Crucible assembly including ratio of gasket size to crucible size and ingot size in scintillator fabrication
By optimizing the ratio of the washer size of the crucible assembly to the crucible and ingot ratio, the problems of heat loss and uneven crystal growth in traditional crucible assembly are solved, and high-quality single crystal ingot growth under steady-state temperature conditions are achieved.
Patent Information
- Application Number
- CN202410236166.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-01
- Publication Date
- 2025-09-02
AI Technical Summary
Traditional crucible components fail to effectively consider the dimensional relationship between crucible, washer and ingot, resulting in heat loss, poor thermal control, uneven crystal growth, and deformation and rupture of ingots.
By optimizing the ratio of the washer size to the crucible size and the ingot size, the target ratio parameter Z is set to suppress heat loss, promote the uniformity of the crystal structure and composition uniformity, and avoid damage and deformation of the ingot.
Maintaining steady-state temperature conditions in the crucible is achieved, improving the maintenance and fidelity of the composition and structure of single crystal ingots, and promoting the uniformity and quality of crystal growth.
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Figure CN120575326A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates generally to crystal growth for nuclear medicine imaging, and in particular to scintillator fabrication and crystal growth. Background Art
[0002] The Czochralski crystal growth process (often shortened to "Czochralski method" or "CZ method") is a widely used process for producing bulk crystals used in a variety of electronic and optical devices. The Czochralski crystal growth process begins by inserting a small seed crystal into a melt placed in a crucible. The crucible is then placed in a fabrication chamber, often called a "furnace chamber," which heats the crucible as the seed crystal interacts with the melt. The seed crystal is then gradually pulled upward, or "pulled," out of the crucible to form a single crystal ingot (boule). Summary of the Invention
[0003] According to a non-limiting embodiment, a crucible assembly includes a crucible and an annular gasket. The crucible includes a body defining an interior volume configured to grow an ingot having an ingot diameter (Dboule). The body includes an outer wall extending to an inner wall to define an upper lip. The outer wall has an outer circumference defining an outer wall diameter (ODwall), and the inner wall has an inner circumference defining an inner wall diameter (IDwall). The annular gasket is disposed on the upper lip and includes an outer gasket edge defining an outer circumference and an inner gasket edge defining an inner circumference. The outer circumference defines an outer gasket diameter (ODwash), and the inner circumference defines an inner gasket diameter (IDwash). An optimized ratio of the inner gasket diameter (IDwash) relative to the inner wall diameter (IDwall) is based on the ingot diameter (Dboule), the inner wall diameter (IDwall), and a target ratio parameter "Z".
[0004] According to another non-limiting embodiment, a method of assembling a crucible assembly is provided. The method includes forming a crucible comprising a body defining an interior volume configured to grow an ingot having an ingot diameter (Dboule). The body includes an outer wall extending to an inner wall to define an upper lip, the outer wall having an outer circumference defining an outer wall diameter (ODwall), and the inner wall having an inner circumference defining an inner wall diameter (IDwall). The method also includes forming an annular gasket configured to be disposed on the upper lip. The gasket includes an outer gasket edge defining an outer circumference and an inner gasket edge defining an inner circumference. The outer circumference defines an outer gasket diameter (ODwash), and the inner circumference defines an inner gasket diameter (IDwash). The method also includes determining an optimized ratio of the inner gasket diameter (IDwash) to the inner wall diameter (IDwall) based on the ingot diameter (Dboule), the inner wall diameter (IDwall), and a target ratio parameter "Z." BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims and accompanying drawings, in which:
[0006] Figure 1 is a perspective view of a crucible assembly according to a non-limiting embodiment of the present disclosure, the crucible assembly including a ratio of a gasket size to a crucible size and an ingot size;
[0007] Figure 2A According to a non-limiting embodiment of the present disclosure Figure 1 A perspective view of the crucible shown in ;
[0008] Figure 2B According to a non-limiting embodiment of the present disclosure Figure 2A A top view of the crucible shown in FIG;
[0009] Figure 3A According to a non-limiting embodiment of the present disclosure Figure 1 a perspective view of the gasket shown;
[0010] Figure 3B According to a non-limiting embodiment of the present disclosure Figure 3A A top view of the gasket shown in ;
[0011] Figure 4A According to a non-limiting embodiment of the present disclosure Figure 1 a perspective view of a crucible-grown ingot shown in FIG; and
[0012] Figure 4B According to a non-limiting embodiment of the present disclosure Figure 4A A top view of the ingot is shown in FIG. DETAILED DESCRIPTION
[0013] By referring to the following detailed description of the preferred embodiments of the present invention and the examples included therein, the present invention can be more easily understood. Regardless of whether it is clearly stated, all numerical values herein are assumed to be modified by the term "about". The term "about" generally refers to a numerical range that one skilled in the art would consider to be comparable (i.e., having the same function or result) to the value. In many cases, the term "about" may include a numerical value that is rounded to the nearest significant figure.
