A lutetium orthosilicate single crystal having a crystal plane orientation and a method for manufacturing the same

Abstract

The application discloses a lutetium silicate single crystal with crystal face orientation and a preparation method thereof, and the preparation method comprises the following steps: preparing a cerium-doped lutetium silicate precursor by a sol-gel method, the cerium-doped lutetium silicate can be simply referred to as LSO:Ce; calcining the LSO:Ce at 1000 DEG C for 2 hours to obtain LSO:Ce ceramic powder; and forming a green body by dry pressing and cold isostatic pressing of the synthesized LSO:Ce powder and lutetium yttrium silicate single crystal with crystal face orientation; then, high-temperature and high-pressure sintering is carried out under an argon atmosphere, in the sintering process, the crystal grains grow continuously along the seed crystal by solid phase diffusion, single crystallization occurs under the solid state condition, and finally, the directional LSO:Ce single crystal is obtained. The prepared directional LSO:Ce single crystal has the characteristics of compact structure, controllable crystal size, thick single crystal layer, and no element segregation, can be grown on both sides, and has the advantages of replacing Lu with other rare earth elements or doping different proportions of rare earth elements.

Description

Technical Field

[0001] This application belongs to the field of single crystal growth technology, specifically relating to a lutetium silicate single crystal with crystal orientation and its preparation method. Background Technology

[0002] Scintillation crystals are increasingly widely used in nuclear detection technologies, primarily in X-ray computed tomography (XCT), positron emission tomography (PET), industrial computed tomography (ICT), oil well exploration, concealed explosives detection, nuclear physics, and high-energy physics. Cerium-doped lutetium silicate (LSO:Ce) crystals are high-performance scintillation crystals, particularly suitable for PET devices. LSO:Ce scintillators possess excellent overall performance (high density, high effective atomic number, fast decay, and high light yield), making them suitable for a wide range of potential applications in gamma-ray detectors. Many research institutions and companies have intensified their research on LSO:Ce. Currently, although commercial PET is available on the market, LSO:Ce crystals have not yet achieved a dominant position in the scintillation crystal field due to both technological and market factors. Because LSO has a high melting point of 2000–2100℃, which is close to the limit of iridium crucibles and insulation materials, crystal growth is extremely difficult. Furthermore, the difference in thermal expansion coefficients between the seed crystal and the iridium rod during crystal growth can lead to crystal cracking. In addition, LSO crystals are typically grown using the Czochralski method, and due to the difference in atomic radii between Ce and Lu, its segregation coefficient is 0.22, resulting in extremely uneven distribution of Ce in the crystal, with a lower content in the early stages of growth than in the later stages. The University of California, Los Angeles, has prepared polycrystalline powder with the crystalline phase Lu₂SiO₅ using the sol-gel method, and its scintillation properties are close to those of single crystals grown by the Czochralski method. This method has relatively low processing temperatures, controllable stoichiometry, and atomic-scale uniformity. In recent years, more and more researchers have prepared single crystals using solid-state crystal growth methods. In this solid-state method, the single crystal is grown in a non-molten state, thus avoiding the phenomenon of dopant ion segregation, which is advantageous compared to single crystals prepared by traditional melt growth and solution growth methods. Simultaneously, it achieves a crystal growth rate greater than that of the CZ method using the SSCG method. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems. This application provides a method for preparing lutetium silicate single crystals with crystal orientation by hot-pressing and sintering fine-grained lutetium silicate powder prepared by the sol-gel method in an argon atmosphere and then using a solid-state crystal growth method.

