The heating element 228 can be positioned directly above the crucible 221. In some embodiments, the heating element 228 can be used to reduce the temperature gradient above the opening of the crucible 221. The height or inner diameter of the heating element 228 can provide the crystal with the annealing temperature as it passes through the heating element 228 from the seed crystal, thereby achieving simultaneous annealing of the crystal during crystal growth. In some embodiments, the heating element 228 can be made of iridium (Ir), platinum (Pt), or the like. In some embodiments, the outer diameter of the heating element 228 can be 60-260 mm, the inner diameter can be 100-180 mm, the thickness can be 2-10 mm, and the height can be 2-200 mm.

[0077] Crystal growth requires a large temperature gradient, but a large temperature gradient can easily cause crystal cracking. To balance these two factors, a heating element is added above the crucible, which can reduce the temperature gradient above the crucible opening and increase the temperature gradient at the solid-liquid interface.

[0078] In some embodiments, the crucible 221 can be made of iridium (Ir), molybdenum (Mo), etc., with a diameter of 60-250 mm, a thickness of 2-4 mm, and a height of 60-250 mm. In some embodiments, the crucible 221 can serve as a heating element to melt the reactants contained within, facilitating subsequent crystal growth. When an alternating current of a certain frequency is applied to the induction coil (such as induction coil 2213) surrounding the outer wall of the first cylinder 223, an alternating magnetic field is generated around it. Through electromagnetic induction, a closed induced current is generated within the conductor (e.g., crucible 221), and its electrical energy is converted into heat energy, raising the temperature of the conductor and achieving melting. The induction coil 2213 can have 5-14 turns, an induction frequency of 2 kHz-15 kHz, and a rated induction power of 20-60 kW. The inner diameter of the cylinder formed by the induction coil 2213 can be 180-430 mm, and its height can be 180-330 mm. In some embodiments, the filling height of the filler 225 can result in a vertical distance of 0 to 50 mm between the upper edge of the crucible 221 and the upper rear edge of the induction coil 2213. Here, "-" indicates that the upper edge of the crucible is lower than the upper edge of the induction coil, and "+" indicates the opposite. More preferably, the vertical distance between the upper edge of the crucible 221 and the upper edge of the induction coil 2213 is 5 to 45 mm.

[0079] A first cover plate (not shown) is disposed on top of the temperature field device and is used to seal the temperature field device in conjunction with other components. In some embodiments, the first cover plate may cover the other open end of the first cylinder 223 and be connected by welding, riveting, or other methods. In some embodiments, the material of the first cover plate may be the same as that of the base plate 222. In some embodiments, the diameter of the first cover plate may be 200-500 mm and the thickness may be 10-40 mm. In some embodiments, the first cover plate may include at least two first through holes for the passage of a protective gas. In some embodiments, the protective gas may be an inert gas. Inert gases may include nitrogen, helium, radon, etc. Depending on the properties and size of the target crystal being grown, the flow rate of the protective gas introduced into the temperature field device may be 1-30 liters / minute.

[0080] In some embodiments, an observation device (not shown in the figure) may be provided on the first through-hole. Because the crystal growth cycle is very long, reaching 4-40 days, a device is provided above the temperature field device to allow observation of the internal conditions. Users (e.g., factory workers) can observe the crystal growth through this device. If any abnormalities are found, timely remedial action can be taken. The observation device can be a tubular device closed at one end and open at the other. An observation window is provided at the top of the observation device, made of a transparent material such as polystyrene (PS) or polycarbonate (PC).

[0081] In some embodiments, the first cover plate may also be provided with a circulating coolant passage. More details about the circulating coolant passage can be found on the circulating coolant passage on the aforementioned base plate 222.

[0082] The second cover plate 227 is disposed inside the first cylinder 223, covering the opening end of the second cylinder 224 near the first cover plate, and is connected to the second cylinder 224 by welding, riveting, or other means. In some embodiments, in order to clearly obtain the internal situation of the temperature field device from the outside, the second cover plate 227 may also have a second through hole corresponding to the first through hole on the first cover plate. In some embodiments, the thickness of the second cover plate 227 may be 20-35 mm.

[0083] A sealing ring (not shown) and a pressure ring (not shown) can achieve a seal between the first cylinder 223 and the first cover plate. In some embodiments, the sealing ring can be used at the connection between the first cylinder 223 and the first cover plate, and it can be made of a material with a certain degree of elasticity, such as silicone or rubber. In some embodiments, the inner diameter of the sealing ring can be 170-540 mm, and the wire diameter can be 5-10 mm.

[0084] The pressure ring provides fixation and compression to the sealing ring. In some embodiments, the shape of the pressure ring may match that of the first cylinder 223, and its inner diameter may be slightly larger than the outer diameter of the first cylinder 223. This allows the pressure ring to fit over the first cylinder 223 and be movable. In some embodiments, the outer diameter of the pressure ring may be 200-500 mm, the inner diameter may be 190-460 mm, and the thickness may be 8-15 mm.

