Chromium ion doped near-infrared scintillation crystal and preparation method and application thereof

Abstract

The invention belongs to the technical field of scintillation materials, and particularly relates to a chromium ion doped near-infrared scintillation crystal and a preparation method and application thereof. The chromium ion-doped near-infrared scintillation crystal has a molecular formula of A3B2-xCrxC3O12, x is greater than or equal to 0.005 and less than or equal to 0.1, and after a chromium ion-doped ultraviolet-visible light inorganic scintillator is adopted, light is emitted at the wavelength of 650-950 nm and has good wavelength matching with a silicon photoelectric detector. Besides, single crystal growth is carried out by adopting a Czochralski method, the crystal growth process is optimized, the ion doping concentration is regulated and controlled, the scintillation performance of the chromium ion doped near-infrared scintillation crystal in the near-infrared band is improved, the requirement of the chromium ion doped near-infrared scintillation crystal in the radiation detection field is further met, and the problem that an existing scintillation crystal is low in transparency is solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of scintillation materials, and particularly relates to a chromium ion doped near-infrared scintillation crystal as well as a preparation method and application thereof. BACKGROUND

[0002] A photomultiplier tube is an early photoelectric conversion device, and its optimal response wavelength range is about 400 nm. An inorganic scintillator in the prior art will emit ultraviolet-visible light under the action of high-energy rays or high-energy particles. Since the inorganic scintillator needs to be coupled with the photomultiplier tube and assembled into a scintillation crystal detector for use, the light-emitting wavelength of the inorganic scintillator needs to match the wavelength of the optimal response of the photoelectric conversion device, and the quantum efficiency of the photoelectric conversion device largely determines the performance of the scintillation crystal detector. At present, the matching degree of the detection sensitive area of the commercial inorganic scintillator and the photomultiplier tube is good, and the scintillation crystal detector prepared by using the inorganic scintillator is widely used in the fields of high-energy physics, nuclear medicine, safety inspection, geological exploration and industrial flaw detection.

[0003] In recent years, with the rapid development of silicon photodetector technology, photoelectric conversion devices with an optimal response wavelength range in the red light-near infrared appear, and the red light-near infrared wavelength is 600 nm-1100 nm. For example, an avalanche photodiode has a quantum efficiency of 80% at 700 nm-800 nm, which is 2-3 times higher than that of a photomultiplier tube with a highest quantum efficiency of about 30%, and has the advantages of high signal-to-noise ratio, fast time response, magnetic field insensitivity, low price and small size. Therefore, developing a detector based on a near-infrared scintillation crystal and applying it has become a technical hotspot.

[0004] The luminescence wavelength of a large-size intrinsic luminescence Cs2HfI6 crystal in the prior art is in the red light band, and the energy resolution can reach 4.2% under the excitation of 662 keV rays, which has excellent scintillation performance and anti-hydration characteristics, and is the closest red light scintillation crystal material to commercialization at present. However, due to the difficulty in separating Hf elements from Zr elements, the high-purity HfI4 raw material is difficult to obtain and has high preparation cost, which affects the wide application of the Cs2HfI6 crystal.

[0005] The scintillation crystal doped with Sm 2+ has the problems of low light yield and poor energy resolution, so the research on red light-near infrared luminescence scintillation crystals has gradually shifted to a co-doped system in recent years. Some Eu 2+ doped halide crystals have high light yield and excellent energy resolution, but have a serious self-absorption problem. The modification by co-doping Eu 2+ -Sm 2+ can realize red light-near infrared luminescence, and the Eu 2+ to Sm 2+The energy transfer effect of the Cr3+ ion, the main emission peak is red-shifted, and the emission intensity of the Sm3+ ion is higher than that of the single-doped Sm 2+ The system exhibits better gamma ray detection performance, however, due to the differences in ion radius, coordination environment and segregation coefficient, co-doping has a significant influence on the crystal growth process, defect distribution and luminescence uniformity, such as the problems of easy cracking of the crystal and reduction of light output.

