CN114839664A - Submillimeter-level high-resolution scintillation crystal array and preparation method and application thereof - Google Patents

Abstract

The invention relates to a submillimeter-level high-resolution scintillation crystal array and a preparation method and application thereof. The submillimeter-level high-resolution scintillation crystal array comprises: the array comprises a plurality of scintillation crystal pixel crystal columns with the diameter or the side length of 0.1-1 mm, a high-reflection dielectric layer and a light-blocking dielectric layer which are used for separating each scintillation crystal pixel crystal column, and a mould which is used for arranging and fixing the scintillation crystal pixel crystal columns to form the array or a bonding matrix which is used for arranging and fixing the scintillation crystal pixel crystal columns to form the array and is distributed in the array interval.

Description

A sub-millimeter high-resolution scintillation crystal array and its preparation method and application

technical field

The invention relates to a submillimeter-level high-resolution scintillation crystal array, a preparation method and application thereof, and belongs to the technical field of radiation detection high-resolution imaging.

Background technique

Scintillation crystal is one of the basic materials with great military and technological significance in modern materials. During the nearly 70 years of development of scintillation crystals, a series of new scintillation crystals with excellent performance have been successively developed. The oxide scintillation crystal family has successively been born such as BGO, CWO, PWO, LYSO, La-GPS:Ce, GAGG, ZnO :Ga and other scintillation crystals with excellent performance, and the halide scintillation crystal family has successively born such as NaI:Tl, CsI:Tl, BaF ₂ :Y, LaBr ₃ :Ce, SrI ₂ :Eu, CsBa2I ₅ :Eu and other excellent scintillation crystals Scintillation crystals. As an important radiation detection material, it can be widely used in high-energy physics, space physics, nuclear medicine imaging, security inspection, oil well exploration, online mineral sorting and other fields, and its global market share is as high as billions of yuan every year. Moreover, it is the current and future development trend to achieve high spatial resolution, high sensitivity, fast response, stability and durability, and multiple online radiation detection imaging technologies. The preparation of submillimeter-scale high-resolution scintillation crystal arrays by pixelating bulk scintillation crystals is an important technology. It is an important way to realize the above application requirements.

However, the existing technology for preparing scintillation crystal arrays is to coordinate and repeat multiple processes of cutting, grinding, polishing, and coating the bulk crystals to finally assemble the scintillation crystal array. It consumes huge manpower and material resources and the yield rate is very low. Pixelation of scintillation crystals by machining to the sub-millimeter scale comes with various complications, especially for hard, brittle, and hygroscopic materials. For example, LYSO, a hard and brittle scintillation crystal of interest to the medical imaging community, is known to crack under thermal and mechanical stress; the low material utilization of pixel pillars with large aspect ratios will result in a rapid drop in yield and significant cost. Increase. Also, it is very challenging to process and assemble discrete crystals smaller than 1 mm in size, so submillimeter-scale crystal arrays are often very expensive. The quality of these arrays depends heavily on the skill of the vendor and does not always meet the requirements. After pixelation, a reflective material needs to be inserted between the scintillator columns to separate the individual crystals in the array. If its thickness is fixed (assumed to be 0.1mm), the smaller the size of the scintillation crystal pixel column, the better the filling factor of the crystals in the array. Smaller, the smaller the sensitivity of the system.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a sub-millimeter high-resolution scintillation crystal array and a preparation method and application thereof.

In one aspect, the present invention provides a sub-millimeter high-resolution scintillation crystal array, comprising: an array composed of a plurality of scintillation crystal pixel columns with a diameter or side length of 0.1-1 mm, which are used to separate each scintillation crystal pixel crystal. High-reflection medium layer and light-blocking medium layer of pillars, and a mold for arranging and fixing scintillation crystal pixel pillars to form an array or a bonding matrix for arranging and fixing scintillation crystal pixel pillars to form an array and distributed inside the array space .

In the present disclosure, the scintillation crystal array of sub-millimeter scale (0.1-1 mm) means that it has extremely high pixels in the imaging field, which greatly improves the spatial resolution of the scintillation detector.

Preferably, the composition of the scintillation crystal pixel crystal column includes: rare earth sesquioxide-based scintillation crystal RE ₂ O ₃ , silicate-based scintillation crystal, aluminate-based scintillation crystal, and aluminum gallate-based scintillation crystal RE ₃ Al _5x Ga _5-5x O ₁₂ , bismuth germanate-based scintillation crystal Bi ₄ Ge ₃ O ₁₂ , tungstate-based scintillation crystal, alkaline earth metal fluoride-based scintillation crystal, rare earth bromide-based scintillation crystal REBr ₃ , alkali metal iodine At least one of compound-based scintillation crystal and alkaline earth metal iodide-based scintillation crystal; wherein, RE is rare earth ion including lanthanum (La), cerium (Ce), praseodymium (Pr), europium (Eu), gadolinium (Gd), ytterbium At least one of (Yb), lutetium (Lu), scandium (Sc), and yttrium (Y).