[0085] In some embodiments, the temperature field device may further include a gas channel (not shown in the figures). The gas channel may be disposed on the observation element and is used to connect a vent pipe and / or an outlet pipe to introduce a protective gas into the interior of the temperature field device. More information about protective gases can be found at [link to relevant documentation]. Figure 3 And its related descriptions.

[0086] After being weighed and pretreated according to the reaction formula, the raw materials required for crystal growth can be placed in crucible 221 for reaction. Different crystals require different growth conditions, such as different temperature gradients. The amount and density of the filler 225 can be adjusted to achieve the desired temperature gradient. For example, the amount of filler 225 determines the relative position of crucible 221 and induction coil 2213, which in turn determines the heating center of the entire temperature field. Simultaneously, a higher density of the filler 225 results in better heat retention, better stability of the formed temperature field, and is more conducive to crystal growth. After determining the amount, particle size, and density of the filler 225, other components are assembled and sealed. After all components are assembled, gas can be introduced into the temperature field device, and auxiliary equipment such as a cooling circulation pump can be started to introduce coolant into the circulating coolant passages in the base plate 222 and the first cover plate. Then, the scintillation crystal growth apparatus 200 (including the temperature field device) can be started to begin crystal growth. Gas introduced into the temperature field device can enter through one or more first through-holes (e.g., it can first enter through one or more gas channels). Gas discharged from the temperature field device can be discharged through the remaining first through-holes (e.g., it can last exit through one or more gas channels). After the temperature is suitable, the automatic control program can be started to enter the automatic growth mode. After processes such as necking, shoulder formation, equal diameter formation, tailing, and cooling, the scintillation crystal growth is completed after several days (e.g., 4-40 days).

[0087] Understandably, crystal growth requires a large temperature gradient, but a large temperature gradient can easily cause crystals to crack.

[0088] The scintillation crystal growth apparatus provided in some embodiments of this specification employs an open furnace and a flowing atmosphere heat exchange temperature field device. While increasing the temperature gradient at the solid-liquid interface, a post-heater is added above the crucible opening to reduce this temperature gradient. This effectively solves the problem of high crystal stress and easy cracking caused by poor temperature field symmetry and unsuitable temperature gradient during crystal growth, thus providing a good growth environment for scintillation crystal growth. In addition, by suppressing SiO2 volatilization through temperature field airflow pressure and allowing oxygen to enter the furnace, the problem of poor crystal performance consistency caused by composition deviation during growth and the problem of oxygen vacancies formed by oxygen deficiency during vacuum furnace growth can be alleviated.

[0089] Figure 3 This is an exemplary flowchart of a scintillation crystal growth method according to some embodiments of this specification. In some embodiments, process 300 may be performed by a scintillation crystal growth apparatus 200. Figure 3 As shown, process 300 may include the following steps.

[0090] Step 310: Weigh each reactant according to the molar ratio based on the reaction equation.

[0091] The reaction equation of the scintillation crystal is as follows: Among them, x = 0.0000001 - 0.06, 0 < s < 0.05, 0 ≤ y < 1, 0 ≤ z < 1, 0 < n < 10. For more information about x, y, z, s, and n, reference can be made to Figure 1 and its related descriptions.

[0092] In some embodiments, before weighing each reaction material, a first pretreatment is performed on each reaction material in the reaction equation.

[0093] In some embodiments, the first pretreatment may include high-temperature roasting. It can be understood that in order to remove other substances contained in the reaction materials as much as possible, such as water and organic substances of other metal elements (including cerium, gallium, aluminum, gadolinium, etc.), to make the reaction materials purer, all reaction raw materials can be separately subjected to high-temperature roasting to achieve the purpose of removing water and other organic substances. Commercially available high-temperature roasting equipment can be used to roast the reaction materials, such as a muffle furnace. In some embodiments, the roasting temperature of the reaction materials can be 100°C - 1400°C. Depending on the properties of different reaction materials, the high-temperature roasting time can be not less than 5 hours.

[0094] The purity of the reaction materials has a great impact on the scintillation performance of the scintillation crystal. Therefore, in order to make the finally obtained scintillation crystal meet the requirements, the purity of CeO2 and Lu2O3 in the reaction materials used for growing the scintillation crystal can be greater than 99.99%, and the purity of SiO2 and Y2O3 in the reaction materials can be greater than 99.999%.

[0095] In some embodiments, after performing the first pretreatment on each reaction material in the reaction equation, when the reaction material naturally cools to 35°C, weighing instruments such as an analytical balance and a macro analytical balance can be used to weigh the reaction materials according to the molar ratio.

[0096] It can be understood that during the crystal growth process, silicon dioxide (SiO2) is prone to volatilization under heating conditions, which may cause the composition of the finally formed crystal to deviate, and at the same time result in different compositions of the crystals obtained each time and poor repeatability. In some embodiments, the actual weight of silicon dioxide exceeds the theoretical weight of silicon dioxide by 0.001% - 10%. The actual weight can refer to the actually weighed weight, and the theoretical weight can refer to the weight calculated based on the aforementioned molar ratio, that is, after weighing silicon dioxide according to the molar ratio, an additional 0.001% - 10% of the already weighed weight is added in excess. By adding an excessive amount of silicon dioxide reaction material, the problems of composition deviation and poor growth repeatability caused by raw material volatilization can be inhibited to a certain extent.