[0006] It can be seen that the prior art generally has the problems of expensive near-infrared scintillation crystal, low performance of single-doped crystal, and high performance of double-doped crystal but causing crystal defects. SUMMARY

[0007] In view of the above problems in the prior art, the present application provides a chromium ion doped near-infrared scintillation crystal and a preparation method and application thereof. 2-x Cr x C3O 12 , and 0.005≤x≤0.1; wherein A is a rare earth element; B is selected from one of Al, Sc and Ga; and C is selected from one of Al, Ga and In.

[0008] Based on the above technical purposes, the present application adopts the following technical solutions: The present application protects the chromium ion doped near-infrared scintillation crystal, and the molecular formula of the chromium ion doped near-infrared scintillation crystal is A3B 2-x Cr x C3O 12 , and 0.005≤x≤0.1; wherein A is a rare earth element; B is selected from one of Al, Sc and Ga; and C is selected from one of Al, Ga and In.

[0009] Preferably, the chromium ion doped near-infrared scintillation crystal can emit broadband near-infrared light with a wavelength of 650nm-950nm under excitation; the average transmittance of the chromium ion doped near-infrared scintillation crystal reaches 77% in the 750nm-1000nm waveband; the chromium ion doped near-infrared scintillation crystal has a high transmittance after 700nm, i.e. has a high transmittance in the near-infrared waveband, and does not affect the emission of near-infrared light.

[0010] Preferably, the wavelength of the chromium ion doped near-infrared scintillation crystal matches the detection wavelength of the APD detector, and the wavelength of the chromium ion doped near-infrared scintillation crystal is within the detection range of the APD detector.

[0011] The application also protects a preparation method of the chromium ion doped near-infrared scintillation crystal, comprising the following steps: The stoichiometric ratio of the oxides A, the oxides B, the oxides C and the chromium oxide is weighed according to the molecular formula A3B 2-x Cr x C3O 12 The purity of the oxides A, the oxides B, the oxides C and the chromium oxide is higher than 99.99%, and the powder raw material is obtained by uniformly mixing.

[0012] The powder raw material is calcined in an aerobic environment to obtain a polycrystalline material.

[0013] The polycrystalline material is subjected to single crystal growth by a melt pulling method to obtain a single crystal material.

[0014] The single crystal material is annealed in air to obtain the chromium ion doped near-infrared scintillation crystal.

[0015] Preferably, the calcination condition is that the calcination is performed at 1300℃-1500℃ for 24h-48h.

[0016] Preferably, the operation of the melt pulling method is that the polycrystalline material is heated to be melted, a seed crystal is lowered, the crystal is pulled after the power is stabilized, the pulling rate is 1mm / h, the rotation speed is 8rpm-12rpm, and the single crystal material is obtained by sequentially passing through necking, shoulder release, equal-diameter growth, tailing, and pulling-off.

[0017] Preferably, the seed crystal is a directional seed crystal in the <111> direction.

[0018] Preferably, the atmosphere for the single crystal growth is a mixed atmosphere of argon and carbon dioxide, and the volume ratio of the argon to the carbon dioxide is 3-9:1.

[0019] Preferably, the container for the single crystal growth is an iridium gold crucible, the melting point of the iridium gold is 2454℃, which can withstand the high temperature required for the melting of the polycrystalline material, the melting point of the polycrystalline material is 1800℃, so the iridium gold crucible with a higher melting point is selected.

[0020] Preferably, the annealing condition is that the annealing is performed at 1300℃-1500℃ for 24h-48h.

[0021] The application also protects the application of the chromium ion doped near-infrared scintillation crystal in the preparation of a scintillation material.

[0022] Compared with the prior art, the application has the following beneficial effects: 1. This invention employs chromium ion-doped ultraviolet-visible inorganic scintillators to obtain chromium ion-doped near-infrared scintillator crystals. The reason for using chromium ion doping is that chromium ions possess a tunable emission spectrum within the 650nm~1600nm range and a wide absorption range covering almost the entire ultraviolet-visible region, making them ideal near-infrared emission centers. Furthermore, through the doping of chromium ions... 4 T 2g - 4 A 2g Spin-allowed transitions can effectively achieve near-infrared emission.