[0014] In producing an ingot, induction heating is used in a crucible to heat a powder of a raw material such as cerium-doped lutetium oxyorthosilicate Lu2SiO5:Ce (LSO), cerium-doped lutetium yttrium orthosilicate Lu 1.8 Y 0.2 SiO5:Ce(LYSO), Gadolinium aluminum gallium garnet Gd3Al2Ga3O 12(GAGG), etc. A gasket (also called a lid) is often placed on the crucible to prevent heat loss at the upper portion of the crucible, thereby allowing one to control the thermal gradient across the crystal-melt interface and facilitate the production of single crystal ingots in a portion of the crucible with minimal temperature fluctuations.
[0015] The dimensions of the crucible, washer, and / or ingot can affect the growth process and the quality of the produced ingot. For example, when the washer inner diameter (IDwall) is within 15 mm, preferably within 10 mm, preferably within 3 mm, and more preferably within 1 mm of the ingot diameter (Dboule), the ingot may contact the washer due to ingot precession (i.e., rocking during rotation), thereby damaging and deforming the ingot. In other cases, when the washer inner diameter is within 15 mm of the crucible inner diameter, thermal control in the region above the melt in the crucible is lost. As a result, the formation of the ingot may be slowed, hindered, or cause uneven crystal growth. However, conventional crucible assemblies do not take into account the dimensions of the crucible, washer, and ingot relative to each other. In addition, the presence of the washer can also affect later stages of the growth process, such as controlling radiative heat transfer, during which the crystal is sensitive to thermal stresses that can cause crystal fracture. Therefore, these conventional crucible assemblies fail to maintain and optimize the composition and structure of the ingot grown in the crucible.
[0016] Various non-limiting embodiments described herein address the deficiencies of conventional crucible assemblies described above by providing a crucible assembly having a targeted ratio of gasket size to crucible size and ingot size for scintillator manufacturing. The targeted ratio of gasket size to crucible size and ingot size suppresses heat loss and promotes uniformity of crystal structure and composition within the crystal structure while also avoiding damage and deformation of the ingot caused by ingot precession. Using a targeted ratio of gasket size to crucible size and ingot size to maintain steady-state temperature conditions in the crucible can further improve the retention and fidelity of the composition and structure of the single crystal ingot.
[0017] Now refer to Figure 1, a crucible assembly 20 (also referred to as a "production apparatus") is shown according to a non-limiting embodiment. The crucible assembly 20 includes a crucible 22 and a gasket 30 (sometimes referred to as a lid). The crucible 22 includes an interior volume 25 configured to accommodate a melt 26, and the gasket 30 is configured to cover the crucible 22. According to a non-limiting embodiment, the gasket 30 has a generally annular planar shape defining an opening 31. The opening 31 provides access to the crucible interior volume 25. Thus, a rotatable and retractable seed rod 42 included in a crystal pulling station (not shown) can be positioned to pass through the opening 31 and into the crucible 22. The end of the retractable seed rod 42 has a seed crystal (not shown) coupled thereto, the seed crystal being configured to contact the melt 26 while rotating and pulling the melt 26 upward to form an ingot 50 and pulling the ingot through the opening 31.
[0018] Steering Figure 2A and 2B , according to a non-limiting embodiment, a crucible 22 is shown included in the crucible assembly 20. The crucible 22 can be formed from various alloy materials, including but not limited to iridium alloys and molybdenum alloys. The crucible 22 has a body defined by an outer wall 23 and an inner wall 24. The distance between the outer wall 23 and the inner wall 24 defines the crucible thickness (Wwall). The crucible thickness (Wwall) ranges from, for example, approximately 10 microns to approximately 9525 microns (e.g., approximately 3 / 8 inch or 0.375 inch). According to a non-limiting embodiment, the outer wall 23 has an outer circumference defining an outer diameter (ODwall), and the inner wall 24 has an inner circumference defining an inner diameter (IDwall). The outer diameter (ODwall) can range from, for example, approximately 5.6 inches (approximately 142 mm) to approximately 30 inches (approximately 765 mm). The inner diameter (IDwall) can range from, for example, approximately 4.6 inches (approximately 140 mm) to approximately 29 inches (approximately 735 mm).