[0097] In some embodiments, a second pretreatment of the weighed reactants is also required.

[0098] In some embodiments, the second pretreatment may include mixing the reactants at room temperature. In other embodiments, the second pretreatment may include heating the reactants to a preset temperature and then mixing the heated reactants.

[0099] Understandably, uniformly mixed reactants are beneficial for subsequent crystal growth. The mixing equipment used can be a three-dimensional motion mixer, a double cone mixer, a vacuum mixer, a plow mixer, a V-type mixer, a conical twin-screw mixer, a planetary mixer, a horizontal screw mixer, etc.

[0100] In some embodiments, the reactants can be mixed uniformly at room temperature using a mixing device; or the reactants can be heated to a preset temperature and then mixed uniformly. The preset temperature can be less than 1200°C. The mixing time of the reactants can be 0.5-48 hours.

[0101] In some embodiments, the second pretreatment may include pressing. Pressing refers to applying pressure to the reactants to transform them from a dispersed state into a preform with its original shape, such as a cylinder. Pressed reactants have a smaller volume than their dispersed form, making them easier to place into the reaction site, such as a reaction vessel, facilitating the loading of reactants in one go. Simultaneously, pressing removes air contained within the dispersed reactants, preventing it from affecting crystal growth in subsequent reactions. The equipment used for pressing can be an isostatic press, such as a cold isostatic press. The reactants can be placed in a pressing tank and then pressed into shape. The pressure used during pressing can be 100-300 MPa.

[0102] After a first pretreatment of each reactant in the reaction equation, the reactants are weighed according to their molar ratio. A second pretreatment is then performed on the weighed reactants. Using the upward pulling method to grow scintillation crystals, large-sized crystals with few macroscopic defects can be generated. These crystals possess excellent optical properties, crystal growth repeatability, and crystal performance consistency, making them widely applicable in various fields. Introducing a protective gas improves the temperature gradient of the temperature field and reduces volatile contamination of the melt, decreasing the possibility of iridium volatilization into the melt and improving the stability of crystal growth. Using an appropriate excess of SiO2 avoids deviations in the scintillation crystal composition, effectively solving the problem of Ce doping concentration deviations under different process conditions, resulting in good crystal growth repeatability. Optimizing the process parameters during crystal growth ensures consistent quality in each crystal growth.

[0103] Step 320: Grow scintillation crystals using the uplift method.

[0104] In some embodiments, a scintillation crystal can be grown using a scintillation crystal growth apparatus 200. Further descriptions of single crystal growth furnaces and temperature field devices can be found in [reference needed]. Figures 2A-2D And its related descriptions.

[0105] In some embodiments, the assembly process of the scintillation crystal growth apparatus 200 needs to be completed before crystal growth can be performed.

[0106] In some embodiments, the assembly process may include pre-assembly treatment of at least one component of the crystal growth apparatus. In some embodiments, at least one component of the aforementioned crystal growth apparatus may include a crucible. In some embodiments, the pre-assembly treatment may include one or more of coating protection, acid immersion, and foreign matter cleaning. Coating protection treatment may refer to applying a high-temperature coating material, such as polyamide silicone, to the entire outer surface of the crucible. The crucible treated with coating protection can isolate or reduce the contact between oxygen and the crucible surface, thereby avoiding or reducing the impact of crucible oxidation and its oxides on the crystal during crystal growth in a high-temperature, oxygen-rich environment. In some embodiments, after coating protection treatment, the crucible may also be subjected to acid immersion treatment. For example, the inner wall of the crucible may be immersed in acid. In some embodiments, the acid may include organic acids and / or inorganic acids. Exemplary organic acids may include one or more of carboxylic acids (e.g., formic acid, oxalic acid, etc.), sulfonic acids (e.g., ethanesulfonic acid, benzenesulfonic acid, etc.), and sulfinic acids. Exemplary inorganic acids may include one or more combinations of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. In some embodiments, the concentration of the acid may be 1%-15%. The acid immersion treatment can last from 0.1 to 10 hours. After immersion, the crucible can be rinsed with pure water and dried. Foreign matter cleaning refers to removing foreign objects from the crucible and wiping it with medical alcohol. Once the pre-assembly treatment of the crucible is completed, installation can proceed.