[0023] This invention yields a chromium ion-doped near-infrared scintillation crystal with the chemical formula: A3B. 2-x Cr x C3O 12 ,0.005≤x≤0.1,After adopting chromium ion doping, the problems of existing ultraviolet-visible inorganic scintillators are overcome. The reasons for overcoming are: (1) Structural order: Chromium ion doped near-infrared scintillator crystals have regular atomic arrangement, which reduces light scattering, has high light transmission efficiency, and the light yield is significantly better than that of ultraviolet-visible inorganic scintillators; (2) Energy resolution: Chromium ion doped near-infrared scintillator crystals have fewer internal defects and excellent light emission uniformity, while ultraviolet-visible inorganic scintillators are prone to signal ambiguity due to particle interface scattering; (3) Radiation resistance: The dense structure of chromium ion doped near-infrared scintillator crystals reduces the radiation damage rate and extends the lifespan.

[0024] 2. This invention selects an existing ultraviolet-visible inorganic scintillator as the matrix material, providing a lower crystal field strength for the doped chromium ions, thus enabling the chromium ions to... 4 T 2g Energy level position is lower than 2 E g Energy levels were increased to improve the transition probability between excited states and the ground state, resulting in a redshift in the emission spectrum and broadband emission. A single crystal was grown using the melt-pulling method to ultimately prepare a complete, crack-free chromium-doped near-infrared scintillation crystal suitable for high-energy-load applications. This chromium-doped near-infrared scintillation crystal exhibits excellent properties such as large size, high transparency, and good radiation resistance. Attached Figure Description

[0025] Figure 1 Gd3Sc of Embodiment 1 of the present invention 1.995 Cr 0.005 Ga3O 12 Example 2 Gd3Sc 1.99 Cr 0.01 Ga3O 12 Compared with Comparative Example 1, Gd3Sc2Ga3O 12 XRD pattern of polycrystalline material.

[0026] Figure 2 Figure (a) is the Gd3Sc 1.995 Cr 0.005 Ga3O 12 Figure (b) is the Gd3Sc 1.995 Cr 0.005 Ga3O 12 Figure (c) is the transmittance curve of the double-side polished sample.

[0027] Figure 3 Figure (a) is the Gd3Sc 1.995 Cr 0.005 Ga3O 12 Figure (b) is the X-ray excitation spectrum of the double-side polished sample.

[0028] Figure 4 Figure (a) is the Gd3Sc 1.995 Cr 0.005 Ga3O 12 Figure (b) is the real photo of the double-side polished sample. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0030] In view of the problem of high price of the prior art near-infrared scintillation crystal, the present application uses the prior art ultraviolet-visible light inorganic scintillator as raw material, realizes the purpose of near-infrared luminescence by means of chromium ion doping, and greatly reduces the raw material cost.

[0031] In view of the problem of the prior art single-doped Eu 2+ or single-doped Sm 2+ , the present application selects chromium ions to dope the prior art ultraviolet-visible light inorganic scintillator, solves the problems of low light yield and poor energy resolution, and overcomes the problem of self-absorption.

[0032] In view of the problem of cracking and reduced light output of the prior art double-doped crystal, the chromium ion doped near-infrared scintillation crystal of the present application has a compact and ordered structure, and overcomes the defects of double doping.

[0033] The technical solutions of the present application will be further studied by means of the following examples, and the specific research methods and results are shown as follows: Example 1 The application discloses a preparation method of a chromium ion doped near-infrared scintillation crystal, and the chromium ion doped near-infrared scintillation crystal has a molecular formula of Gd3Sc 1.995 Cr 0.005 Ga3O 12 , and comprises the following steps: S1, according to a stoichiometric ratio of a molecular formula Gd3Sc 1.995 Cr 0.005 Ga3O 12 , the gadolinium oxide, the gallium oxide, the scandium oxide and the chromium oxide are weighed and placed in a mortar for grinding for 1 h, and are fully mixed to obtain a powder raw material.