[0004] Technical Solution: To solve the above-mentioned technical problems and achieve the above-mentioned objectives, this invention proposes a method for preparing lutetium silicate single crystals with crystal plane orientation. The preparation method includes the following steps:

[0005] (1) A cerium-doped lutetium silicate precursor was prepared by sol-gel method, and coarse-grained (Lu) silicate was obtained by calcination at 1000℃ for 2 h. 0.995 Ce 0.005 L2SiO5 ceramic powder, abbreviated as LSO:Ce;

[0006] (2) Prepare (Lu) 0.995 Ce 0.005 LSO:Ce ceramic powder with deagglomerated fine grains was obtained by ball milling 2SiO5 ceramic powder with alcohol as the dispersion medium for 24 hours.

[0007] (3) A single crystal of yttrium lutetium silicate with grain orientation is placed in fine-grained LSO:Ce ceramic powder, and a green body of fine-grained LSO:Ce ceramic powder wrapped with yttrium lutetium silicate single crystal is prepared by dry pressing. The forming pressure is 8-10 MPa. After cold isostatic pressing at 180 MPa, the green body of the single crystal is further densified.

[0008] (4) The green blank obtained in step (3) is placed in a graphite crucible and sintered in an argon atmosphere at 1650-1780℃ and 30-80 MPa pressure to obtain LSO:Ce single crystals oriented along the orientation plane of yttrium silicate single crystals.

[0009] Furthermore, in step (1), the lutetium silicate precursor powder is calcined at 1000°C for 2 hours to obtain X1 type LSO:Ce ceramic powder.

[0010] Further, in step (1), the sol-gel method is as follows: Lu2O3 powder with a purity greater than 99.99% is dissolved in hydrochloric acid, wherein the molar ratio of Cl to Lu is 6:1, CeCl3 solution with a Ce content of 0.5 at.% is added and stirred, and LuCl3·6H2O is obtained by rotary evaporation, isopropanol, propylene oxide and tetraethyl orthosilicate are added, wherein the amount of tetraethyl orthosilicate is half the amount of Lu and Ce, mechanically stirred for 48h, and then dried in an 80℃ forced-air drying oven for 24h to obtain the precursor.

[0011] Furthermore, in step (2), the mass ratio of LSO:Ce ceramic powder to zirconia ball mill balls is 1:6, the amount of alcohol is the same as the amount of powder, the rotation speed of the planetary ball mill is 250 rpm, and the median particle size of the fine grain powder after 24 hours of ball milling is 142 nm.

[0012] Further, the dry pressing method described in step (3) is as follows: a certain amount of LSO:Ce ceramic powder is added to a stainless steel mold for pre-pressing, the pre-pressing pressure is 2MPa, the yttrium lutetium silicate single crystal is placed directly above the LSO:Ce green blank in the mold, a certain amount of LSO:Ce ceramic powder is added to cover the yttrium lutetium silicate single crystal, and then the mold is pressed with a pressure of 8-10MPa.

[0013] Furthermore, in step (3), the density of the green body is 50-55%.

[0014] Furthermore, the sintering process in step (4) involves raising the temperature from room temperature to 1000℃ at 5℃ / min, applying a pressure of 20-100MPa at 800℃, raising it to 1650-1780℃ at 10℃ / min, holding it at that temperature for 6 hours, and then lowering it to 1000℃ at 5℃ / min before water cooling.

[0015] Furthermore, the present invention also proposes a lutetium silicate single crystal with crystal plane orientation, wherein the lutetium silicate single crystal with crystal plane orientation is prepared by any of the above preparation methods.

[0016] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0017] (1) This application uses the sol-gel method to prepare lutetium silicate powder, which can accurately control the stoichiometric ratio of lutetium and cerium.

[0018] (2) This application uses calcination at 1000℃ for 2 hours to obtain fine-grained LSO:Ce ceramic powder.

[0019] (3) This application uses a combination of dry pressing and cold isostatic pressing to produce a green blank with high density.

[0020] (4) The single crystal structure produced by the solid crystal growth method in this application is dense, the size of the grown crystal is controllable, the single crystal layer is thick, and there is no element segregation. Attached Figure Description

[0021] Figure 1 (Lu) was obtained by calcining precursor powder at 1000℃ and holding for 2 hours. 0.995 Ce 0.005 XRD pattern of 2SiO5 powder.

