Eu-doped multicomponent halide scintillator and preparation method and application thereof

Abstract

The application belongs to the technical field of radiation measurement and scintillation material, and particularly relates to a Eu-doped multi-element halide scintillator and a preparation method and application thereof. 1‑0.5x Ba 1‑0.5x Eu x I 5‑y B y of the Eu-doped multi-element halide scintillator and a preparation method thereof, the scintillator with the chemical composition has excellent energy resolution and light yield, and the preparation method combines raw material solid-phase reaction pre-synthesis, carbon film plating of a quartz crucible and seed crystal directional growth, and successfully realizes preparation of high-quality transparent single crystals. The scintillator provided by the application can be widely applied to the field of radiation detection, such as full-spectrum gamma ray detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radiation measurement and scintillation material, and particularly relates to a Eu-doped multi-element halide scintillator as well as a preparation method and application thereof. BACKGROUND

[0002] In the field of radiation detection, gamma rays, as the radiation form with the highest energy and the strongest penetration in the electromagnetic spectrum, its detection technology is directly related to nuclear energy safety, nuclear medical diagnosis accuracy and many other aspects. Energy resolution and light yield, as the core indicators to measure the performance of the detector, determine the ability of the detector to analyze radiation events, sensitivity and reliability. Although traditional scintillation materials (such as LaBr3(Ce) and the like) are widely used, their energy resolution (usually <3% @ 662 keV) has become a bottleneck restricting their detection accuracy. At the same time, for scintillation crystals, when the photon yield can break through 10^5 ph / MeV, it will strongly promote the "atomic level energy spectrum analysis", and in this case of photon yield, single-photon level energy analysis will be realized, which is conducive to opening up the quantum era of radiation perception.

[0003] The traditional halide scintillation crystal inevitably introduces impurity atoms, halogen ion vacancies, lattice distortions and other defects in the growth process. These defects will form additional energy levels in the crystal, becoming traps for electron-hole pairs. Once the electron or hole is captured by the defect, a non-radiative transition will occur, greatly reducing the light-emitting efficiency of the scintillator crystal. Moreover, the influence of different types and concentrations of defects on the performance of the crystal is complex and diverse, further increasing the difficulty of optimizing the performance of the crystal. At the same time, the energy band structure of the crystal will greatly affect the rate and concentration of carrier migration in the crystal. Therefore, when the halide scintillator detects radiation, due to the complex internal physical process, the generated scintillation light signal often has a large fluctuation. This leads to difficulty in accurately distinguishing radiation sources with similar energies when accurately measuring radiation energy, resulting in a large error in the measurement result, which cannot meet the demand of accurate energy spectrum analysis, and seriously hinders the further development of related research.

[0004] Eu 2+ As an excellent luminescent center, it often has high light yield and energy resolution in halide scintillation crystals, such as SrI2:Eu, CsBa2I5:Eu, etc. Among them, the light yield of SrI2:Eu crystal is as high as 120000 ph / MeV, and the energy resolution is 2.6%; while the light output of CsBa2I5:Eu crystal under 662 keV Cs source is 102000 ph / MeV. They have potential applications in nuclear physics experiments, non-destructive testing of chemical substances, nuclear medicine and modern anti-terrorism detection technology. 137 Cs source is 102000 ph / MeV. They have potential applications in nuclear physics experiments, non-destructive testing of chemical substances, nuclear medicine and modern anti-terrorism detection technology.

[0005] However, with the increasing demand for high-performance scintillation materials, the traditional Eu-doped halide scintillation crystals have gradually shown their limitations.2+ As a dopant into the lattice, the difference in ionic radius will introduce certain defects, and the non-radiative recombination caused by the defect state level in the band gap will reduce the exciton capture efficiency, resulting in that the measured light yield and energy resolution are much lower than the theoretical value. At the same time, the luminescence of Eu 2+ The luminescence of Eu comes from the transition of 5d-4f, and the structure of the crystal band will greatly affect the luminescence efficiency. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a Eu-doped multi-element halide scintillator and a preparation method and application thereof. The purpose of the present application is to improve the performance of the scintillator and to provide an effective method for preparing high-quality scintillators.