[0034] S2, the powder raw material is first placed in a quartz crucible, and then is placed in a muffle furnace for calcination at 1300 DEG C for 24 h to obtain a polycrystal material.

[0035] S3, the polycrystal material is placed in an iridium gold crucible, the iridium gold crucible is placed in a temperature field formed by a heat preservation material, after completion of furnace loading, a growth cavity is vacuumized, a mixed gas composed of argon and carbon dioxide is filled, the carbon dioxide functions to inhibit volatilization of the gallium oxide, the volume ratio of the argon to the carbon dioxide is 17:3, the polycrystal material is melted by using an induction coil to heat and raise the temperature, a melt is obtained, a seed crystal is lowered, and the seed crystal is placed on the surface of the melt for 25 min; after the power is stabilized, crystal pulling is started, the pulling rate is 1 mm / h, and the rotation speed is 10 rpm; after necking, shoulder forming, diameter-keeping growth and tailing, the crystal is grown to a predetermined length, then is pulled out, and then is cooled to room temperature; the cooling condition is that the temperature is first lowered to 1000 DEG C at a rate of 75 w / h, and then is lowered to room temperature at a rate of 150 w / h; the furnace is discharged, and a single crystal material is obtained.

[0036] After the single crystal material growth is completed, annealing is carried out in air, the temperature is kept at 1400 DEG C for 36 h to reduce the thermal stress of the single crystal material, and a chromium ion doped near-infrared scintillation crystal is obtained.

[0037] Example 2 The preparation method of the chromium ion doped near-infrared scintillation crystal is same as that of the preparation steps in Example 1, and the difference is that x in the chromium ion doped near-infrared scintillation crystal is 0.01, and the molecular formula is Gd3Sc 1.99 Cr 0.01 Ga3O 12 , and comprises the following steps: S1, according to a stoichiometric ratio of a molecular formula Gd3Sc 1.99 Cr 0.01 Ga3O 12 , the gadolinium oxide, the gallium oxide, the scandium oxide and the chromium oxide are weighed and placed in a mortar for grinding for 1 h, and are fully mixed to obtain a powder raw material.

[0038] S2, first put the powder raw material into a quartz crucible, then place it in a muffle furnace, calcine at 1300℃ for 24h, to obtain polycrystalline material.

[0039] S3, put the polycrystalline material into an iridium crucible, place the iridium crucible in a temperature field constructed by a heat preservation material, after completing the furnace loading, vacuumize the growth cavity, fill in a mixed gas composed of argon and carbon dioxide, the role of carbon dioxide is to inhibit the volatilization of gallium oxide, the volume ratio of argon to carbon dioxide is 17:3, use an induction coil to heat and melt the polycrystalline material to obtain a melt, lower the seed crystal, place it on the surface of the melt for 25min, after the power is stable, start pulling and crystallizing, the pulling rate is 1mm / h, the rotation speed is 10rpm, after necking, shoulder placement, isometric growth and tailing, the crystal grows to the predetermined length, then pull out, then cool to room temperature, the cooling condition is: first cool to 1000℃ at a rate of 75w / h, then cool to room temperature at a rate of 150w / h, take out the furnace, to obtain single crystal material.

[0040] After the single crystal material growth is completed, anneal in air at 1400℃ for 36h to reduce the thermal stress of the single crystal material, to obtain a chromium ion doped near-infrared scintillation crystal.

[0041] Example 3 The preparation method of the chromium ion doped near-infrared scintillation crystal is the same as that of Example 1, the difference is only that the mixing method of step S1 is replaced by mixer mixing, and step S2 is pressed before calcination, including the following steps: S1, according to the stoichiometric ratio of the molecular formula Gd3Sc 1.995 Cr 0.005 Ga3O 12 , weigh gadolinium oxide, gallium oxide, scandium oxide and chromium oxide, mix for 48h using a mixer, pat the mixer 7 times during mixing, mix thoroughly, to obtain a powder raw material.