[0022] Figure 2 This is a particle size distribution diagram of the powder after ball milling for 24 hours.

[0023] Figure 3 The image shows the XRD pattern of a single crystal of lutetium silicate with oriented crystal planes in Embodiment 1 of the present invention.

[0024] Figure 4The image shows the XRD pattern of a single crystal of lutetium silicate with oriented crystal planes in Embodiment 2 of the present invention.

[0025] Figure 5 The image shows the XRD pattern of a single crystal of lutetium silicate with oriented crystal planes in Embodiment 3 of the present invention. Detailed Implementation

[0026] To better illustrate the purpose, technical solution, and advantages of this application, specific examples will be used to further explain them below.

[0027] In the technical solution of this application, lutetium silicate single crystals with crystal orientation can be prepared by following the steps below:

[0028] (1) Lu2O3 powder with a purity greater than 99.99% was dissolved in hydrochloric acid, wherein the molar ratio of Cl to Lu was 6:1. A CeCl3 solution with a Ce content of 0.5 at.% was added and stirred. The mixture was then rotary evaporated to obtain LuCl3·6H2O. Isopropanol, propylene oxide, and tetraethyl orthosilicate were then added, wherein the amount of tetraethyl orthosilicate was half the amount of Lu and Ce. After mechanical stirring for 48 h, the mixture was dried in an 80℃ forced-air drying oven for 24 h to obtain the precursor.

[0029] (2) After calcining at 1000℃ for 2h, coarse-grained X1 type LSO:Ce ceramic powder was obtained. The prepared coarse-grained powder was then processed with a mass ratio of LSO:Ce powder to zirconia ball milling pellets of 1:6, with the amount of alcohol being the same as the amount of powder. The rotation speed of the planetary ball mill was 250rpm. After ball milling for 24h, the median particle size of the fine-grained powder was 142nm.

[0030] (3) A single crystal of yttrium lutetium silicate with grain orientation is placed in fine-grained LSO:Ce ceramic powder, and a green body of fine-grained LSO:Ce powder encapsulating the single crystal of yttrium lutetium silicate is prepared by dry pressing. The pressing pressure is 8-10 MPa, and then it is subjected to cold isostatic pressing at 180 MPa to further densify the green body of the single crystal. The density of the green body is 50-55%.

[0031] (4) Place the green blank in a graphite mold and raise it from room temperature to 1000℃ at 5℃ / min in an argon atmosphere or vacuum. Apply a pressure of 20-100MPa at 800℃, then raise it to 1650-1780℃ at 10℃ / min. After holding it at this temperature for 6 hours, lower it to 1000℃ at 5℃ / min and then cool it naturally with water to obtain LSO:Ce single crystals oriented along the orientation crystal plane of yttrium silicate single crystals.

[0032] The following will describe the preparation process of a single crystal of lutetium silicate with crystal orientation using specific examples.

[0033] Example 1

[0034] (a) Weigh 138.422 g of lutetium oxide powder into a beaker, add 422.2 g of hydrochloric acid, and dissolve it completely by magnetic stirring at 80 °C. Then add 9.98 ml of 0.35 mol / L CeCl3 solution and transfer the entire solution to a round-bottom flask. Evaporate the solution under rotary evaporation conditions of 55–85 °C and a vacuum degree below 0.02 MPa to obtain LuCl3·6H2O and CeCl3·7H2O. Immediately after removing the round-bottom flask, seal it with plastic wrap to prevent moisture absorption. Weigh the total mass of the sealed round-bottom flask, LuCl3·6H2O, and CeCl3·7H2O crystals. The mass of LuCl3·6H2O and CeCl3·7H2O in the flask can be determined. Based on the previously added Lu... 3+ The quantities were used to calculate the theoretical mass of LuCl3·6H2O and CeCl3·7H2O, and the evaporation effect was judged.