Preferably, the silicate-based scintillation crystal is at least one of RE ₂ SiO ₅ and RE ₂ Si ₂ O ₇ ;

The aluminate-based scintillation crystal is at least one of RE ₃ Al ₅ O ₁₂ and REAlO ₃ ;

The tungstate-based scintillation crystal is at least one of PbWO _{4 , CdWO 4 ,} ZnWO ₄ , and CaWO ₄ ;

The alkaline earth metal fluoride-based scintillation crystal is at least one of CaF ₂ and BaF ₂ ;

The alkali metal iodide-based scintillation crystal is at least one of NaI and CsI;

The alkaline earth metal iodide-based scintillation crystal is SrI ₂ .

Preferably, when RE in the rare earth sesquioxide-based scintillation crystal RE ₂ O ₃ is selected from at least one of lanthanum (La), gadolinium (Gd), lutetium (Lu), scandium (Sc), yttrium (Y) and When at least one of cerium (Ce), praseodymium (Pr), and europium (Eu), the total content of at least one of cerium (Ce), praseodymium (Pr), and europium (Eu) is 0.01 to 5 at.%;

When the silicate-based scintillation crystal, aluminate-based scintillation crystal, alumino-gallate-based scintillation crystal, rare earth bromide (REBr ₃ )-based scintillation crystal, RE is selected from lanthanum (La), gadolinium (Gd), lutetium (Lu) ), scandium (Sc), yttrium (Y) and at least one of cerium (Ce), praseodymium (Pr), europium (Eu), and ytterbium (Yb), the cerium (Ce), praseodymium ( The total content of at least one of Pr), europium (Eu), and ytterbium (Yb) is 0.01 to 5 at.%;

The alkali metal iodide-based scintillation crystal and the alkaline earth metal iodide-based scintillation crystal are doped with at least one of thallium (Tl) and europium (Eu). The total content is 0～5at.%.

Preferably, the cross-sectional shape of the scintillation crystal pixel column is a circle, a square or a rectangle, preferably a square.

Preferably, the composition of the high-reflection medium layer is selected from materials with a reflectivity of ≥95% in the visible light region, including at least one of metals, barium sulfate, titanium dioxide, photonic crystals, Teflon, and ESR reflective films. It is at least one of magnesium, aluminum, gallium, indium, tin, zinc, silver, platinum, ruthenium, osmium, iridium, and rhenium; the thickness of the high-reflection medium layer is 0.1-500 microns;

The light-shielding medium layer is a high atomic coefficient light-absorbing material, at least one selected from lead, tungsten, and tantalum; the light-shielding medium layer has a thickness of 0-500 microns.

Preferably, the material of the mold is selected from at least one of tungsten, lead, tantalum, ruthenium, osmium, iridium, rhenium, Teflon, and polyvinyl chloride.

Preferably, the bonding matrix is at least selected from epoxy resin, silicone resin, polyacrylic resin, polyethylene glycol resin, polyvinyl butyral resin, polyvinyl alcohol resin, and polyimide resin. One; the thickness of the bonding matrix is 1-200 microns.

In a second aspect, the present invention provides a method for preparing a sub-millimeter high-resolution scintillation crystal array, comprising:

(1) Using the single crystal growth technology to grow an elongated scintillation crystal fiber with a size of 0.1 to 1 mm in one step as a scintillation crystal pixel column;

(2) preparing a high-reflection medium layer and a light-shielding medium layer on the surface of the scintillation crystal pixel crystal column by in-situ growth or secondary processing;

(3) The scintillation crystal pixel crystal columns with the high reflection medium layer and the light-shielding medium layer are bundled and bonded by a bonding matrix or fixedly arranged by a mold to form an array, that is, a submillimeter high-resolution scintillation crystal array is obtained.

In a third aspect, the present invention provides a method for preparing a sub-millimeter high-resolution scintillation crystal array, comprising:

(1) Using the structure of a submillimeter high-resolution scintillation crystal array to prepare a mold with a submillimeter aperture array structure skeleton, the mold with a submillimeter aperture array structure skeleton is composed of at least one of the high reflection medium layer and the light blocking medium layer. One, and the melting point of the mold with the sub-millimeter aperture array structure skeleton > the melting point of the scintillation crystal pixel crystal column;

(2) Immerse the mold with the submillimeter aperture array structure skeleton in the melt of the scintillation crystal pixel crystal column, and grow the submillimeter high-resolution scintillation crystal array with a high reflection medium or a light-shielding medium by a one-step method.

In a fourth aspect, the present invention provides an application of a sub-millimeter high-resolution scintillation crystal array in X-ray flash photography and medical imaging.

Beneficial effects:

1. The sub-millimeter high-resolution scintillation crystal array prepared by the present invention greatly improves the position (spatial) resolution of the scintillation detector, and will show broad application prospects in the fields of radiation detection and high-resolution imaging;

2. Using a specific single crystal growth technology to prepare a sub-millimeter-level scintillation crystal fiber with a smooth surface as a pixel crystal column in one step, it avoids the need to coordinate and repeat the multiple processes of cutting, grinding, polishing, coating, and assembling the bulk crystal. The current situation that huge manpower and material resources are needed and the yield rate is very low;

3. The extremely simple and quick process steps are conducive to the automatic production of sub-millimeter high-resolution scintillation crystal arrays. There is basically no cutting and grinding loss in the whole process, which greatly improves the utilization rate of scintillation crystal materials.