[0107] In some embodiments, with Figure 2C Taking the open furnace shown as an example, the assembly process may include installing a temperature field device, and the steps include, but are not limited to: Step 1: Install the base plate 222 onto the mounting aluminum plate of the crystal growth furnace, and adjust the level of the base plate 222 to a level of 0.02 mm / m; Step 2: Install the second cylinder 224 on the base plate 222 and adjust the concentricity and perpendicularity between them. The concentricity of the second cylinder 224 and the base plate 222 should be less than 0.5 mm, and the perpendicularity should be less than 0.2 degrees. Step 3: Install the first cylinder 223 on the base plate 222 and adjust the concentricity and perpendicularity between them. The concentricity of the first cylinder 223 and the base plate 222 should be less than 0.5 mm, and the perpendicularity should be less than 0.2 degrees. After installation, use high-temperature adhesive to seal the connection between the first cylinder 223 and the base plate 222 to ensure positive pressure and no air leakage. Step 4: Fill the gap between the first cylinder 223 and the second cylinder 224 and the bottom of the second cylinder 224 with filler 225, and determine the amount and tightness of the filler according to the growth conditions of the crystal to be grown. Step 5: Place the crucible 221 on the filler 225 at the bottom of the second cylinder 224. The vertical distance between the upper edge of the crucible 221 and the upper edge of the induction coil 2213 is -20 to 6 mm. The vertical distance can be changed according to the growth conditions of the crystal to be grown. Step 6: Install the heating element 228 above the crucible 221; Step 7: Install the second cover plate 227 above the second cylinder 224, and adjust the concentricity of the second cover plate 227 with the first cylinder 223 and the second cylinder 224; Step 8: Install the pressure ring and the sealing ring coated with vacuum grease; Step 9: Install the first cover plate above the first cylinder 223 and adjust the concentricity between them to ensure that the first through hole on the first cover plate is on the same axis as the corresponding second through hole on the second cover plate 227. Connect the pressure ring and the first cover plate by thread, and tighten the sealing ring to achieve a seal and ensure positive pressure without leakage; Step 10: Install the observation piece on the first cover plate and connect the vent / exhaust pipe to the gas channel. The entire temperature field device is now installed.

[0108] In some embodiments, the assembly process may include sealing the scintillation crystal growth apparatus 200 and then introducing a protective gas into it. Sealing can be achieved by using sealing rings, vacuum grease, or other sealing materials at the joints between the various components of the crystal growth apparatus.

[0109] Understandably, a suitable protective gas can, to some extent, suppress the volatilization of reactants (e.g., SiO2), thereby reducing the occurrence of crystal composition deviation problems during crystal growth. In some embodiments, a protective gas can be introduced into the sealed scintillation crystal growth apparatus 200 (e.g., the temperature field device). The protective gas can refer to a gas that enters from one inlet and exits from another outlet of the scintillation crystal growth apparatus 200. In some embodiments, the protective gas can be an inert gas. It should be noted that the inert gas used in this application can include nitrogen (N2), argon (Ar), etc. To ensure that the introduced protective gas does not affect the reactants, for example, by introducing other impurities, the purity of the protective gas can be greater than 99.9%. In some embodiments, when the protective gas is introduced into the crystal growth apparatus, its flow rate can be 1-30 liters / minute.

[0110] As shown in the table below, when the flow rate of the protective gas is 1-30 liters / minute, the scintillation crystal has a higher light output, meaning it has better scintillation performance.

[0111] like Figure 4 As shown, the scintillation crystal, after being fully oxidized (i.e., when the flow rate of the protective gas is 0), is yellow overall and has a low light output.

[0112] By introducing a protective gas into the crystal growth apparatus, the protective gas is set to be an inert gas, and the flow rate of the protective gas is 1. A flow rate of 30 liters per minute can reduce the oxidation level of the scintillation crystal during crystal growth and regulate the Ce content in the scintillation crystal. 3+ and / or Ce 4+ The proportion of this makes the generated scintillation crystal appear colorless and transparent (e.g., Figure 1 As shown in the figure, it has higher light output and better flicker performance.

[0113] In some embodiments, after the assembly process of the scintillation crystal growth apparatus 200 is completed, the scintillation crystal growth apparatus 200 can be started to grow scintillation crystals using the pull-up method. Starting the scintillation crystal growth apparatus 200 may include energizing and / or circulating a coolant (e.g., water). The reactants need to be melted by heating before crystal growth can proceed. The induction coil in the scintillation crystal growth apparatus 200, when energized, can heat the crucible to melt the reactants contained within. In some embodiments, the melting time of the reactants during crystal growth is 5-48 hours. It should be understood that the high temperature required during crystal growth (e.g., 1900°C) will generate a large amount of heat radiation to the outside. Furthermore, excessively long crystal growth times (e.g., 4-40 days) will affect the performance of the crystal growth apparatus due to prolonged high-temperature radiation. Therefore, a circulating coolant is used to reduce heat radiation. The coolant used can be water, ethanol, ethylene glycol, isopropanol, n-hexane, or any combination thereof; for example, it can be a 50:50 mixture of water and ethanol.

[0114] The upward pulling method can include processes such as melting, preheating seed crystals, seeding, temperature adjustment, necking, shoulder formation, equal diameter formation, tailing, cooling, and crystal extraction.