[0035] (b) After weighing, remove the plastic wrap and immediately add isopropanol to the round-bottom flask and shake. Transfer the mixture of LuCl3·6H2O, CeCl3·7H2O, and isopropanol to a beaker, and repeatedly wash the flask with isopropanol. Transfer the washing liquid to a large beaker as well. Continue to add isopropanol until the volume reaches 2058 ml, and continue to disperse by mechanical stirring for half an hour. After LuCl3·6H2O and CeCl3·7H2O are evenly dispersed in isopropanol, add 73.34 g of TEOS to the large beaker. Rinse the beaker containing the weighed TEOS with propylene oxide, and continue to add propylene oxide until the volume reaches 1029 ml. Continue to stir mechanically for 48 hours until the reaction is complete to obtain the precursor. Calcine the precursor at 1000℃ for 2 hours to obtain X1 type LSO:Ce powder. The XRD pattern of the powder is as follows: Figure 1 As shown.

[0036] (c) The calcined X1 type LSO:Ce ceramic powder was added to the zirconia ball mill jar at a mass ratio of LSO:Ce powder to zirconia ball mill balls of 1:6. Anhydrous ethanol was used as the ball milling medium. An appropriate amount of anhydrous ethanol was added according to the solid content of the powder of 30 vol.%. The ball mill was carried out at a speed of 250 rpm for 24 hours. After the ball milling was completed, the ball mill jar was placed in a forced-air drying oven and dried at 80°C for 24 hours.

[0037] (d) The particle size of the ball-milled powder was measured to be 142 nm using a nanoparticle size analyzer. The particle size distribution of the powder after ball milling is as follows: Figure 2 As shown.

[0038] (e) 4.5g of ball-milled and dried LSO:Ce powder was added to a stainless steel mold with a diameter of 20mm and pre-pressed at a pressure of 2MPa for 10s. Then, a yttrium lutetium silicate single crystal was placed directly above the LSO:Ce green in the mold, and 5.5g of LSO:Ce powder was added to cover the yttrium lutetium silicate single crystal. The mold was then pressed at a pressure of 10MPa and then subjected to cold isostatic pressing at 180MPa to further densify the green covered with the single crystal. The green density was 55% and the diameter was 18.8mm.

[0039] (f) A layer of BN was sprayed into the inner cavity of a 20mm diameter graphite mold to facilitate demolding. Then, 1g of LSO:Ce powder was evenly spread inside. The pressed green body was then placed in the center of the mold, and another 2g of LSO:Ce powder was added. The graphite mold was placed in a vacuum hot press furnace for sintering. The temperature was increased from room temperature to 1000℃ at 5℃ / min in an argon atmosphere. A pressure of 40MPa was applied at 800℃, and then the temperature was increased to 1700℃ at 10℃ / min. After holding at this temperature for 6 hours, the temperature was decreased to 1000℃ at 5℃ / min and then naturally cooled by water. This yielded an LSO:Ce single crystal oriented along the crystal orientation plane of lutetium yttrium silicate, with a growth layer thickness of 1.8mm. The XRD pattern of the sintered lutetium silicate single crystal is shown in the figure. Figure 3 As shown, the texture factor of the (-112) crystal plane direction calculated by XRD data reaches 92.6%.

[0040] Example 2

[0041] (a) Weigh 138.422 g of lutetium oxide powder into a beaker, add 422.2 g of hydrochloric acid, and dissolve it completely by magnetic stirring at 80 °C. Then add 9.98 ml of 0.35 mol / L CeCl3 solution and transfer the entire solution to a round-bottom flask. Evaporate the solution under rotary evaporation conditions of 55–85 °C and a vacuum degree below 0.02 MPa to obtain LuCl3·6H2O and CeCl3·7H2O. Immediately after removing the round-bottom flask, seal it with plastic wrap to prevent moisture absorption. Weigh the total mass of the sealed round-bottom flask, LuCl3·6H2O, and CeCl3·7H2O crystals. The mass of LuCl3·6H2O and CeCl3·7H2O in the flask can be determined. Based on the previously added Lu... 3+ The quantities were used to calculate the theoretical mass of LuCl3·6H2O and CeCl3·7H2O, and the evaporation effect was judged.