Description of drawings

Figure 1 is an aluminate (RE ₃ Al ₅ O ₁₂ , RE is a mixture of Y and Lu, Y:Lu=0.9:0.1)-based columnar scintillation crystal fiber prepared by a laser heating pedestal method in Example 3;

Figure 2 shows the assembled silicate (RE ₂ SiO ₅ , RE is a mixture of Lu, Gd and Ce, Lu:Gd:Ce=0.949:0.05:0.001)-based columnar scintillation crystal fiber prepared by the micro-pull-down method in Example 9 Submillimeter high-resolution scintillation crystal array;

Figure 3 shows the assembled silicate (RE ₂ SiO ₅ , RE is a mixture of Lu, Gd and Ce, Lu:Gd:Ce=0.949:0.05:0.001)-based columnar scintillation crystal fiber prepared by the micro-pull-down method in Example 9 Submillimeter-scale high-resolution scintillation crystal arrays.

Detailed ways

The present invention is further described below through the following embodiments, and it should be understood that the following embodiments are only used to illustrate the present invention, but not to limit the present invention.

In the present invention, the sub-millimeter high-resolution scintillation crystal array includes: an array composed of a plurality of scintillation crystal pixel columns with a diameter/side length of 0.1-1 mm, a high-reflection medium used to separate each scintillation crystal pixel column layer and light-blocking medium layer, and a mold or bonding matrix for arranging and fixing the scintillation crystal pixel pillars to form an array. It is prepared by conventional mechanical processing methods. The limitation of this method is that the crystal material loss is large, the processing cycle is long, and the cost is much higher than that of the method of directly preparing 0.1-1 mm scintillation crystals in the present invention.

The following exemplarily illustrates the preparation method of the sub-millimeter high-resolution scintillation crystal array.

method one:

The scintillation crystal fiber with the size of the scintillation crystal pixel crystal column of 0.1-1 mm is grown in one step by using a specific single crystal growth technology. Wherein, the specific single crystal growth technique includes at least one of a laser heating pedestal method, a micro-draw down method, a guided mode method, and a fusion wire drawing method. Preferably, surface polishing is performed on the grown scintillation crystal fiber.

A high-reflection medium layer (reflectivity≥99%) is prepared on the surface of the crystal fiber by in-situ growth or reprocessing, and then a light-shielding medium layer is prepared. Specifically, the in-situ growth of the high-reflection medium layer, that is, using the temperature gradient existing during single crystal growth, the reflective medium is melted in a high-temperature region and solidified in a lower-temperature region to form a reflective medium layer, characterized in that the in-situ growth includes: At least one of metal, barium sulfate, and Teflon medium, with a thickness of 0.1-500 microns. The method of reprocessing (secondary processing) is to use magnetron sputtering method, vacuum evaporation method, chemical vapor deposition method, electroplating method, solution dipping method, coating method, spraying method and glue method on the surface of scintillation crystal fiber at least. One, the high reflectivity medium is prepared on the surface of the scintillation crystal fiber, with a thickness of 0.1-500 microns. The light-shielding medium layer adopts at least one of magnetron sputtering method, vacuum evaporation method, chemical vapor deposition method, electroplating method, solution dipping method, coating method, spraying method and gluing method on the surface of the high reflectivity medium layer, The high atomic coefficient light-absorbing material is prepared on the outermost layer of the scintillation crystal fiber to block the crosstalk of scintillation light and rays between the pixel crystal columns, with a thickness of 0-500 microns; preferably, the high-reflection medium adopts a solution dipping method, coating Method, spray method and glue method need to be used in conjunction with bonding matrix.

The scintillation crystal fiber with the dielectric layer is bundled and bonded by the bonding matrix or the mold is fixedly arranged to form an array, that is, a submillimeter-level high-resolution scintillation crystal array is obtained. Among them, the crystal fibers are arranged in an array by means of bundling and bonding or mold fixing, and it is characterized in that, the bundling method needs to limit the clamp; the method of fixing the mold is to use the CNC method or the laser engraving method to make the scintillation with the dielectric layer. A micro-hole array mold with similar crystal fibers in size is inserted, and the scintillation crystal fiber with a dielectric layer is inserted into the micro-holes of the mold and fixed to obtain a sub-millimeter high-resolution scintillation crystal array. The mold used in the present invention does not need to be separated, and finally becomes a part of the scintillation crystal array, which can be used as a light-shielding and anti-crosstalk material or a high-reflection material.

Method 2: Sub-millimeter high-resolution scintillation crystal arrays with high-reflection medium or light-shielding medium are grown in one step by dipping a mold with a specific structure into the melt. Wherein, the mold with a specific structure is a skeleton with a sub-millimeter aperture array structure to realize the size limit during crystal growth, and is selected from at least one of high-reflection medium or light-shielding medium, and the melting point is higher than that of the prepared pixel crystal column. melting point. The main purpose of this technology is to fill the melt into a mold with a specific structure and slowly solidify to form a sub-millimeter high-resolution scintillation crystal array. The filling and solidification methods of the melt include immersion solidification, inflow solidification, and pull solidification. The key parameters are: Precisely control the cooling rate (less than 10°C/h in the initial stage of solidification) to ensure the formation of high-quality scintillation crystal pixel columns, preferably immersion solidification and pulling solidification. The mold used in the present invention does not need to be separated, and finally becomes a part of the scintillation crystal array, which can be used as a light-shielding and anti-crosstalk material or a high-reflection material.