[0019] The outer wall 23 and the inner wall 24 extend from the bottom 27 to the upper lip 28, thereby forming a seamless curve that defines the interior volume 25. The distance between the bottom 27 and the upper lip 28 defines the crucible height (Hc). The crucible height (Hc) can be in the range of, for example, about 1.0 inches (about 25.5 mm) to about 30.0 inches (about 765 mm). Although the crucible 22 is shown as having a hemispherical shape, it should be understood that other shapes for holding the melt 26 and growing the ingot 50 (see FIG. 1 ) may be used without departing from the scope of the present invention. Figure 4A ) in any suitable shape.
[0020] Reference Figure 3A and 3B, according to a non-limiting embodiment, a gasket 30 is shown included in the crucible assembly 20. The gasket 30 and the crucible assembly 20 can be made of various alloy materials, including but not limited to iridium alloys and molybdenum alloys, tungsten, and composite materials with metal liners. According to a non-limiting embodiment, the gasket 30 has an annular gasket body 32 that extends circumferentially around a central axis to define an opening 31. The gasket 30 includes an outer gasket edge 34 that defines an outer circumference and an inner gasket edge 36 that defines an inner circumference. The distance between the outer gasket edge 34 and the inner gasket edge 36 defines a gasket width (Wwash), which in turn defines the size of the opening 31. The gasket width (Wwash) can be, for example, in a range from about 0.040 inches (1.016 mm) to about 6.0 inches (155 mm).
[0021] The outer circumference of the outer gasket edge 34 defines an outer gasket diameter (ODwash), and the inner circumference of the inner gasket edge 36 defines an inner gasket diameter (IDwash). The outer gasket diameter (ODwash) can be, for example, in the range of about 30 inches (about 765 mm) to about 31 inches (about 790 mm). The inner gasket diameter (IDwash) can be, for example, in the range of about 4.6 inches (about 117 mm) to about 30 inches (about 765 mm).
[0022] The gasket body 32 also includes a gasket bottom surface 38 and an opposing gasket top surface 40. The distance extending from the gasket bottom surface 38 to the gasket top surface 40 defines the gasket thickness (Twash). The gasket thickness (Twash) can be, for example, in the range of about 10 microns to about 9525 microns (e.g., about 3 / 8 inch or 0.375 inches). Although the gasket 30 is shown as having an annular shape, it should be understood that any suitable shape for suppressing heat loss from the crucible 22 can be used without departing from the scope of the present invention.
[0023] Go to Figure 4A and 4B , according to a non-limiting embodiment, an ingot 50 is shown grown from the crucible assembly 22. The ingot 50 may be formed from a variety of scintillator materials including, but not limited to, cerium-doped lutetium oxyorthosilicate Lu2SiO5:Ce (LSO), cerium-doped lutetium yttrium orthosilicate Lu2SiO5:Ce (LSO), and cerium-doped lutetium yttrium orthosilicate Lu2SiO5:Ce (LSO). (2-x) Y x SiO5:Ce(LYSO), cerium-doped lutetium gadolinium orthosilicate Lu (2-x) Gd x SiO5:Ce(LGSO), where x is 0.05 to 0.3, and Gd2SiO5:Ce(GSO), Y2SiO5:Ce(YSO), gadolinium aluminum gallium garnet co-doped with Ce and or Pr, such as Gd3Al2Ga3O 12Ingot 50 extends radially from a center point to an ingot outer surface 54 to define a cylindrical ingot body 52 having an ingot diameter (Dboule), which may range, for example, from about 1 inch (about 25.5 mm) to about 29 inches (about 735 mm). Ingot body 52 extends from a lower ingot surface 56 to an opposite upper ingot surface 58 to define an ingot height.
[0024] According to a non-limiting embodiment, the crucible assembly 20 includes a ratio of the size of the gasket 30 to the size of the crucible 22 and the size of the ingot 50 grown in the crucible 22. The ratio described according to one or more non-limiting embodiments of the present disclosure suppresses heat loss from the crucible 22 and maintains a stable target temperature within the crucible 22 during ingot production. In this way, the composition and structure of the ingot 50 formed in the crucible 22 can be maintained and maintained with fidelity.