[0007] The first aspect of the present application is to provide a Eu-doped multi-element halide scintillator, which has a chemical composition of ASr 1- 0.5x Ba 1-0.5x Eu x I 5-y B y ;

[0008] Among them, the A-site element is an alkali metal element, selected from at least one of K and Cs, and the molar ratio of other alkali metal impurity elements to the A-site element is not more than 1%;

[0009] Among them, the doping amount x of Eu element is in the range of 0.04±0.006;

[0010] Among them, the B-site element is a halogen element other than I, and y≤2 (y can be 0);

[0011] Among them, Sr 2+ and Ba 2+ form a solid solution as a part of the matrix lattice.

[0012] As a further optimization scheme of the Eu-doped multi-element halide scintillator, the A-site element is an alkali metal element K and Cs, and there is no other alkali metal impurity element; the A-site element is further preferably K element.

[0013] As a further optimization scheme of the Eu-doped multi-element halide scintillator, x is in the range of 0.04±0.005, for example, x=0.035, 0.04, 0.045, etc. are selected in the range; more preferably, x can be selected in the range of 0.04±0.001.

[0014] As a further optimization scheme of the Eu-doped multi-element halide scintillator, the B-site element is selected as Br element, and / or the amount of B-site element y=1.

[0015] The second aspect of the present application provides a preparation method of the Eu-doped multi-element halide scintillator, comprising the following steps:

[0016] (1) According to the stoichiometric ratio of the chemical elements of the Eu-doped multi-element halide scintillator, AI powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder are weighed and mixed as raw material powder, and solid-phase reaction pre-synthesis is carried out by heating;

[0017] (2) A quartz crucible with a capillary tube at the end and a carbon film coated on the inner wall is prepared;

[0018] (3) The seed crystal is placed in the capillary tube of the carbon film quartz crucible, and the b crystal axis of the seed crystal is parallel to the length direction of the quartz crucible, and then the raw material pre-synthesized by solid-phase reaction in step (1) is placed in the carbon film quartz crucible, and vacuum welding is performed;

[0019] (4) The carbon film quartz crucible is vertically placed in the center of the cross section of the crystal growth furnace cavity, and a heat conduction component is connected to the lower part of the quartz crucible, the height of the quartz crucible is adjusted so that the middle part of the seed crystal is located at the position of the maximum temperature gradient of the crystal growth furnace, the crystal growth furnace is heated, and the seed crystal is partially melted and heat preserved until the melt is fully convected;

[0020] (5) The carbon film quartz crucible is lowered relative to the furnace body, and the crystal grows along the b crystal axis at the solid-liquid interface of the seed crystal, and then the melt is cooled after complete crystallization, and the Eu-doped multi-element halide scintillator is obtained.

[0021] As a further optimization scheme of the preparation method of the Eu-doped multi-element halide scintillator, in step (1), the AI powder, the AB powder, the SrI2 powder, the BaI2 powder and the EuI2 powder are all in anhydrous state, and the purity of each is ≥99.99%.

[0022] As a further optimization scheme of the preparation method of the Eu-doped multi-element halide scintillator, in step (1), the temperature for solid-phase reaction pre-synthesis is 600-700℃, and the heat preservation time is 10-20 hours.

[0023] As a further optimization scheme of the preparation method of the Eu-doped multi-element halide scintillator, in step (2), the carbon film quartz crucible is obtained by introducing an organic gas into the quartz crucible with a capillary tube and pyrolyzing at a temperature of 1130-1180℃ for 1-20 hours under a vacuum degree of less than 1×10 -5 Pa, to form a carbon film with a thickness of 50-100 microns on the crucible wall.

[0024] As a further optimization scheme of the preparation method of the Eu-doped multi-element halide scintillator, in step (2), the organic gas is selected from: alkanes, alkynes, and the gas flow is 0.1-1 mL / min.

[0025] As a further optimization scheme of the preparation method of the Eu-doped multinary halide scintillator, in step (5), the carbon film quartz crucible is lowered at a speed of 0.1-0.5 mm / h relative to the furnace body; after the melt is completely crystallized, the temperature is lowered at a rate of 0.5-50 ℃ / h.

[0026] The third aspect of the present application provides an application of the Eu-doped multinary halide scintillator in radiation detection. The scintillator can be coupled with a photoelectric conversion device to form a radiation detection element. The scintillator is excited by radiation to generate visible light, and the photoelectric conversion device generates an electrical signal after receiving the visible light. The photoelectric conversion device is used to convert the optical signal into an electrical signal, and devices such as photodiodes and photomultiplier tubes can be selected.