In the present invention, it is easy to realize the automated production line of the scintillation crystal array: the material is solidified from the melt into a crystal of the target size, eliminating a large number of manual processing steps; the subsequent process includes preparing a reflective layer and a scintillation crystal on the surface of the crystal. The arrangement of the pixel crystal columns is significantly better than the current process method, which is the key technology for batch preparation of sub-millimeter high-resolution scintillation crystal arrays. The preparation cost of the present invention is significantly lower than the current conventional process and the production efficiency is greatly improved. The extremely simple process steps can be used to prepare a scintillation crystal array that currently requires at least four processes to be coordinated in one step.

The following further examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention, and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present invention belong to the present invention. scope of protection. The specific process parameters and the like in the following examples are only an example of a suitable range, that is, those skilled in the art can make selections within the suitable range through the description herein, and are not intended to be limited to the specific numerical values exemplified below.

Example 1

A silicate (RE ₂ SiO ₅ , RE is a mixture of Lu, Y and Ce, Lu:Y:Ce=0.899:0.1:0.001)-based columnar scintillation crystal fiber is prepared by a laser heating pedestal method. The preparation process includes: ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , and SiO ₂ are prepared according to the chemical formula ratio, mixed uniformly, and then made into a material column with a diameter of 0.5-2mm and compacted in a 200Mpa isostatic press. Put it in a muffle furnace at 1600°C for 10h, then take out the material column and put it on the sample stage of the laser heating base, irradiate the focused laser beam to one end of the material column to melt it, and then use a seed crystal with a diameter of about 1mm to complete it. For seeding and seeding, the diameter of the obtained scintillation crystal optical fiber is controlled by adjusting the pulling speed to be in the range of 0.1-0.5 mm, and the length is preferably 50-500 mm. In the subsequent steps, the average diameter of the obtained columnar scintillation crystal fiber is 0.3 mm and the length is 100 mm as an example. The obtained columnar scintillation crystal fiber is prepared into a sub-millimeter high-resolution scintillation crystal array. Silver coating, then electroplating is used to deposit a layer of lead with a thickness of 20 μm on the outside of the silver layer as a light shielding medium, and a 20 μm thick epoxy resin is coated on the periphery of the light shielding medium as a bonding matrix to bind the scintillation crystal fiber. After solidification, the crystal fiber is cut along the vertical direction of the crystal fiber by diamond wire cutting according to the predetermined thickness of the array, and the cut arrays are spliced to the same surface to obtain a sub-millimeter high-resolution scintillation crystal array.

Example 2

The columnar scintillation crystal fiber prepared in Example 1 was prepared into a sub-millimeter high-resolution scintillation crystal array: the surface of the scintillation crystal fiber was polished and directly inserted into tungsten dipped in polyvinyl butyral resin with a barium sulfate solid content of more than 60 wt%. It is fixed in the mold and allowed to cure, then it is cut and spliced to the desired array size. Alternatively, the columnar scintillation crystal fiber is pre-cut to the required array thickness size and then inserted into a tungsten mold that has met the target size to be fixed and cured to obtain a submillimeter-scale high-resolution scintillation crystal array.

Example 3

Aluminate (RE ₃ Al ₅ O ₁₂ , RE is a mixture of Y and Lu, Y:Lu=0.9:0.1)-based columnar scintillation crystal fiber is prepared by a laser heating pedestal method. The preparation process includes: Y ₂ O ₃ , Lu ₂ O ₃ and Al ₂ O ₃ are prepared according to the chemical formula ratio, mixed uniformly, and then made into a material column with a diameter of 0.5-2 mm and compacted in a 200 Mpa isostatic press. Put it in a muffle furnace at 1400°C for 10h, then take out the material column and put it on the sample stage of the laser heating base, irradiate the focused laser beam to one end of the material column to melt it, and then use a seed crystal with a diameter of about 1mm to complete For seeding and seeding, the diameter of the obtained scintillation crystal fiber is controlled by adjusting the pulling speed to be in the range of 0.1-1 mm, and the length is preferably 50-500 mm. In the subsequent steps, the average diameter of the obtained columnar scintillation crystal fiber is 0.1 mm and the length is 150 mm as an example. The obtained columnar scintillation crystal fiber is prepared into a sub-millimeter high-resolution scintillation crystal array, and the preparation method includes: polishing the surface of the scintillation crystal fiber and gluing a layer of ESR on the outer wall of the scintillation crystal fiber by using epoxy resin as a glue, and using epoxy resin as a glue on the outer wall of the scintillation medium. Coating 20μm thick epoxy resin as a bonding matrix to bundle and bond the scintillation crystal fiber into an array. After curing, the crystal fiber is cut along the vertical direction of the direction of the crystal fiber according to the predetermined thickness of the array by diamond wire cutting. The open arrays are spliced to the same surface to obtain a sub-millimeter high-resolution scintillation crystal array.