[0115] The melt refers to the material that has been heated to a specific temperature through a certain heating process, causing the reactants to completely melt and form a melt, while maintaining a suitable temperature (i.e., temperature gradient) within the scintillation crystal growth apparatus. Since the crucible acts as the heating element within the scintillation crystal growth apparatus, heat radiates from the crucible to the surrounding area, creating a temperature gradient within the apparatus. The temperature gradient can be defined as the rate of change of temperature from a point within the scintillation crystal growth apparatus 200 towards a neighboring point; it can also be called the rate of change of temperature per unit distance. For example, if the temperature change between point A and point B is T1-T2, and the distance between the two points is r1-r2, then the temperature gradient from point A to point B is ΔT = T1-T2 / r1-r2. A suitable temperature gradient is necessary for the growth of the scintillation crystal. For instance, only when the vertical ΔT is sufficiently large can the latent heat of crystallization generated during growth be dissipated in time, maintaining stable growth. Simultaneously, the melt temperature below the growth interface must be higher than the crystallization temperature to prevent localized rapid growth of the scintillation crystal, ensuring a stable growth interface and guaranteeing stable growth. Maintaining a suitable temperature gradient can be determined by the location of the heating center. The heating center during melting influences the determination of the temperature gradient.

[0116] In some embodiments, during the heating and melting process, heating can be stopped when the diameter of the polycrystalline material formed by the melting and subsequent solidification of the reactants reaches 50 mm. After heating is complete, the temperature can be held for 0.5-1 hour or 0.2-1 hour, and heating or cooling can continue depending on the melting status of the reactants. The upper limit of the heating can be determined based on the temperature or heating power (e.g., the power of the induction coil) at the start of the last scintillation crystal growth using the scintillation crystal growth apparatus 200. For example, the output power of the intermediate frequency power supply can be appropriately adjusted to 50-300 watts, or the heating power can be 300-500 watts less than the heating power at the start of the last pulling. The heating rate can be determined based on the quotient between the temperature at the start of the last pulling and the time (e.g., 24 hours). After heating is complete, the temperature can be held for 0.5-1 hour, and heating or cooling can continue depending on the melting status of the reactants.

[0117] Preheating the seed crystal refers to fixing the seed crystal to the top of the lifting rod and slowly lowering it into the temperature field during the heating and melting process, so that its own temperature is close to that of the melt. This prevents the overcooled seed crystal from cracking upon contact with the melt during subsequent operations. During preheating, the seed crystal is kept at a distance from the upper surface of the reactant. Preferably, the distance is 5-100 mm. In some embodiments, the diameter of the seed crystal used can be 4 mm. 12 mm. When preheating the seed crystal, the seed crystal can be lowered at a speed of 50-800 mm / hour.

[0118] The next step can refer to lowering the lifting rod to bring the seed crystal into contact with the melt after the reactant has melted to a diameter smaller than the set value or has completely melted to form a melt.

[0119] Temperature adjustment refers to adjusting the current temperature within the scintillation crystal growth apparatus to a suitable temperature for scintillation crystal growth. During temperature adjustment, the seed crystal needs to be lowered again by 0.5-2 mm. In some embodiments, the temperature adjustment rate can be 100-300 watts / 0.1 hours. After the temperature adjustment process is completed, the temperature inside the scintillation crystal growth apparatus can be maintained at 1950℃-2100℃ for 0.2-2 hours. After completion, the lead screw can be rotated to pull the lifting rod upwards. After the seed crystal passes through the second cover plate and throughout the subsequent scintillation crystal growth process, the rotation speed of the lifting rod can be 0.01-35 revolutions per minute.

[0120] Necking refers to the process of slowly increasing the temperature so that the temperature at the zero point of the melt (the center point of the liquid surface in the crucible) is slightly higher than the melting point of the scintillation crystal. This allows the newly grown scintillation crystal to gradually decrease in diameter during the growth process of rotating and pulling the seed scintillation crystal. Necking can reduce the excessive extension of dislocations from the seed crystal to the single crystal below the neck.

[0121] Shoulder formation refers to the process where, as atoms or molecules at the solid-liquid interface between the seed crystal and the melt begin to align according to the seed crystal's structure, the temperature of the temperature field is slowly reduced based on the real-time growth rate of the scintillation crystal, causing the seed crystal to expand at a predetermined angle. In some embodiments, the shoulder angle can be 30-70 degrees. The shoulder length can be 40-130 mm.

[0122] Equal diameter refers to the growth of a scintillation crystal into a rod-shaped structure of equal diameter according to a predetermined diameter achieved during the shoulder formation process. In some embodiments, the equal diameter length of the scintillation crystal growth can be 10-200 mm.

[0123] Tailing out can refer to the process of raising the scintillation crystal after it has grown to a predetermined length until it is completely separated from the melt. Tailing out can be the reverse operation of shoulder placement. This is achieved by changing the rising speed of the lifting rod to reduce the diameter of the scintillation crystal until it separates from the melt, or by reducing the diameter of the scintillation crystal to a preset value. In some embodiments, the tailing angle can be 30-70 degrees. The tailing length can be 40-110 mm.

[0124] Cooling refers to the slow cooling process after the growth process is completed to eliminate the stress formed in the scintillation crystal during high-temperature growth and prevent cracking caused by a sudden temperature drop. In some embodiments, the cooling time for the scintillation crystal can be 20-100 hours. In some embodiments, assuming T is the temperature after the growth process is completed, the temperature drop rate of the scintillation crystal during the cooling process can be T / (20-100) hours. In some embodiments, the temperature drop rate of the scintillation crystal can be 15-95°C / hour. The scintillation crystal growth ends when the output heating power (e.g., the heating power of the induction coil) is 0.