[0027] Advantages

[0028] (1) The present application prepares an Eu-doped multinary halide scintillator with ultra-high gamma energy resolution through SrBa alloying strategy; theoretical calculation and optical methods (attached Figure 1 , 2 ) prove that the multinary halide successfully suppresses ionization quenching and improves carrier mobility efficiency by orderly adjusting the energy band structure on the basis of the original ternary alloy halide;

[0029] (2) The specific crucible lowering method proposed in the present application successfully solves the current situation of difficult growth of the multinary halide scintillator, successfully prepares high-quality transparent single crystals, and provides a solution for other crystals with similar problems;

[0030] (3) The Eu-doped multinary halide scintillator with ultra-high gamma energy resolution provided by the present application has advantages such as high ionizing radiation luminescence efficiency and high energy resolution, and can be used for the detection of gamma rays, etc., and has important application prospects in the fields of medical imaging, security check, oil exploration and industrial detection. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of the theoretical calculation results of the energy band structure of KSr2I5, KSrBaI5 and KBa2I5;

[0032] Figure 2 is a comparison diagram of the luminescence mechanism based on different Sr / Ba ratios of the scintillator;

[0033] Figure 3 is a real object diagram of the halide scintillator prepared in Examples 1-5;

[0034] Figure 4 is a luminescence excitation and emission spectrum diagram of the KSr 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal prepared in Example 1;

[0035] Figure 5 KSrI5 scintillator single crystal prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal prepared in Example 1

[0036] Figure 6 KSrI5 scintillator single crystal prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal prepared in Example 1

[0037] Figure 7 KSrI5 scintillator single crystal prepared in Example 2 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal prepared in Example 2

[0038] Figure 8 KSrI5 scintillator single crystal prepared in Example 2 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal prepared in Example 2

[0039] Figure 9 KSrI5 scintillator single crystal prepared in Example 2 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal prepared in Example 2

[0040] Figure 10 KSrI5 scintillator single crystal prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 I5 scintillator single crystal prepared in Example 3

[0041] Figure 11 KSrI5 scintillator single crystal prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 I5 scintillator single crystal prepared in Example 3

[0042] Figure 12 KSrI5 scintillator single crystal prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 I5 scintillator single crystal prepared in Example 3

[0043] Figure 13 CsSrI5 scintillator single crystal prepared in Example 4 0.98 Ba 0.98 Eu 0.04Gamma pulse height spectrum of I5 scintillator single crystal;

[0044] Figure 14 CsSr 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal;

[0045] Figure 15 KSr 0.9775 Ba 0.9775 Eu 0.04 Photoluminescence excitation and emission spectra of I4Br scintillator single crystal;

[0046] Figure 16 KSr 0.9775 Ba 0.9775 Eu 0.04 Ionizing radiation luminescence spectrum of I4Br scintillator single crystal;

[0047] Figure 17 KSr 0.9775 Ba 0.9775 Eu 0.04 Gamma pulse height spectrum of I4Br scintillator single crystal;

[0048] Figure 18 KSr 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator;

[0049] Figure 19 KBa 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator;

[0050] Figure 20 KSr 0.995 Ba 0.995 Eu 0.01 Photoluminescence excitation and emission spectra of I5 scintillator single crystal;

[0051] Figure 21 KSr 0.995 Ba 0.995 Eu 0.01 Ionizing radiation luminescence spectrum of I5 scintillator single crystal;

[0052] Figure 22 KSr 0.995 Ba 0.995 Eu 0.01 Gamma pulse height spectrum of I5 scintillator single crystal;

[0053] Figure 23 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Photoluminescence excitation and emission spectra of I5 scintillator single crystal;

[0054] Figure 24 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Ionizing radiation luminescence spectra of I5 scintillator single crystal;

[0055] Figure 25 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Gamma pulse height spectra of I5 scintillator single crystal;

[0056] Figure 26 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Photoluminescence excitation and emission spectra of I5 scintillator single crystal;

[0057] Figure 27 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Ionizing radiation luminescence spectra of I5 scintillator single crystal;

[0058] Figure 28 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Gamma pulse height spectra of I5 scintillator single crystal;

[0059] Figure 29 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Photoluminescence excitation and emission spectra of I5 scintillator single crystal;