Example 4

Rare earth sesquioxide (RE ₂ O ₃ , RE is a mixture of Lu and Eu, Lu:Eu=0.95:0.05)-based columnar scintillation crystal fiber is prepared by a laser heating pedestal method. The preparation process includes: mixing Lu ₂ O ₃ , Eu ₂ O ₃ is prepared according to the chemical formula ratio, mixed uniformly, and then made into a material column with a diameter of 0.5-2 mm and compacted in a 200 Mpa isostatic press. Put it in a muffle furnace at 1600°C for 10h, then take out the material column and put it on the sample stage of the laser heating base, irradiate the focused laser beam to one end of the material column to melt it, and then use a seed crystal with a diameter of about 1mm to complete it. For seeding and seeding, the diameter of the obtained scintillation crystal fiber is controlled by adjusting the pulling speed to be in the range of 0.1-0.4 mm, and the length is preferably 50-500 mm. In the subsequent steps, the average diameter of the obtained columnar scintillation crystal fiber is 0.4 mm and the length is 50 mm as an example. The obtained columnar scintillation crystal fiber is prepared into a sub-millimeter high-resolution scintillation crystal array, and the preparation method includes: polishing the surface of the scintillation crystal fiber, wrapping the outer wall of the scintillation crystal fiber with polytetrafluoroethylene, inserting the scintillation crystal fiber into the scintillation crystal fiber with a solid content of more than 60wt% The epoxy resin is fixed in a tantalum mold and allowed to cure, then it is cut and spliced to the desired array size.

Example 5

The bismuth germanate (Bi ₄ Ge ₃ O ₁₂ )-based columnar scintillation crystal fiber is prepared by a laser heating pedestal method. The preparation process includes: preparing Bi ₂ O ₃ and GeO ₂ according to chemical formula ratios, mixing them uniformly, and then making them into The material column with a diameter of 0.5-2mm is compacted in a 200Mpa isostatic press. Put it in a muffle furnace at 800°C for 10h, then take out the material column and put it on the sample stage of the laser heating base, irradiate the focused laser beam to one end of the material column to melt it, and then use a seed crystal with a diameter of about 1mm to complete it. For seeding and seeding, the diameter of the obtained scintillation crystal fiber is controlled by adjusting the pulling speed to be in the range of 0.1-1 mm, and the length is preferably 50-500 mm. In the subsequent steps, the average diameter of the obtained columnar scintillation crystal fiber is 0.8 mm and the length is 200 mm as an example. The obtained columnar scintillation crystal fiber is prepared into a sub-millimeter high-resolution scintillation crystal array. Then insert it into a lead mold dipped in titanium dioxide polyimide resin to fix it and wait for it to be cured. After it is cured, the crystal fiber is cut along the vertical direction of the direction of the crystal fiber according to the predetermined thickness of the array by diamond wire cutting. The split arrays are spliced to the same plane to obtain sub-millimeter high-resolution scintillation crystal arrays.

Example 6

Alkaline earth metal fluoride (BaF ₂ )-based columnar scintillation crystal fiber is prepared by laser heating pedestal method. The preparation process includes: making BaF ₂ into a column with a diameter of 0.5-2 mm and compacting it in a 200Mpa isostatic press. . Then put the material column on the sample stage of the laser heating base, irradiate the focused laser beam to one end of the material column to melt it, and then complete the seeding and seeding with a BaF ₂ seed crystal with a diameter of about 1mm. By adjusting the pulling speed The diameter of the obtained scintillation crystal fiber is controlled to be in the range of 0.1-1 mm, and the length is preferably 50-500 mm. In the subsequent steps, the average diameter of the obtained columnar scintillation crystal fiber is 0.2 mm and the length is 200 mm as an example. Refer to Example 1 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 7

Aluminogallate (RE ₃ Al _5x Ga _(5-5x) O ₁₂ , RE is a mixture of Gd and Ce, Gd:Ce=0.995:0.005, x=0.4)-based columnar scintillation crystal fiber was prepared by micro-pull-down method. The process includes: preparing Gd ₂ O ₃ , CeO ₂ , Al ₂ O ₃ , Ga ₂ O ₃ according to the chemical formula ratio, mixing them evenly, then putting them into an iridium crucible with a diameter of 0.8 mm at the lower end, and then crystallizing the lower end of the crucible A zirconia boat is set in the area that the growth needs to pass through and a small hole slightly larger than 1 mm is left at the bottom, and the boat is filled with silver metal. The seed crystal with a diameter of about 1mm passes through the zirconia boat and the silver metal contained in it and is as close as possible to the small hole in the lower part of the iridium crucible and aligned. Subsequently, the material in the iridium crucible is heated by the induction coil to melt and complete the inoculation and seeding. By adjusting the position of the zirconia boat, the metal in it is melted and can be deposited on the outer wall of the crystal by the pull-down of the crystal. Adjustment applied to the induction coil The power above keeps the crystal quality linearly increasing during the growth process. The diameter of the obtained scintillation crystal fiber is 0.8 mm, the length is preferably 50-500 mm, and the thickness of the silver cladding is in the range of 0.1-1 mm. Refer to Example 2 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 8