[0042] S2, use a pressing machine to press the powder raw material into a round cake shape, first put the powder raw material into a quartz crucible, then place it in a muffle furnace, calcine at 1300℃ for 24h in the muffle furnace, to obtain polycrystalline material.

[0043] S3, the polycrystalline material is placed in an iridium crucible, the iridium crucible is placed in a temperature field constructed by a heat preservation material, after the completion of loading, the growth cavity is vacuumized, a mixed gas composed of argon and carbon dioxide is filled, the carbon dioxide functions to inhibit the volatilization of gallium oxide, the volume ratio of argon to carbon dioxide is 17:3, the polycrystalline material is melted by using an induction coil to heat and warm, a melt is obtained, a seed crystal is lowered, and the seed crystal is placed on the surface of the melt for 25 min, after the power is stabilized, the crystal is pulled and grown, the pulling rate is 1 mm / h, the rotating speed is 10 rpm, after necking, shoulder releasing, isometric growth and tailing, the crystal is grown to a predetermined length, then the crystal is pulled off, and then the temperature is lowered to room temperature, the temperature lowering condition is that the temperature is lowered to 1000℃ at a rate of 75 w / h, and then the temperature is lowered to room temperature at a rate of 150 w / h, the furnace is unloaded, and a single crystal material is obtained.

[0044] After the growth of the single crystal material is completed, annealing is performed in air, the temperature is kept at 1400℃ for 36 h, so as to reduce the thermal stress of the single crystal material, and a chromium ion doped near-infrared scintillation crystal is obtained.

[0045] Example 4 A preparation method of a chromium ion doped near-infrared scintillation crystal, x in the chromium ion doped near-infrared scintillation crystal is 0.1, the molecular formula is Gd3Sc 1.9 Cr 0.1 Ga3O 12 , comprising the following steps: S1, according to the stoichiometric ratio of the molecular formula Gd3Sc 1.9 Cr 0..1 Ga3O 12 , gadolinium oxide, gallium oxide, scandium oxide and chromium oxide are weighed, a mixer is used for mixing for 48 h, and a powder raw material is obtained.

[0046] S2, the powder raw material is first placed in a quartz crucible, and then placed in a muffle furnace, calcined at 1300℃ for 24 h, and a polycrystalline material is obtained.

[0047] S3, the polycrystalline material is placed in an iridium crucible, the iridium crucible is placed in a temperature field constructed by a heat preservation material, after the completion of loading, the growth cavity is vacuumized, a mixed gas composed of argon and carbon dioxide is filled, the carbon dioxide functions to inhibit the volatilization of gallium oxide, the volume ratio of argon to carbon dioxide is 17:3, the polycrystalline material is melted by using an induction coil to heat and warm, a melt is obtained, a seed crystal is lowered, and the seed crystal is placed on the surface of the melt for 25 min, after the power is stabilized, the crystal is pulled and grown, the pulling rate is 1 mm / h, the rotating speed is 10 rpm, after necking, shoulder releasing, isometric growth and tailing, the crystal is grown to a predetermined length, then the crystal is pulled off, and then the temperature is lowered to room temperature, the temperature lowering condition is that the temperature is lowered to 1000℃ at a rate of 75 w / h, and then the temperature is lowered to room temperature at a rate of 150 w / h, the furnace is unloaded, and a single crystal material is obtained.

[0048] After the single crystal material growth is completed, annealing is performed in air, and heat stress of the single crystal material is reduced by keeping the temperature at 1400 DEG C for 36 hours, so as to obtain the chromium ion doped near-infrared scintillation crystal.

[0049] Example 5 The preparation method of the chromium ion doped near-infrared scintillation crystal has the molecular formula Y3Al 4.98 Cr 0.02 O 12 , and comprises the following steps: S1, according to the stoichiometric ratio of the molecular formula Y3Al 4.98 Cr 0.02 O 12 , the yttrium oxide, the aluminum oxide and the chromium oxide are weighed, a mixer is used for mixing for 48 hours, and the powder raw material is obtained by fully mixing.