[0060] Figure 30 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Ionizing radiation luminescence spectra of I5 scintillator single crystal;

[0061] Figure 31 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05Gamma pulse height spectrum of I5 scintillator single crystal;

[0062] Figure 32 KSr prepared in Comparative Example 7 0.97 Ba 0.97 Eu 0.06 Photoluminescence excitation and emission spectra of I5 scintillator single crystal;

[0063] Figure 33 KSr prepared in Comparative Example 7 0.97 Ba 0.97 Eu 0.06 Ionizing radiation emission spectrum of I5 scintillator single crystal;

[0064] Figure 34 KSr prepared in Comparative Example 7 0.97 Ba 0.97 Eu 0.06 Gamma pulse height spectrum of I5 scintillator single crystal;

[0065] Figure 35 KSr prepared in Comparative Example 8 1.666 Ba 0.294 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal;

[0066] Figure 36 KSr prepared in Comparative Example 9 0.294 Ba 1.666 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal;

[0067] Figure 37 Photograph of the crystal blank grown in Comparative Example 10;

[0068] Figure 38 Photograph of the crystal blank grown in Comparative Example 11;

[0069] Figure 39 This is a photograph of the crystal blank grown in Comparative Example 12.

[0070] Figure 40 This is a comparison chart of the energy resolution and light yield of different scintillator materials. Detailed Implementation

[0071] The present invention will be further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0072] First, this invention provides an Eu-doped multi-component halide scintillator with the chemical composition ASr 1-0.5x Ba 1- 0.5x Eux I 5-y B y .

[0073] wherein the A-site element is an alkali metal element selected from at least one of K and Cs, and the A-site element is preferably K; the doping amount x of the Eu element is in the range of 0.04±0.006, and preferably x is in the range of 0.04±0.001; the B-site element is a halogen element other than I (I element is separately accounted for in the formula), and y≤2 (y can be 0), and preferably the B-site element is Br and y=1.

[0074] It should be noted that in the present application, the energy band structure of the scintillator is adjusted by SrBa alloying, the carrier migration efficiency is improved, the exciton capture efficiency is improved to different degrees, and thus the radiation recombination probability of the luminescent halide scintillator is improved. The electron-hole pairs excited by ionizing radiation migrate to the vicinity of Eu 2+ , relax, and then undergo 5d-4f transition, the emission source is single, the wavelength is stable, and the light intensity of ionizing radiation is improved to different degrees. Meanwhile, by SrBa alloying, the ionization density is increased, the effective diameter of the free electron is reduced, and thus the probability of non-radiative transition caused by defect capturing of the free electron is reduced, the energy linearity of the scintillator is improved, and the gamma energy resolution is improved.

[0075] It should be further noted that in the present application, the "SrBa alloying" specifically refers to that Sr and Ba two metal cations form a uniform phase in the matrix lattice at any ratio, and form a continuous solid solution in the whole concentration range. Unlike the scintillator material prepared by Sr and Ba two elements in the conventional technical solution, the doping of the Sr and Ba elements in the conventional technical solution is essentially different from the SrBa alloying in the present application in the principle of crystal formation. Further, the Sr and Ba elements in the conventional technical solution cannot generally form a single uniform phase at any ratio, and essentially only form a local solid solution or a doped form.

[0076] It should be further noted that in the present application, the introduction of the halogen ion Br can be understood as the solid solution of anions, which plays a similar role as the "SrBa alloying" above, can further adjust the energy band structure of the scintillator, improve the carrier migration efficiency, improve the exciton capture efficiency to different degrees, and thus improve the radiation recombination probability of the luminescent halide scintillator.

[0077] Based on the performance requirements of the scintillator provided in the present application, the doping amount x of the Eu element needs to be limited. If x is too large, the Stokes shift of the crystal becomes small, the self-absorption effect is intensified, and the concentration quenching may also occur, thereby reducing the light emission efficiency of the scintillator. If x is too small, the radiation recombination efficiency of the carrier and the Eu ion is low, thereby reducing the light emission efficiency.

[0078] The performance requirement of the scintillator provided in the present application limits the amount of other halogens. If y is too large (e.g., y is greater than 3), the band gap of the crystal becomes large, which is not conducive to improving the migration efficiency of the carriers. In addition, if y is too large (e.g., y is greater than 2), it is difficult to produce the target phase structure in the present application during the crystallization process.