[0125] Crystal removal refers to opening the scintillation crystal growth apparatus and taking out the grown scintillation crystal when the internal temperature drops to room temperature. Throughout the scintillation crystal growth process, the growth rate can range from 0.01 to 6 mm / hour, depending on the settings of various process parameters at different stages. More preferably, the growth rate is 0.1 to 6 mm / hour. The resulting scintillation crystal diameter can be 50 to 115 mm.

[0126] In some embodiments, the resulting scintillation crystal can have a diameter ≥ 70 mm, for example 70-115 mm. The constant diameter length can be ≥ 130 mm, for example 130-200 mm.

[0127] In some embodiments, the weight of the generated scintillation crystal is no more than 70% of the weight of the melt.

[0128] By limiting the ratio of the weight of the scintillation crystal to the weight of the melt generated in the scintillation crystal, the crystal yield can be increased.

[0129] In some embodiments, the generated scintillation crystal contains at least 5 ppm of cerium trivalent rare earth elements. The mass ratio of Ca to Ce in the scintillation crystal is less than 0.4.

[0130] In some embodiments, the generated scintillation crystal has few macroscopic defects such as cracks and inclusions. Tests show that the crystal density can reach 7-7.4 g / cm³; the light emission center wavelength can reach 350-340 nm; the light output can reach 35000 ph / MeV or higher; the energy resolution can be ≤9%; and the decay time can be as low as 35 ns or less. Its excellent overall performance makes it a promising candidate for applications in nuclear medicine, industrial CT, security inspection, and environmental monitoring.

[0131] In some embodiments, one or more steps in the scintillation crystal growth process can be controlled by a PID (proportional, integral, differential) controller, including but not limited to necking, shoulder formation, constant diameter formation, tailing, and cooling processes. In some embodiments, the PID parameter can be 0.1-5. More preferably, the PID parameter can be 0.5-4.5. More preferably, the PID parameter can be 1-4. More preferably, the PID parameter can be 1.5-3.5. More preferably, the PID parameter can be 2-3. More preferably, the PID parameter can be 2.5-3.5.

[0132] The scintillation crystal growth method will be described in detail below through Examples 1-5. It should be noted that the reaction conditions, reactants, and amounts of reactants in Examples 1 and 5 are only for illustrating the scintillation crystal growth method and do not limit the scope of protection of this application.

[0133] Example 1 Scintillation crystals were grown using the aforementioned scintillation crystal growth apparatus. The growth. According to Figure 3 Steps 1-5 of the temperature field device installation process are performed to install the temperature field device. The reactant material with a purity of 99.9999% is then calcined at 1000 degrees Celsius (the calcination temperature) for 5 hours, followed by natural cooling to room temperature (35°C). Take it out at C. Weigh the reactants according to the molar ratio of each reactant in the reaction equation. The aforementioned reaction equation can be found in [reference needed]. Figure 3 And its related descriptions.

[0134] Where x=0.0016, y=0.02, s=0.0002, z=0.1, SiO2 is in excess by 0.3% of its own weight, and other raw materials are weighed according to the stoichiometric ratio in the chemical equation. After weighing, all raw materials are placed in a three-dimensional mixer and mixed for 1 hour (i.e., mixing time). Then, they are removed and placed in a pressing mold and pressed into cylindrical blocks using a cold isostatic press at a pressure of 200 MPa. The material is then loaded into a 150 mm diameter mold. An iridium crucible with an inner height of 150 mm is placed inside the installed temperature field device, and the concentricity of the iridium crucible and the temperature field device is adjusted. The crucible position is set to +20 mm. The concentricity of the iridium crucible 214, heating element 228, second cover plate 227, first cover plate, and weighing guide rod is adjusted sequentially, ensuring a seal between the first cover plate and the first cylinder 223. After assembling the observation piece on the first cover plate, protective gas N2 and circulating coolant are introduced into the temperature field device. The crystal growth parameters are set as follows: crystal diameter 80 mm, shoulder length 95 mm, constant diameter length 180 mm, tail length 30 mm, heating time 24 hours, rotation speed 10 rpm, pulling speed 2 mm / h, cooling time 60 hours, PID value 0.5, and crystal density 7.15 g / cm³. After setting the parameters, place the Ce:Ca:L(Y / SC)SO seed crystal on the top of the lifting rod and adjust the concentricity of the seed crystal and the first cover plate. Initiate melting by heating, while simultaneously lowering the seed crystal slowly for preheating. To prevent seed crystal cracking, maintain a distance of 5-15 mm between the seed crystal and the melt surface. Once melting is complete, slowly lower the seed crystal to contact the melt and adjust the temperature. During temperature adjustment, lower the seed crystal by 0.5-2 mm to ensure complete melting of the seed crystal and melt, maintaining a complete interface and reducing crystal cracking caused by the crystal's growth point during later cooling. Once the temperature is suitable, start the automatic control program to enter automatic growth mode. Following processes such as necking, shoulder formation, equal diameter formation, tailing, and cooling, crystal growth is completed after 15 days (i.e., the growth time).