[0042] (b) After weighing, remove the plastic wrap and immediately add isopropanol to the round-bottom flask and shake. Transfer the mixture of LuCl3·6H2O, CeCl3·7H2O, and isopropanol to a beaker, and repeatedly wash the flask with isopropanol. Transfer the washing liquid to a large beaker as well. Continue to add isopropanol until the volume reaches 2058 ml, and continue to disperse by mechanical stirring for half an hour. After LuCl3·6H2O and CeCl3·7H2O are evenly dispersed in isopropanol, add 73.34 g of TEOS to the large beaker. Rinse the beaker containing the weighed TEOS with propylene oxide, and continue to add propylene oxide until the volume reaches 1029 ml. Continue to stir mechanically for 48 hours until the reaction is complete to obtain the precursor. Calcine the precursor at 1000℃ for 2 hours to obtain X1 type LSO:Ce powder. The XRD pattern of the powder is as follows: Figure 1 As shown.

[0043] (c) The calcined X1 type LSO:Ce ceramic powder was added to the zirconia ball mill jar at a mass ratio of LSO:Ce powder to zirconia ball mill balls of 1:6. Anhydrous ethanol was used as the ball milling medium. An appropriate amount of anhydrous ethanol was added according to the solid content of the powder of 30 vol.%. The ball mill was carried out at a speed of 250 rpm for 24 hours. After the ball milling was completed, the ball mill jar was placed in a forced-air drying oven and dried at 80°C for 24 hours.

[0044] (d) The particle size of the ball-milled powder was measured to be 142 nm using a nanoparticle size analyzer. The particle size distribution of the powder after ball milling is as follows: Figure 2 As shown.

[0045] (e) 4.5g of ball-milled and dried LSO:Ce powder was added to a stainless steel mold with a diameter of 20mm and pre-pressed at a pressure of 2MPa for 10s. Then, a yttrium lutetium silicate single crystal was placed directly above the LSO:Ce green blank in the mold, and 5.5g of LSO:Ce powder was added to cover the yttrium lutetium silicate single crystal. The green blank was then pressed and shaped under a pressure of 10MPa to further densify the green blank covered with the single crystal. The density of the green blank was 55% and the diameter was 18.8mm.

[0046] (f) A layer of BN was sprayed into the inner cavity of a 20mm diameter graphite mold to facilitate demolding. Then, 1g of LSO:Ce powder was evenly spread inside. The pressed green body was then placed in the center of the mold, and another 2g of LSO:Ce powder was added. The graphite mold was placed in a vacuum hot press furnace for sintering. The temperature was increased from room temperature to 1000℃ at 5℃ / min in an argon atmosphere. A pressure of 30MPa was applied at 800℃, and then the temperature was increased to 1700℃ at 10℃ / min. After holding at this temperature for 6 hours, the temperature was decreased to 1000℃ at 5℃ / min and then naturally cooled by water. This yielded an LSO:Ce single crystal oriented along the crystal plane of lutetium silicate, with a growth layer thickness of 1mm. The XRD pattern of the sintered lutetium silicate single crystal is shown below. Figure 4As shown, the texture factor of the (-606) crystal plane direction calculated by XRD data reaches 41.1%.