[0079] In some embodiments, the Eu-doped multinary halide scintillator can be a bulk single crystal. Preferably, when the Eu-doped multinary halide scintillator is a bulk single crystal, the size of the Eu-doped multinary halide scintillator in at least one dimension is not less than 1 mm.

[0080] In some embodiments, the lattice parameters a, b, and c of the Eu-doped multinary halide scintillator single crystal can be in the range of 9.9 Å≤a≤10.3 Å, 8.9 Å≤b≤9.2 Å, and 14.2 Å≤c≤14.6 Å.

[0081] In the present application, a tungsten target X-ray tube is used as an excitation source and a QEpro spectrometer of ocean optics is used as a detector to test the ionizing radiation luminescence of the Eu-doped multinary halide scintillator with ultra-high gamma energy resolution. An ORTEC multi-channel energy spectrum detector is used to test the gamma pulse height spectrum of the Eu-doped multinary halide scintillator with ultra-high gamma energy resolution.

[0082] In some embodiments, the energy resolution of the Eu-doped multinary halide scintillator under the excitation of 662 keV gamma rays is ≤2.11%, preferably 1.75%. The light yield can be 112000-147600 ph. / MeV. The energy resolution of the halide scintillator single crystal provided in the present application can break through the bottleneck of 2% scintillator resolution, which is the best value among all known scintillators.

[0083] Hereinafter, the preparation method of the Eu-doped multinary halide scintillator provided in the present application is exemplarily described, which comprises the following steps:

[0084] (1) AI powder, AB powder, SrI2 powder, BaI2 powder, and EuI2 powder are weighed according to the stoichiometric ratio of the chemical elements of the Eu-doped multinary halide scintillator and mixed as raw material powder, and then solid-phase reaction pre-synthesis is performed by heating;

[0085] (2) An organic gas is introduced into a quartz crucible with a capillary tube and pyrolyzed to form a carbon film on the wall of the crucible, thereby obtaining a carbon film quartz crucible;

[0086] (3) Put the seed crystal oriented along the b crystal axis into the capillary of the carbon film quartz crucible to make the crystal growth direction parallel to the radial direction of the capillary, and put the raw material powder pre-synthesized by the solid phase reaction into the carbon film quartz crucible;

[0087] (4) Vertically place the carbon film quartz crucible containing the seed crystal and the raw material powder pre-synthesized by the solid phase reaction at the center position inside the crystal growth furnace, connect a heat conduction component at the lower part of the carbon film quartz crucible, adjust the height of the carbon film quartz crucible so that the middle position of the seed crystal is located at the position with the maximum temperature gradient of the crystal growth furnace, then heat the crystal growth furnace, melt the seed crystal at the position with the maximum temperature gradient of the crystal growth furnace, and keep the temperature to make the melt fully convect;

[0088] (5) Lower the carbon film quartz crucible relative to the furnace body, and the crystal grows along the b crystal axis at the solid-liquid interface of the seed crystal, and gradually solidifies to the tail end during the lowering process until the melt is completely crystallized, and then the temperature is lowered to obtain the Eu-doped multi-component halide scintillator.

[0089] In some embodiments, in step (1), the AI powder, the AB powder, the SrI2 powder, the BaI2 powder and the EuI2 powder are all in anhydrous state, and the purity of each is ≥ 99.99%.

[0090] In some embodiments, in step (1), the temperature for the solid phase reaction pre-synthesis can be 600-700℃, the holding time can be 10-20 hours, and the heating rate can be 1-10℃ / h. By first performing a solid phase reaction on the raw material powder, the pre-synthesis of the complex quaternary component alloy phase can be achieved. In addition, the melting points of the AI powder, the SrI2 powder, the BaI2 powder and the EuI2 powder are different, and the solid phase reaction pre-synthesis can make them fully melt to prevent the precipitation of the second phase in the crystal.

[0091] In some embodiments, in step (2), the organic gas can include alkane or alkyne gas, and the gas flow rate can be 0.1-1 mL / min; the pyrolysis vacuum degree can be lower than 1×10 -5 Pa, the heating rate can be 20-100℃ / h, the temperature can be 1130-1180℃, and the holding time can be 1-20 hours; preferably, the thickness of the carbon film can be 50-100 microns.

[0092] By forming a carbon film on the quartz crucible, it can be ensured that the liquid molten material does not directly contact the quartz wall to cause a reaction, and at the same time, it can be ensured that there is no second crystallization point due to the roughness of the crucible surface during the growth process.