[0025] According to a non-limiting embodiment, an optimized ratio of the inner diameter of the washer (IDwash) relative to the inner diameter of the crucible (IDwall) can be determined based on the ingot diameter (Dboule), the inner diameter of the crucible (IDwall), and a target ratio parameter "Z". For example, when the ingot diameter (Dboule) is "x" (e.g., x mm) and the inner diameter of the crucible (IDwall) is "y" (e.g., y mm), the optimized ratio of the inner diameter of the washer (IDwash) relative to the inner diameter of the crucible (IDwall) is defined as:
[0026] x+Z mm to yZ mm. [Equation 1]
[0027] According to a non-limiting embodiment, the target ratio parameter "Z" is set to 1 to 15 mm, preferably 3 to 15 mm, so that the optimized ratio of the inner diameter of the washer (IDwash) relative to the inner diameter of the crucible (IDwall) is defined as:
[0028] x+(1 to 15) mm to y-(1 to 15) mm. [Equation 2]
[0029] In other words, the inner wall diameter (IDwall) is always greater than the ingot diameter (Dboule). Moreover, the difference between the inner wall diameter (IDwall) and the target ratio parameter "Z" is always greater than the sum of the ingot diameter (Dboule) and the ratio parameter "Z". That is, in the above example, the inner diameter of the washer (IDwash) is x+(1 to 15) mm, and the inner diameter of the crucible (IDwall) is y-(1 to 15) mm, where y is always greater than x, and where y-(1 to 15) mm is always greater than x+(1 to 15) mm. In one embodiment, in the above example, the inner diameter of the washer (IDwash) is x+(3 to 15) mm, and the inner diameter of the crucible (IDwall) is y-(3 to 15) mm, where y is always greater than x, and where y-(3 to 15) mm is always greater than x+(3 to 15) mm.
[0030] In the above non-limiting embodiment, setting the target ratio parameter "Z" to as high as 5 mm provides an optimized ratio of the inner diameter of the washer (IDwash) relative to the inner diameter of the crucible (IDwall), which suppresses heat loss from the crucible 22 and promotes uniformity in the structure and composition of the produced ingot 50, while also avoiding damage and deformation of the ingot 50 that may be caused by ingot precession. Furthermore, in this example, the optimized ratio of the inner diameter of the washer (IDwash) relative to the inner diameter of the crucible (IDwall) (e.g., setting the target ratio parameter to between 1 and 15 mm) maintains steady-state temperature conditions in the crucible 22, which in turn achieves preservation and fidelity of the composition and structure of the ingot 50 during the crystal growth process.
[0031] As described herein, various non-limiting embodiments of the present disclosure provide a crucible assembly having a targeted ratio of gasket size to crucible size and ingot size for scintillator manufacturing. This targeted ratio of gasket size to crucible size and ingot size suppresses heat loss, promoting uniformity in the crystal structure and composition within the crystal structure, while also avoiding damage and deformation of the ingot caused by ingot precession. By maintaining steady-state temperature conditions within the crucible, the retention and fidelity of the composition and structure of the single crystal ingot can be further improved.
[0032] Although the present invention has been described in considerable detail with reference to certain preferred forms thereof, other forms are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred forms contained herein.
[0033] The reader's attention is directed to all papers and documents filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
[0034] Unless expressly stated otherwise, all features disclosed in this specification (including any accompanying claims, abstracts, and drawings) may be replaced by alternative features serving the same, equivalent, or similar purpose. Therefore, unless expressly stated otherwise, each feature disclosed is only one example of a generic series of equivalent or similar features.
[0035] Any element in a claim that does not explicitly recite “means for performing a specified function” or “steps for performing a specified function” should not be construed as constituting a “means” or “step” clause as provided in the sixth paragraph of 35 U.S.C. § 112. In particular, the use of “step” in the claims herein is not intended to invoke the provisions of the sixth paragraph of 35 U.S.C. § 112.