[0050] S2, the powder raw material is first placed in a quartz crucible, and then placed in a muffle furnace, calcination is performed at 1400 DEG C for 48 hours, and the polycrystalline material is obtained.

[0051] S3, the polycrystalline material is placed in an iridium gold crucible, the iridium gold crucible is placed in a temperature field formed by a heat preservation material, after the furnace is completed, the growth cavity is vacuumized, a mixed gas composed of argon and carbon dioxide is filled, the volume ratio of the argon to the carbon dioxide is 3:1, the polycrystalline material is melted by using an induction coil to heat and warm, the melt is obtained, the seed crystal is lowered, the seed crystal is placed on the surface of the melt for 20 minutes, the power is stabilized, the crystal is pulled and grown after the power is stabilized, the pulling rate is 1 mm / h, the rotation speed is 8 rpm, the crystal is grown through necking, shoulder placement, equal-diameter growth and tailing, the crystal is pulled out after the crystal is grown to the predetermined length, and then the temperature is lowered to room temperature, the temperature is lowered to 1000 DEG C at a rate of 75 w / h, and then the temperature is lowered to room temperature at a rate of 150 w / h, the furnace is discharged, and the single crystal material is obtained.

[0052] After the single crystal material growth is completed, annealing is performed in air, and heat stress of the single crystal material is reduced by keeping the temperature at 1400 DEG C for 36 hours, so as to obtain the chromium ion doped near-infrared scintillation crystal.

[0053] Example 6 The preparation method of the chromium ion doped near-infrared scintillation crystal has the molecular formula Y3Al 4.95 Cr 0.05 O 12 , and comprises the following steps: S1, according to the stoichiometric ratio of the molecular formula Y3Al 4.95 Cr 0.05 O 12 , the yttrium oxide, the aluminum oxide and the chromium oxide are weighed, a mixer is used for mixing for 48 hours, and the powder raw material is obtained by fully mixing.

[0054] S2, first put the powder raw material into a quartz crucible, then put it into a muffle furnace, calcine at 1500℃ for 36h, to obtain polycrystalline material.

[0055] S3, put the polycrystalline material into an iridium crucible, put the iridium crucible into a temperature field constructed by a heat preservation material, after completing loading, vacuumize the growth cavity, fill in a mixed gas composed of argon and carbon dioxide, the volume ratio of argon to carbon dioxide is 9:1, use an induction coil to heat and melt the polycrystalline material to obtain a melt, lower the seed crystal, place it on the surface of the melt for 30min, after the power is stable, start pulling and crystallizing, the pulling rate is 1mm / h, the rotation speed is 12rpm, after necking, shoulder releasing, isodiametric growth, and tailing, the crystal grows to a predetermined length, then pull out, then cool to room temperature, the cooling condition is: first cool to 1000℃ at a rate of 75w / h, then cool to room temperature at a rate of 150w / h, discharge, to obtain single crystal material.

[0056] After the single crystal material growth is completed, anneal in air at 1300℃ for 48h to reduce the thermal stress of the single crystal material, to obtain a chromium ion doped near-infrared scintillation crystal.

[0057] Comparative Example 1 The preparation method of the near-infrared scintillation crystal is the same as that of Example 2, the only difference is that no chromium element is doped, the molecular formula of the near-infrared scintillation crystal is Gd3Sc2Ga3O 12 , denoted as GSGG, comprising the following steps: S1, according to the stoichiometric ratio of the molecular formula Gd3Sc2Ga3O 12 , weigh gadolinium oxide, gallium oxide and scandium oxide, put them into a mortar and grind for 1h, mix thoroughly to obtain a powder raw material.

[0058] S2, first put the powder raw material into a quartz crucible, then put it into a muffle furnace, calcine at 1300℃ for 24h, to obtain polycrystalline material.