Aluminate (RE ₃ Al ₅ O ₁₂ , RE is a mixture of Y and Pr, Y:Pr=0.999:0.001)-based columnar scintillation crystal fiber was prepared by micro-pull-down method. The preparation process includes: Y ₂ O ₃ , Pr ₆ O ₁₁ and Al ₂ O ₃ are prepared according to the chemical formula ratio, mixed evenly, and then put them into an iridium crucible with a number of (500 as an example) square holes with a side length of 0.5mm with a uniform interval at the lower end and heated by an induction coil The material in the crucible was melted, followed by seeding and seeding with seed crystals with a diameter close to the total diameter of the bottom surface of the crucible, and the linear growth of the crystal quality during the growth process was maintained by adjusting the power applied to the induction coil. The side length of the section is 0.5mm, and the length is preferably 50-500mm. The number of scintillation crystal fibers prepared depends on the number of openings at the lower end of the crucible, and the simultaneous growth of several or even thousands of fibers can be achieved. Refer to Example 1 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 9

A silicate (RE ₂ SiO ₅ , RE is a mixture of Lu, Gd and Ce, Lu:Gd:Ce=0.949:0.05:0.001)-based columnar scintillation crystal fiber is prepared by a micro-pull-down method. The preparation process includes: mixing Lu ₂ O _3. Gd ₂ O ₃ , CeO ₂ and SiO ₂ are prepared according to the chemical formula ratio, mixed evenly, then put them into an iridium crucible with a side length of 0.3 mm at the lower end and heated by an induction coil to melt them, and then use a diameter of about 0.5 mm to melt them. The seed crystal of about mm is inoculated and seeded, and the linear growth of crystal quality is maintained by adjusting the power applied to the induction coil. The cross-sectional side length of the obtained scintillation crystal fiber is 0.3 mm, and the length is preferably 50-500 mm. The obtained columnar scintillation crystal fiber is prepared into a sub-millimeter high-resolution scintillation crystal array. It is cured in an epoxy resin with a solid content of titanium dioxide above 60 wt%, and then it is cut and spliced into a desired array size.

Example 10

Alkali metal iodide (CsI: 0.05%Tl)-based columnar scintillation crystal fiber is prepared by micro-pull-down method. The preparation process includes: preparing CsI and TlI according to the chemical formula ratio, mixing them evenly, and then loading them into a 0.8mm diameter opening at the lower end. In the quartz crucible, a quartz boat is then set in the area where the crystal growth at the lower end of the crucible needs to pass, and a small hole slightly larger than 1 mm is left at the bottom, and the boat is filled with Teflon. Seed crystals with a diameter of about 1 mm pass through the quartz boat and the Teflon contained in it, as close as possible to the small hole in the lower part of the crucible and align. Subsequently, the material in the crucible was melted by resistance heating to complete inoculation and seeding. By adjusting the position of the quartz boat, the polytetrafluoroethylene in the crucible was melted and condensed on the outer wall of the crystal while the crystal was pulled down. The obtained scintillation crystal fiber had The diameter is 0.8mm, the length is preferably 50-500mm, and the thickness of the polytetrafluoroethylene cladding is in the range of 0.1-1mm. Refer to Example 4 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 11

A silicate (RE ₂ SiO ₅ , RE is a mixture of Lu, Y and Ce, Lu:Y:Ce=0.899:0.1:0.001)-based columnar scintillation crystal fiber is prepared by the guided mode method. The preparation process includes: mixing Lu ₂ O _3. Y ₂ O ₃ , CeO ₂ , SiO ₂ are prepared according to the chemical formula ratio, mixed evenly, then put into the iridium crucible and placed above the crucible with a plurality of (100 as an example) square holes with a side length of 0.9mm convex The raised iridium material mold is heated by an induction coil to melt the material in the iridium crucible, and the iridium mold is infiltrated into the melt, and then a seed crystal with a diameter equivalent to the mold section is used to align the mold to complete inoculation and seeding to obtain a cross-sectional edge. For 100 scintillation crystal fibers with a length of 0.9 mm, the length is preferably 50 to 500 mm. The number of scintillation crystal fibers prepared depends on the number of protruding holes in the mold, which can achieve simultaneous growth of several or even thousands of fibers. Refer to Example 5 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 12

Aluminate (RE ₃ Al ₅ O ₁₂ , RE is a mixture of Lu and Ce, Lu:Ce=0.995:0.005)-based columnar scintillation crystal fiber is prepared by melting drawing method, and the preparation process includes: Lu ₂ O ₃ , Al ₂ O ₃ and CeO ₂ are prepared according to chemical formula ratios, mixed uniformly, and then made into preforms with a diameter of 0.5-2 mm and compacted in a 200Mpa isostatic press. Put it in a muffle furnace at 1400°C for 10 hours, then take it out and bond it to the corundum ceramic rod with high temperature glue, insert the preform into the tungsten heating tube sleeve and heat up under the action of induction to melt the end of the preform, and then use a diameter of about Seed crystals of about 1 mm are inoculated and drawn, and the diameter of the obtained scintillation crystal fiber is controlled to be in the range of 0.1 to 1 mm by adjusting the pulling speed, and the length is not limited. The lower end of the wire drawing pipeline is provided with a coater for coating a high-reflection medium, and a take-up wheel is provided to wind the scintillation crystal fiber into a roll. Refer to Example 2 for the method of preparing the obtained columnar scintillation crystal fiber into a submillimeter-scale high-resolution scintillation crystal array.