Claims
1. A crucible assembly comprising: a crucible comprising a body defining an interior volume configured to grow an ingot having an ingot diameter (Dboule), the body comprising an outer wall extending to an inner wall to define an upper lip, the outer wall having an outer circumference defining an outer wall diameter (ODwall), and the inner wall having an inner circumference defining an inner wall diameter (IDwall); an annular gasket disposed on the upper lip, the gasket including an outer gasket edge defining an outer circumference and an inner gasket edge defining an inner circumference, the outer circumference defining an outer gasket diameter (ODwash), and the inner circumference defining an inner gasket diameter (IDwash), The optimized ratio of the inner washer diameter (IDwash) to the inner wall diameter (IDwall) is based on the ingot diameter (Dboule), the inner wall diameter (IDwall), and a target ratio parameter "Z".
2. The crucible assembly of claim 1, wherein: The inner wall diameter (IDwall) is always larger than the ingot diameter (Dboule).
3. The crucible assembly of claim 2, wherein: The difference between the inner wall diameter (IDwall) and the target ratio parameter "Z" is always greater than the sum of the ingot diameter (Dboule) and the target ratio parameter "Z".
4. The crucible assembly of claim 3, wherein: The inner gasket diameter (IDwash) is in a range from equal to or greater than 4.6 inches (about 117 mm) to equal to or less than 30 inches (about 765 mm), and wherein the inner wall diameter (IDwall) is in a range from equal to or greater than 4.6 inches (about 117 mm) to equal to or less than 29 inches (about 735 mm).
5. The crucible assembly of claim 4, wherein: The target ratio parameter "Z" is 1 to 15 millimeters (mm).
6. The crucible assembly of claim 5, wherein: The ingot diameter (Dboule) is equal to or greater than about 1 inch (about 25.5 mm) to equal to or less than about 29.0 inches (about 735 mm).
7. The crucible assembly of claim 6, wherein: The inner and outer walls extend from the bottom to the upper lip to define a height (Hc) of the crucible.
8. The crucible assembly of claim 7, wherein: The crucible height (Hc) ranges from equal to or greater than about 1 inch (about 25.5 mm) to equal to or less than about 30.0 inches (about 765 mm).
9. The crucible assembly of claim 1, wherein: One or both of the crucible and the gasket include an iridium alloy or a molybdenum alloy.
10. A method of assembling a crucible assembly, the method comprising: forming a crucible comprising a body defining an interior volume configured to grow an ingot having an ingot diameter (Dboule), the body comprising an outer wall extending to an inner wall to define an upper lip, the outer wall having an outer circumference defining an outer wall diameter (ODwall), and the inner wall having an inner circumference defining an inner wall diameter (IDwall); forming an annular gasket configured to be disposed on the upper lip, the gasket including an outer gasket edge defining an outer circumference and an inner gasket edge defining an inner circumference, the outer circumference defining an outer gasket diameter (ODwash), and the inner circumference defining an inner gasket diameter (IDwash); and An optimized ratio of the inner washer diameter (IDwash) to the inner wall diameter (IDwall) is determined based on the ingot diameter (Dboule), the inner wall diameter (IDwall), and a target ratio parameter "Z." 11. The method according to claim 10, wherein: Forming the crucible includes forming the inner wall diameter (IDwall) such that it is always larger than the ingot diameter (Dboule).
12. The method of claim 11, wherein: Forming the crucible includes establishing a difference between the inner wall diameter (IDwall) and the target ratio parameter "Z", the difference always being greater than the sum of the ingot diameter (Dboule) and the target ratio parameter "Z".
13. The method of claim 12, wherein: The inner gasket diameter (IDwash) is in a range from equal to or greater than 4.6 inches (about 117 mm) to equal to or less than 30 inches (about 765 mm), and wherein the inner wall diameter (IDwall) is in a range from equal to or greater than 5.5 inches (about 140 mm) to equal to or less than 29 inches (about 735 mm).
14. The method of claim 13, wherein: The target ratio parameter "Z" is 1 to 15 millimeters (mm).
15. The method of claim 14, wherein: The ingot diameter (Dboule) ranges from equal to or greater than about 1 inch (about 25.5 mm) to equal to or less than about 29.0 inches (about 735 mm).
16. The method of claim 15, wherein: The inner and outer walls extend from the bottom to the upper lip to define a height (Hc) of the crucible.
17. The method of claim 16, wherein: The crucible has a height (Hc) ranging from equal to or greater than about 1 inch (about 25.5 mm) to equal to or less than about 30.0 inches (about 765 mm).
18. The method of claim 10, wherein: One or both of the crucible and the gasket include an iridium alloy or a molybdenum alloy.