[0047] Example 3

[0048] (a) Weigh 138.422 g of lutetium oxide powder into a beaker, add 422.2 g of hydrochloric acid, and dissolve it completely by magnetic stirring at 80 °C. Then add 9.98 ml of 0.35 mol / L CeCl3 solution and transfer the entire solution to a round-bottom flask. Evaporate the solution under rotary evaporation conditions of 55–85 °C and a vacuum degree below 0.02 MPa to obtain LuCl3·6H2O and CeCl3·7H2O. Immediately after removing the round-bottom flask, seal it with plastic wrap to prevent moisture absorption. Weigh the total mass of the sealed round-bottom flask, LuCl3·6H2O, and CeCl3·7H2O crystals. The mass of LuCl3·6H2O and CeCl3·7H2O in the flask can be determined. Based on the previously added Lu... 3+ The quantities were used to calculate the theoretical mass of LuCl3·6H2O and CeCl3·7H2O, and the evaporation effect was judged.

[0049] (b) After weighing, remove the plastic wrap and immediately add isopropanol to the round-bottom flask and shake. Transfer the mixture of LuCl3·6H2O, CeCl3·7H2O, and isopropanol to a beaker, and repeatedly wash the flask with isopropanol. Transfer the washing liquid to a large beaker as well. Continue to add isopropanol until the volume reaches 2058 ml, and continue to disperse by mechanical stirring for half an hour. After LuCl3·6H2O and CeCl3·7H2O are evenly dispersed in isopropanol, add 73.34 g of TEOS to the large beaker. Rinse the beaker containing the weighed TEOS with propylene oxide, and continue to add propylene oxide until the volume reaches 1029 ml. Continue to stir mechanically for 48 hours until the reaction is complete to obtain the precursor. Calcine the precursor at 1000℃ for 2 hours to obtain X1 type LSO:Ce powder. The XRD pattern of the powder is as follows: Figure 1 As shown.

[0050] (c) The calcined X1 type LSO:Ce ceramic powder was added to the zirconia ball mill jar at a mass ratio of LSO:Ce powder to zirconia ball mill balls of 1:6. Anhydrous ethanol was used as the ball milling medium. An appropriate amount of anhydrous ethanol was added according to the solid content of the powder of 30 vol.%. The ball mill was carried out at a speed of 250 rpm for 24 hours. After the ball milling was completed, the ball mill jar was placed in a forced-air drying oven and dried at 80°C for 24 hours.

[0051] (d) The particle size of the ball-milled powder was measured to be 142 nm using a nanoparticle size analyzer. The particle size distribution of the powder after ball milling is as follows: Figure 2 As shown.

[0052] (e) 4.5g of ball-milled and dried LSO:Ce powder was added to a stainless steel mold with a diameter of 20mm and pre-pressed at a pressure of 2MPa for 10s. Then, a yttrium lutetium silicate single crystal was placed directly above the LSO:Ce green in the mold, and 5.5g of LSO:Ce powder was added to cover the yttrium lutetium silicate single crystal. The mold was then pressed at a pressure of 10MPa and then subjected to cold isostatic pressing at 180MPa to further densify the green covered with the single crystal. The green density was 55% and the diameter was 18.8mm.

[0053] (f) A layer of BN was sprayed into the inner cavity of a 20mm diameter graphite mold to facilitate demolding. Then, 1g of LSO:Ce powder was evenly spread inside. The pressed green body was then placed in the center of the mold, and another 2g of LSO:Ce powder was added. The graphite mold was sintered in a vacuum hot press furnace. The temperature was increased from room temperature to 1000℃ at 5℃ / min in an argon atmosphere. A pressure of 40MPa was applied at 800℃, and then the temperature was increased to 1700℃ at 10℃ / min. After holding at this temperature for 6 hours, the temperature was decreased to 1000℃ at 5℃ / min and then naturally cooled by water. This yielded an LSO:Ce single crystal oriented along the crystal plane of lutetium yttrium silicate, with a growth layer thickness of 1.2mm. The XRD pattern of the sintered lutetium silicate single crystal is shown below. Figure 5 As shown, the texture factor of the (-325) crystal plane direction calculated by XRD data reaches 67.1%.