[0135] like Figure 5 As shown, the scintillation crystal generated in this embodiment exhibits the following performance characteristics: the crystal is colorless, has a normal shape matching the designed shape, a rough surface with slight remelting lines, and after removing the beginning and end and polishing, the crystal is internally transparent. X-ray irradiation reveals no point scattering, and there are no macroscopic defects such as cloudiness or inclusions. Testing revealed that the luminescence center wavelength of this scintillation crystal is 420 nm; the light output is 35200 ph / MeV; and the decay time is ≤37 nanoseconds.

[0136] Example 2 The specific steps and methods are as described in Example 1. It should be noted that the following parameters have been adjusted: The grown scintillation crystal is Where x=0.0016, s=0.0008, z=0.15, n=1; calcination temperature 1200℃, mixing time 1-6 hours, iridium crucible diameter 180 mm. The internal height is 180 mm, the protective gas used is argon (Ar), the crystal diameter is set to 105 mm, the shoulder length is set to 105 mm, the constant diameter length is set to 150 mm, the tail length is set to 70 mm, the pulling speed is set to 1.5 mm / hour, the cooling time is set to 100 hours, the crystal density is 7.1 g / cm³, the seed crystal is LYSO, and the growth time is 18 days.

[0137] like Figure 6 As shown, the scintillation crystal generated in this embodiment exhibits the following performance characteristics: the crystal is white, with a normal shape matching the intended design. The crystal surface is rough with obvious remelting lines. After removing the beginning and end and polishing, the crystal is internally transparent. X-ray irradiation reveals no point scattering, and there are no macroscopic defects such as cloudiness or inclusions. Testing revealed that the scintillation crystal has a light emission center wavelength of 420 nm; a light output of 35300 ph / MeV; an energy resolution ≤9%; and a decay time ≤36 nanoseconds.

[0138] Example 3 The specific steps and methods are as described in Example 1. It should be noted that the following parameters have been adjusted: The grown scintillation crystal is Where x=0.0016, s=0.0003, n=1, calcination temperature 1200℃, mixing time 1-6 hours, iridium crucible diameter 180 mm. The internal height is 180 mm, the protective gas used is Ar, the crystal diameter is set to 90 mm, the shoulder length is set to 85 mm, the constant diameter length is set to 160 mm, the tail length is set to 70 mm, the pulling speed is set to 1.5 mm / hour, the cooling time is set to 100 hours, the crystal density is 7.15 g / cm³, the seed crystal is LYSO, and the growth time is 18 days.

[0139] like Figure 1 As shown, the scintillation crystal generated in this embodiment exhibits the following performance characteristics: the crystal is white, with a normal shape matching the intended design. The crystal surface is rough with obvious remelting lines. After removing the beginning and end and polishing, the crystal is internally transparent. X-ray irradiation reveals no point scattering, and there are no macroscopic defects such as cloudiness or inclusions. Testing revealed that the scintillation crystal has a light emission center wavelength of 420 nm; a light output of 35400 ph / MeV; an energy resolution ≤9%; and a decay time ≤35 nanoseconds.

[0140] Example 4 The specific steps and methods are as described in Example 1. It should be noted that the following parameters have been adjusted: The grown scintillation crystal is Where x=0.0016, y=0.05, s=0.0003, z=0.1, n=1, calcination temperature 1200℃, mixing time 1-6 hours, iridium crucible diameter 180 mm. The internal height is 180 mm, the protective gas used is N2, the crystal diameter is set to 90 mm, the shoulder length is set to 85 mm, the constant diameter length is set to 160 mm, the tail length is set to 70 mm, the pulling speed is set to 1.5 mm / hour, the cooling time is set to 100 hours, the crystal density is 7.1 g / cm³, the seed crystal is LYSO, and the growth time is 18 days.

[0141] like Figure 7 As shown, the scintillation crystal generated in this embodiment exhibits the following performance characteristics: the crystal is white, with a normal shape matching the intended design. The crystal surface is rough with obvious remelting lines. After removing the beginning and end and polishing, the crystal is internally transparent. X-ray irradiation reveals no point scattering, and there are no macroscopic defects such as cloudiness or inclusions. Testing revealed that the scintillation crystal has a light emission center wavelength of 420 nm; a light output of 35400 ph / MeV; an energy resolution ≤9%; and a decay time ≤35 nanoseconds.

[0142] Example 5 The specific steps and methods are as described in Example 1. It should be noted that the following parameters have been adjusted: The grown scintillation crystal is Where x=00016, s=0.0003, z=0.1, n=2, calcination temperature 1200℃, mixing time 1-6 hours, iridium crucible diameter 180 mm. The internal height is 180 mm, the protective gas used is N2 with a flow rate of less than 15 liters / minute, the crystal diameter is set to 90 mm, the shoulder length is set to 85 mm, the constant diameter length is set to 160 mm, the tail length is set to 70 mm, the pulling speed is set to 1.5 mm / hour, the cooling time is set to 100 hours, the crystal density is 7.1 g / cm³, the seed crystal is LYSO, and the growth time is 18 days.