[0093] In step (3), the present application adopts a seed crystal oriented growth method, artificially controls the crystal axis parallel to the crystal growth direction to avoid the b axis becoming larger during cooling to cause the crystal to extrude the crucible.

[0094] In some embodiments, in step (4), the heat-conducting component can include a copper column or a water-cooled tube. Connecting the heat-conducting component to the lower part of the carbon film quartz crucible can increase heat dissipation, reduce internal thermal stress of the crystal, and prevent cracking during temperature reduction.

[0095] In some embodiments, in step (5), the carbon film quartz crucible preferably descends at a speed of 0.1-0.5 mm / h, and the temperature preferably decreases at a rate of 0.5-50℃ / h. If the descending speed is too large, the internal stress of the crystal can be too large and the crystal can crack. If the descending speed is too small, the crystal growth period can be too long and the growth cost can increase.

[0096] The Eu-doped multi-element halide scintillator provided by the application can be applied in full-spectrum gamma ray detection, including weak radiation detection and strong radiation detection, such as soil detection, homeland security, deep space exploration, nuclear power detection, medical imaging, security inspection, oil exploration, and industrial detection.

[0097] The following examples are further provided to illustrate the application in detail. It should also be understood that the following examples are only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the application all belong to the protection scope of the application. The specific process parameters in the following examples are only one example in the appropriate range, i.e., those skilled in the art can select within the appropriate range through the description of the application, and are not limited to the specific values of the examples. If not specifically indicated, the technical means used in the examples are conventional means known to those skilled in the art.

[0098] Example 1

[0099] The Eu-doped multi-element halide scintillator single crystal KSr 0.9825 Ba 0.9825 Eu 0.035 The preparation method of the Eu-doped multi-element halide scintillator single crystal KSr

[0100] (1) The chemical elements in the Eu-doped multi-element halide scintillator single crystal KSr 0.9825 Ba 0.9825 Eu 0.035 I5 are weighed according to the chemical formula KSr

[0101] (2) The inner wall of the quartz crucible with capillary tube is ultrasonically cleaned for 30 minutes in sequence with deionized water, acetone and alcohol. The cleaned quartz crucible is placed in an oven and heated to 150°C. After holding at this temperature for 12 hours, it is slowly cooled to room temperature at a rate of 50°C / h. The cleaned and dried quartz crucible is then placed in a coating machine. The furnace cavity is first evacuated to a vacuum level below 1×10⁻⁶. -2 Then, purge with high-purity nitrogen or argon to 1 atmosphere. Repeat this cycle three times until the vacuum level drops below 1 × 10⁻⁶. -5 At Pa, the temperature of the furnace cavity is increased to 1140℃ at a heating rate of 100℃ / hour and held for 20 hours. Methane gas is introduced into the furnace cavity at a flow rate of 0.5 ml / min. After the gas is pyrolyzed, a carbon film of about 75 micrometers thick is formed on the inner wall of the crucible, resulting in a carbon film quartz crucible.

[0102] (3) In a glove box filled with argon or nitrogen, the seed crystal with the determined b-crystal axis direction is slowly placed into the capillary at the end of the quartz crucible coated with carbon film in step (2), so that the b-crystal axis of the seed crystal is parallel to the length direction of the quartz crucible. This makes the b-crystal axis with anomalous thermal expansion characteristics in the grown crystal parallel to the crystal growth direction. Then, the raw material that has completed the solid-phase reaction in step (1) is ground and transferred to the above-mentioned quartz crucible. The crucible is evacuated and sealed. The sealed quartz crucible is moved to the crucible rack and left to stand for 24 hours. The sealing contact of the crucible is tested by an electric spark gun vacuum detector.