[0059] S3, put the polycrystalline material into an iridium crucible, put the iridium crucible into a temperature field constructed by a heat preservation material, after completing loading, vacuumize the growth cavity, fill in a mixed gas composed of argon and carbon dioxide, the role of carbon dioxide is to inhibit the volatilization of gallium oxide, the volume ratio of argon to carbon dioxide is 17:3, use an induction coil to heat and melt the polycrystalline material to obtain a melt, lower the seed crystal, place it on the surface of the melt for 25min, after the power is stable, start pulling and crystallizing, the pulling rate is 1mm / h, the rotation speed is 10rpm, after necking, shoulder releasing, isodiametric growth, and tailing, the crystal grows to a predetermined length, then pull out, then cool to room temperature, the cooling condition is: first cool to 1000℃ at a rate of 75w / h, then cool to room temperature at a rate of 150w / h, discharge, to obtain single crystal material.

[0060] After the single crystal material growth is completed, annealing is performed in air, and the single crystal material is kept at 1400 DEG C for 36h to reduce thermal stress of the single crystal material, so that the near-infrared scintillation crystal is obtained.

[0061] The chromium ion doped near-infrared scintillation crystals with scintillation performance in the near-infrared wave band are prepared in the embodiments 1-6 of the present application, and the chromium ion doped near-infrared scintillation crystals in the embodiments 1-3 are taken as examples for research, and the specific research methods and results are shown as follows: Performance test: 1. XRD test: The powder samples of the embodiments 1, 2 and the comparative example 1 are respectively subjected to XRD test, and the powder samples are polycrystalline materials of Gd3Sc 1.995 Cr 0.005 Ga3O 12 , Gd3Sc 1.99 Cr 0.01 Ga3O 12 and Gd3Sc2Ga3O 12 of the embodiment 1, the embodiment 2 and the comparative example 1, and the results are shown in Table 1. Figure 1 The peak position and the relative intensity of the polycrystalline materials of Gd3Sc 1.995 Cr 0.005 Ga3O 12 and Gd3Sc 1.99 Cr 0.01 Ga3O 12 of the embodiment 1 and the embodiment 2 match the polycrystalline material of Gd3Sc2Ga3O 12 of the comparative example 1, which indicates that the polycrystalline materials are pure phases.

[0062] All the diffraction peaks in the powder samples of the embodiment 1, the embodiment 2 and the comparative example 1 can be well indexed to the standard pattern (PDF #53-0278), which confirms the formation of pure phases after the chromium ions are doped in the powder samples of the embodiment 1 and the embodiment 2, and the XRD peaks of the embodiment 1 and the embodiment 2 slightly move to a higher diffraction angle, which is consistent with the decrease of the host lattice parameters, because the ionic radius of the chromium ion is smaller than that of Sc 3+ , and the chromium ion can provide a lower crystal field strength for the doping.

[0063] 2. Transmittance test: After the Gd3Sc 1.995 Cr 0.005 Ga3O 12 crystal sample of the embodiment 3 is polished on both sides, the sample is placed on a paper with a grid, and the transmittance of the Gd3Sc 1.995 Cr 0.005 Ga3O 12 crystal sample is observed, and the results are shown in Table 2. Figure 2Figure (a) shows the Gd3Sc from Example 3. 1.995 Cr 0.005 Ga3O 12 Transmittance curves of the crystal sample were measured in the range of 200 nm to 1000 nm, indicating that Gd3Sc 1.995 Cr 0.005 Ga3O 12 It is a crystal, and a single crystal, as shown in the results. Figure 2 Figure (b) in the middle.

[0064] Figure 2 Figure (b) shows that three absorption bands were observed at 280 nm, 450 nm, and 640 nm, respectively, which belong to the chromium ion's... 4 A2→ 4 T1( 4 P) 4 A2→ 4 T1( 4 F) and 4 A2→ 4 T2( 4 The F) transition confirmed the incorporation of chromium ions in Example 3. No Cr was detected in the spectrum. 4+ The absorption at >900nm confirms that the dopant is Cr. 3+ , but without Cr 4+ .