[0054] Finally, it should be noted that those skilled in the art will understand that many technical details have been presented in the embodiments of this application to facilitate a better understanding of the present application. However, even without these technical details and various changes and modifications based on the above embodiments, the technical solutions claimed in the claims of this application can be substantially achieved. Therefore, in practical applications, various changes can be made to the above embodiments in form and detail without departing from the spirit and scope of this application.

Claims

1. A method for preparing lutetium silicate single crystals with crystal plane orientation, characterized in that, The preparation method includes the following steps: (1) Ce-doped Lu2SiO5 precursor was prepared by sol-gel method, and coarse-grained Lu6.75Ce0.25SiO5 ceramic powder (abbreviated as LSO:Ce) was obtained by calcining at 1000℃ for 2h. 0.995 Ce 0.005 )2SiO5 ceramic powder. (2) Prepare (Lu) 0.995 Ce 0.005 LSO:Ce ceramic powder with deagglomerated fine grains was obtained by ball milling 2SiO5 ceramic powder with alcohol as the dispersion medium for 24 hours. (3) A single crystal of yttrium lutetium silicate with grain orientation is placed in fine-grained LSO:Ce ceramic powder, and a green body of fine-grained LSO:Ce ceramic powder wrapped with yttrium lutetium silicate single crystal is prepared by dry pressing. The forming pressure is 8-10 MPa. After cold isostatic pressing at 180 MPa, the green body of the single crystal is further densified. (4) The green blank obtained in step (3) is placed in a graphite crucible and sintered in an argon atmosphere at 1650-1780℃ and 30-80 MPa pressure to obtain LSO:Ce single crystals oriented along the orientation plane of yttrium silicate single crystals.

2. The preparation method according to claim 1, characterized in that, In step (1), the lutetium silicate precursor powder is calcined at 1000℃ for 2 hours to obtain X1 type LSO:Ce ceramic powder.

3. The preparation method according to claim 1, characterized in that, In step (1), the sol-gel method is as follows: Lu2O3 powder with a purity greater than 99.99% is dissolved in hydrochloric acid, wherein the molar ratio of Cl to Lu is 6:

1. CeCl3 solution with a Ce content of 0.5 at.% is added and stirred. LuCl3·6H2O is obtained by rotary evaporation. Isopropanol, propylene oxide and tetraethyl orthosilicate are added, wherein the amount of tetraethyl orthosilicate is half the amount of Lu and Ce. After mechanical stirring for 48 hours, the precursor is dried in an 80°C forced-air drying oven for 24 hours.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of LSO:Ce ceramic powder to zirconia ball mill balls is 1:6, the amount of alcohol is the same as the amount of powder, the rotation speed of the planetary ball mill is 250 rpm, and the median particle size of the fine grain powder after 24 hours of ball milling is 142 nm.

5. The preparation method according to claim 1, characterized in that, The dry pressing method described in step (3) is as follows: a certain amount of LSO:Ce ceramic powder is added to a stainless steel mold for pre-pressing. The pre-pressing pressure is 2MPa. The yttrium lutetium silicate single crystal is placed directly above the LSO:Ce green blank in the mold. A certain amount of LSO:Ce ceramic powder is added to cover the yttrium lutetium silicate single crystal. Then, the mold is pressed with a pressure of 8-10MPa.

6. The preparation method according to claim 1, characterized in that, In step (3), the density of the green body is 50-55%.

7. The preparation method according to claim 1, characterized in that, The sintering process in step (4) involves raising the temperature from room temperature to 1000℃ at 5℃ / min, applying a pressure of 20-100MPa at 800℃, raising it to 1650-1780℃ at 10℃ / min, holding it at that temperature for 6 hours, and then lowering it to 1000℃ at 5℃ / min before water cooling.

8. A lutetium silicate single crystal with crystal plane orientation, characterized in that, The lutetium silicate single crystal with crystal orientation is prepared by any one of claims 1 to 7.

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