[0143] like Figure 8 As shown, the scintillation crystal generated in this embodiment exhibits the following performance characteristics: the crystal is white, with a normal shape matching the intended design. The crystal surface is rough with obvious remelting lines. After removing the beginning and end and polishing, the crystal is internally transparent. X-ray irradiation reveals no point scattering, and there are no macroscopic defects such as cloudiness or inclusions. Testing revealed that the scintillation crystal has a light emission center wavelength of 420 nm; a light output of 35300 ph / MeV; an energy resolution ≤9%; and a decay time ≤35 nanoseconds.

[0144] In the above embodiments, the crystal growth repeatability and performance repeatability are excellent, mainly due to the improved uniformity of the overall temperature field. By adjusting the dimensions of each component in the temperature field, the relative position of the crucible in the temperature field, and the post-heater above the crucible (if necessary), the optimal temperature field or temperature gradient required for crystal growth can be obtained. By suppressing SiO2 volatilization and implementing compensation measures, optimizing the growth process and parameters (such as the matching of pulling speed, rotation speed and crystal diameter), optimizing process conditions, crystal growth time, crystal weight, and adjusting the Ce doping concentration and SiO2 compensation amount, scintillation crystals with large crystal diameters, good optical properties, and good growth and performance repeatability were obtained.

[0145] The embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention are considered equivalent substitutions and are included within the protection scope of the present invention.

[0146] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0147] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0148] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although some inventive embodiments that are currently considered useful have been discussed by way of various examples in the foregoing disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments described herein.

[0149] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0150] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0151] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0152] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A scintillation crystal, characterized in that, The molecular formula of the scintillation crystal is shown below: Wherein, X is composed of Ce, M is composed of one or more of Ca, Mg, Sr, Mn, Ba, Al, Fe, Re, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Tm, Lu, and Sc, and M includes at least one of Ca and Mg, Q is composed of O, N is composed of one or more of Cl, F, Br, and S, and N includes at least Cl; x = 0.0000001 - 0.06, m = 0 - 0.06, 0 ≤ z < 1, 0 < n < 10; When preparing the scintillation crystal, a first dopant and a second dopant are added. The first dopant is a compound containing Ce, and the second dopant is a compound containing M.

2. The scintillation crystal according to claim 1, characterized in that, X is composed of Ce, M is composed of Ca or M is composed of Ca and Sc, Q is composed of O, and N is composed of Cl. The crystal has the following molecular formula: ,in, 0 < s < 0.05, 0 ≤ y < 1, and the ratio of the mass of Cl to the sum of the masses of Lu, Ce, Sc, and Y is 0.01 ppm - 1000 ppm.

3. The scintillation crystal according to claim 2, characterized in that, The mass ratio of Ca to Ce in the scintillation crystal does not exceed 300.

4. The scintillation crystal according to claim 1, wherein the mass ratio of Ce to rare earth elements in the first dopant is at least 10 ppm; the mass ratio of M to rare earth elements in the second dopant is 0.1 ppm - 500 ppm.

5. A method for growing a scintillation crystal, characterized in that, For growing the scintillation crystal according to any one of claims 1 - 5; The reaction equation for generating the scintillation crystal is: Where x = 0.0000001 - 0.06, 0 <s<0.05,0≤y<1,0≤z<1,0<n<10; The method includes: weighing each reaction material according to the molar ratio based on the reaction equation; Growing the scintillation crystal using the upward pulling method.

6. The method according to claim 5, characterized in that, Based on the reaction equation, growing the scintillation crystal using the upward pulling method includes: Before weighing each reaction material, performing a first pretreatment on each reaction material in the reaction equation; Performing a second pretreatment on the weighed reaction materials; Growing the scintillation crystal using the upward pulling method.

7. The method according to claim 6, characterized in that, The first pretreatment includes high-temperature roasting at 100°C - 1400°C; The second pretreatment includes mixing the reaction materials at room temperature; or, The second pretreatment includes heating the reaction materials to a preset temperature and mixing the heated reaction materials.

8. The method according to claim 6, characterized in that, The growing the scintillation crystal using the upward pulling method includes: A protective gas, which is an inert gas, is introduced into the crystal growth apparatus at a flow rate of 1. 30 liters / minute.

9. The method according to claim 5, characterized in that, The ratio of the weight of the generated scintillation crystal to the weight of the melt does not exceed 70%.

10. A scintillation crystal growth apparatus, characterized in that, For generating the scintillation crystal according to any one of claims 1 - 5; the scintillation crystal growth device includes a furnace chamber, a temperature field device, a lifting rod, a heating device, and a first driving device; The temperature field device and the heating device are provided in the furnace chamber; At least a part of the lifting rod is located in the furnace chamber; The first driving device is connected to the lifting rod to drive the lifting rod to move along the axial direction of the lifting rod.

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