Example 13

A sub-millimeter high-resolution bismuth germanate (Bi ₄ Ge ₃ O ₁₂ )-based scintillation crystal array was grown from the melt in one step using a mold with a specific structure based on the immersion solidification method. Arrange 0.2mm platinum wires with a length of 30mm on a 0.2mm platinum sheet of the same width evenly at a certain distance, with 100 pieces per layer arranged in 100 layers, press them into blocks, and place them in a muffle furnace at 1400 °C for 10 hours. After taking it out, it was immersed in a platinum crucible containing Bi ₄ Ge ₃ O ₁₂ melt, and then the platinum crucible was slowly lowered to make the melt in it solidify to form a crystal. ₄ Ge ₃ O ₁₂ sub-millimeter high-resolution scintillation crystal array. Platinum wire (diameter 0.1-1mm, length 5-500mm), platinum sheet size (thickness 0.1-1mm, width 5-500mm), number of layers (several to thousands of layers), and spacing (0.1-1mm) can be arbitrary Designed to meet high resolution scintillation crystal array pixel requirements.

Example 14

Submillimeter-scale high-resolution alkali metal iodide (NaI)-based scintillation crystal arrays were grown in one step by immersing a mold with a specific structure in the melt. The silver powder is formed into a block of 200×200×50mm ³ and placed in a 200Mpa isostatic press for compaction, and a square through hole with a side length of 0.5mm is punched out by a punching machine at a certain distance. Put it in a nitrogen atmosphere at 800 °C for 10 hours, and then take it out, immerse it in a quartz crucible containing NaI melt, and then slowly lower the quartz crucible to condense the melt to form crystals. Domain-grown NaI submillimeter-scale high-resolution scintillation crystal arrays.

Example 15

Submillimeter-scale high-resolution silicates (RE ₂ SiO ₅ , RE is a mixture of Lu, Y and Ce, Lu:Y:Ce=0.899:0.1: 0.001) based scintillation crystal array. The iridium powder is formed into a block of 300×300×20mm ³ and placed in a 200Mpa isostatic press for compaction, and a square through hole with a side length of 0.9mm is punched out by a punching machine at a certain distance. Put it in a nitrogen atmosphere at 1600 °C for 10 hours, take it out, immerse it in an iridium crucible containing RE ₂ SiO ₅ melt, and then slowly pull it out to let the melt in the hole condense to form a crystal, and wait until it is all pulled out of the melt, After cooling down, a sub-millimeter high-resolution scintillation crystal array is obtained.

Example 16

Submillimeter-scale high-resolution aluminate (RE ₃ Al ₅ O ₁₂ , RE is a mixture of Lu and Ce, Lu:Ce=0.995:0.005)-based scintillation is grown from the melt in one step using a mold with a specific structure based on the pull solidification method crystal array. The tungsten powder is formed into a block of 500×500×50mm ³ and placed in a 200Mpa isostatic press for compaction, and a drilling machine is used to punch non-penetrating holes of the same depth with a diameter of 0.2mm at a certain interval. It was placed in a vacuum furnace at 1500 °C for 2 hours, then raised to 2200 °C for 5 hours, taken out and immersed in a tungsten crucible containing RE ₃ Al ₅ O ₁₂ melt, and then slowly pulled out to allow the melt in the hole to condense After forming crystals, all of them are pulled out from the melt, and after cooling down, grinding the unperforated mold surface to expose the scintillation crystal pixel columns, thus obtaining a sub-millimeter high-resolution scintillation crystal array.

Example 17

Submillimeter-scale high-resolution rare earth sesquioxide (RE ₂ O ₃ , RE is a mixture of Lu, Eu, and Pr, Lu:Eu:Pr=0.945:0.05) : 0.005) based scintillation crystal array. The rhenium powder is formed into a block of 100×100×10mm ³ and placed in a 200Mpa isostatic press for compaction, and a drilling machine is used to punch non-penetrating holes of the same depth with a diameter of 0.3mm at a certain interval. It was placed in a vacuum furnace at 1500 °C for 2 hours, and then raised to 2500 °C for 5 hours. After taking it out, put RE ₂ O ₃ ceramics on the end with holes, and through induction heating, the RE ₂ O ₃ ceramics above the holes were melted and gradually flowed into the holes. Fill all the holes, and then slowly cool down to allow the melt in the holes to condense to form crystals. After cooling and cooling, grind the unperforated mold surface to expose the scintillation crystal pixel pillars to obtain a sub-millimeter high-resolution scintillation crystal array. .

Claims (10)