[0065] 3. X-ray excitation spectroscopy test: Using X-rays as the excitation source, the Gd3Sc of Example 3 was subjected to X-rays. 1.995 Cr 0.005 Ga3O 12 The X-ray excitation spectra of the crystal samples were tested and characterized, and the results are shown in [Figure number missing]. Figure 3 .

[0066] After X-ray excitation, Gd3Sc in Example 3 1.995 Cr 0.005 Ga3O 12 The light emitted by the crystal sample had a wavelength range of 650 nm to 950 nm, confirming the presence of Gd3Sc from Example 3. 1.995 Cr 0.005 Ga3O 12 The crystal sample emits near-infrared light when excited by X-rays.

[0067] Figure 4 The results show that the Gd3Sc in Example 3 1.995 Cr 0.005 Ga3O 12 The crystal sample has a dense and ordered structure.

[0068] The above merely describes several embodiments of the present application, and does not limit the present application in any form. Although the present application is disclosed with the preferred embodiments, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical contents without departing from the scope of the technical solutions of the present application, and the equivalent embodiments are equivalent to the equivalent embodiments, which are within the scope of the technical solutions.

Claims

1. A chromium ion-doped near-infrared scintillation crystal, characterized in that, The molecular formula of chromium ion-doped near-infrared scintillation crystal is: A3B 2-x Cr x C3O 12 And 0.005≤x≤0.1; where A is a rare earth element; B is selected from Al, Sc, Ga; and C is selected from Al, Ga, In.

2. The chromium ion-doped near-infrared scintillation crystal according to claim 1, characterized in that, Chromium ion-doped near-infrared scintillation crystals can emit broadband near-infrared light with wavelengths of 650 nm to 950 nm when excited.

3. The chromium ion-doped near-infrared scintillation crystal according to claim 2, characterized in that, The wavelength of the chromium ion-doped near-infrared scintillation crystal is matched with the detection wavelength of the APD detector.

4. A method for preparing a chromium ion-doped near-infrared scintillation crystal as described in claim 1, characterized in that, Includes the following steps: According to the molecular formula A3B 2-x Cr x C3O 12 Weigh oxides A, B, C, and chromium oxide according to their stoichiometric ratio, mix them evenly, and obtain powder raw materials; In an aerobic environment, the powder raw material is calcined to obtain polycrystalline material; Polycrystalline material is grown into single crystals using the melt pulling method to obtain single crystal material; The single crystal material was annealed in air to obtain a chromium ion-doped near-infrared scintillation crystal.

5. The method for preparing a chromium ion-doped near-infrared scintillation crystal according to claim 4, characterized in that, The calcination conditions are: calcination at 1300℃~1500℃ for 24h~48h.

6. The method for preparing a chromium ion-doped near-infrared scintillation crystal according to claim 4, characterized in that, The operation of the melt pulling method is as follows: the polycrystalline material is heated to melt, the seed crystal is lowered, and after the power is stabilized, the crystal is pulled up at a pulling rate of 1 mm / h. The process involves necking, shoulder formation, constant diameter growth, tailing, and extraction to obtain a single crystal material.

7. The method for preparing a chromium ion-doped near-infrared scintillation crystal according to claim 6, characterized in that, Seed crystal is <111> Oriented seed crystals.

8. The method for preparing a chromium ion-doped near-infrared scintillation crystal according to claim 6, characterized in that, The atmosphere for single crystal growth is a mixture of argon and carbon dioxide, with a volume ratio of argon to carbon dioxide of 3 to 9:

1.

9. The method for preparing a chromium ion-doped near-infrared scintillation crystal according to claim 4, characterized in that, The annealing conditions are: heating at 1300℃~1500℃ for 24h~48h.

10. The application of the chromium ion-doped near-infrared scintillation crystal of claim 1 in the preparation of scintillation materials.

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