1. A submillimeter-level high-resolution scintillation crystal array, characterized in that it comprises: an array consisting of a plurality of scintillation crystal pixel columns with a diameter or side length of 0.1 to 1 mm, for separating each scintillation crystal pixel column The highly reflective medium layer and the light-shielding medium layer, as well as the mold for arranging and fixing the scintillation crystal pixel column to form an array, or the bonding matrix for arranging and fixing the scintillation crystal pixel column to form an array and distributed inside the array interval. 2 . The submillimeter high-resolution scintillation crystal array according to claim 1 , wherein the composition of the scintillation crystal pixel column comprises: rare earth sesquioxide-based scintillation crystal RE ₂ O ₃ , silicate-based scintillation crystal Scintillation crystals, aluminate-based scintillation crystals, aluminum gallate-based scintillation crystals RE ₃ Al _5x Ga _5-5x O ₁₂ , bismuth germanate-based scintillation crystals Bi ₄ Ge ₃ O ₁₂ , tungstate-based scintillation crystals, alkaline earth metals At least one of fluoride-based scintillation crystals, rare earth bromide-based scintillation crystals REBr ₃ , alkali metal iodide-based scintillation crystals, and alkaline-earth metal iodide-based scintillation crystals; wherein RE is rare earth ions including lanthanum (La), cerium (Ce ), praseodymium (Pr), europium (Eu), gadolinium (Gd), ytterbium (Yb), lutetium (Lu), scandium (Sc), and yttrium (Y). 3. The submillimeter high-resolution scintillation crystal array according to claim 2, wherein the silicate-based scintillation crystal is at least one of RE ₂ SiO ₅ and RE ₂ Si ₂ O ₇ ; The aluminate-based scintillation crystal is at least one of RE ₃ Al ₅ O ₁₂ and REAlO ₃ ; The tungstate-based scintillation crystal is at least one of PbWO _{4 , CdWO 4 ,} ZnWO ₄ , and CaWO ₄ ; The alkaline earth metal fluoride-based scintillation crystal is at least one of CaF ₂ and BaF ₂ ; The alkali metal iodide-based scintillation crystal is at least one of NaI and CsI; The alkaline earth metal iodide-based scintillation crystal is SrI ₂ . 4. The submillimeter-scale high-resolution scintillation crystal array according to claim 2 or 3, wherein when RE in the rare earth sesquioxide-based scintillation crystal RE ₂ O ₃ is selected from lanthanum (La), gadolinium (Gd) , lutetium (Lu), scandium (Sc), yttrium (Y) and at least one of cerium (Ce), praseodymium (Pr), europium (Eu), the cerium (Ce), praseodymium (Pr) ), the total content of at least one of europium (Eu) is 0.01 to 5 at.%; When RE is selected from lanthanum (La), gadolinium ( _Gd ), lutetium (Lu ), scandium (Sc), and yttrium (Y) and at least one of cerium (Ce), praseodymium (Pr), europium (Eu), and ytterbium (Yb), the cerium (Ce), praseodymium ( The total content of at least one of Pr), europium (Eu), and ytterbium (Yb) is 0.01 to 5 at.%; The alkali metal iodide-based scintillation crystal and the alkaline earth metal iodide-based scintillation crystal are doped with at least one of thallium (Tl) and europium (Eu). The total content is 0～5 at.%. 5 . The submillimeter high-resolution scintillation crystal array according to claim 1 , wherein the cross-sectional shape of the scintillation crystal pixel column is a circle, a square, or a rectangle, preferably a square. 6 . 6. The submillimeter high-resolution scintillation crystal array according to any one of claims 1 to 5, wherein the composition of the high-reflection medium layer is selected from materials with a reflectivity of ≥95% in the visible light region, including metals , at least one of barium sulfate, titanium dioxide, photonic crystal, Teflon, ESR reflective film, the metal is at least one of magnesium, aluminum, gallium, indium, tin, zinc, silver, platinum, ruthenium, osmium, iridium, rhenium One; the thickness of the high-reflection medium layer is 0.1-500 microns; The light-shielding medium layer is a high atomic coefficient light-absorbing material, at least one selected from lead, tungsten, and tantalum; the light-shielding medium layer has a thickness of 0-500 microns. 7. The submillimeter high-resolution scintillation crystal array according to any one of claims 1-6, wherein the material of the mold is selected from the group consisting of tungsten, lead, tantalum, ruthenium, osmium, iridium, rhenium, special At least one of fluorocarbon and polyvinyl chloride; The bonding matrix is selected from at least one of epoxy resin, silicone resin, polyacrylic resin, polyethylene glycol resin, polyvinyl butyral resin, polyvinyl alcohol resin, and polyimide resin; The thickness of the bonding matrix is 1-200 microns. 8. A method for preparing a sub-millimeter high-resolution scintillation crystal array according to any one of claims 1-7, characterized in that, comprising: (1) Using single crystal growth technology to directly grow elongated scintillation crystal fibers with a size of 0.1 to 1 mm as scintillation crystal pixel columns; (2) Prepare a high-reflection medium layer and a light-shielding medium layer on the surface of the scintillation crystal pixel column by in-situ growth or secondary processing; (3) The scintillation crystal pixel crystal columns with the highly reflective medium layer and the light-shielding medium layer are bundled and bonded by a bonding matrix or fixedly arranged by a mold to form an array, that is, a sub-millimeter high-resolution scintillation crystal array is obtained. 9. A method for preparing a submillimeter-level high-resolution scintillation crystal array according to any one of claims 1-7, characterized in that, comprising: (1) Using the structure of a submillimeter high-resolution scintillation crystal array to prepare a mold with a submillimeter aperture array structure skeleton, the mold with a submillimeter aperture array structure skeleton is composed of at least one of the high reflection medium layer and the light blocking medium layer; One, and the melting point of the mold with the sub-millimeter aperture array structure skeleton > the melting point of the scintillation crystal pixel crystal column; (2) Immerse the mold with the submillimeter aperture array structure skeleton in the melt of the scintillation crystal pixel crystal column, and grow the submillimeter high-resolution scintillation crystal array with a high reflection medium or a light-blocking medium through a one-step method. 10 . The application of the sub-millimeter high-resolution scintillation crystal array according to any one of claims 1 to 7 in X-ray flash photography and medical imaging. 11 .

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