[0103] (4) Place the sealed quartz crucible vertically at the center of the cross-section inside the crystal growth furnace cavity, with the bottom of the crucible in direct contact with the copper lead-down column (heat-conducting component) to enhance heat dissipation from the bottom; adjust the height of the quartz crucible so that the middle of the seed crystal is located at the point of maximum temperature gradient inside the furnace cavity, which is determined by pre-measurement; then heat the crystal growth furnace to create a gradient temperature field with a higher temperature at the top and a lower temperature at the bottom inside the furnace cavity, and partially melt the seed crystal, and hold it at that temperature for 24 hours to ensure that the melt is fully convectioned and mixed evenly;

[0104] (5) The quartz crucible is lowered relative to the furnace body at a speed of 0.3 mm / h. The crystal grows oriented along the b-crystal axis at the solid-liquid interface of the seed crystal. During the descent, it gradually solidifies towards the tail end until the melt is completely crystallized. After the growth is completed, it is lowered to room temperature at a rate of 10℃ / h. The solidified halide scintillator crystal is taken out from the quartz crucible in a dry environment to obtain the Eu-doped multi-component halide scintillator.

[0105] Example 2

[0106] The method for preparing Eu-doped multi-component halide scintillator single crystals provided in this embodiment is the same as in Example 1, the main difference being: in step (1), according to KSr 0.98 Ba 0.98 Eu0.04 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0107] Example 3

[0108] The preparation method of the Eu-doped multi-element halide scintillator single crystal provided in this example refers to Example 1, and the main difference lies in that in step (1), according to Ks 0.9775 Ba 0.9775 Eu 0.045 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0109] Example 4

[0110] The preparation method of the Eu-doped multi-element halide scintillator single crystal provided in this example refers to Example 1, and the main difference lies in that in step (1), according to CsSr 0.98 Ba 0.98 Eu 0.04 The raw material powders of CsI, SrI2, BaI2 and EuI2 are weighed according to the stoichiometric ratio of the chemical elements in I5; in an argon or nitrogen filled glove box, the raw materials are mixed uniformly and placed in a crucible, the temperature is increased to 700℃ at a rate of 10℃ / h, and the solid phase reaction is pre-synthesized for 10 hours.

[0111] Example 5

[0112] The preparation method of the Eu-doped multi-element halide scintillator single crystal provided in this example refers to Example 1, and the main difference lies in that in step (1), according to Ks 0.98 Ba 0.98 Eu 0.04 The raw material powders of KI, KBr, SrI2, BaI2 and EuI2 are weighed according to the stoichiometric ratio of the chemical elements in I4Br; in an argon or nitrogen filled glove box, the raw materials are mixed uniformly and placed in a crucible, the temperature is increased to 700℃ at a rate of 10℃ / h, and the solid phase reaction is pre-synthesized for 10 hours.

[0113] Comparative Example 1

[0114] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, and the main difference lies in that in step (1), according to Ks 1.96 Eu 0.04 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0115] Comparative Example 2

[0116] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, and the main difference lies in that in step (1), according to KBa 1.96 Eu 0.04The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0117] Comparative Example 3

[0118] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 0.995 Ba 0.995 Eu 0.01 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0119] Comparative Example 4

[0120] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 0.99 Ba 0.99 Eu 0.02 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0121] Comparative Example 5

[0122] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 0.985 Ba 0.985 Eu 0.03 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0123] Comparative Example 6

[0124] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 0.975 Ba 0.975 Eu 0.05 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0125] Comparative Example 7

[0126] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 0.97 Ba 0.97 Eu 0.06 The raw material powders are weighed according to the stoichiometric ratio of the chemical elements in I5.

[0127] Comparative Example 8

[0128] The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, the main difference being that in step (1), KSr 1.666 Ba 0.294 Eu 0.04The chemical element stoichiometric ratio in I5 is used to weigh the raw material powder.

[0129] Comparative Example 9

[0130] The preparation method of the Eu-doped halide scintillator provided in the present comparative example refers to Example 1, and the main difference is that in step (1), the raw materials are mixed uniformly in an argon or nitrogen filled glove box, and no solid phase synthesis is performed, but are directly transferred to the quartz crucible described in step (3). 0.294 Ba 1.666 Eu 0.04 The chemical element stoichiometric ratio in I5 is used to weigh the raw material powder.

[0131] Comparative Example 10

[0132] The preparation method of the Eu-doped halide scintillator provided in the present comparative example refers to Example 1, and the main difference is that in step (1), the raw materials are mixed uniformly in an argon or nitrogen filled glove box, and no solid phase synthesis is performed, but are directly transferred to the quartz crucible described in step (3).

[0133] Comparative Example 11

[0134] The preparation method of the Eu-doped halide scintillator provided in the present comparative example refers to Example 1, and the main difference is that in step (3), no seed crystal directional growth is used.

[0135] Comparative Example 12

[0136] The preparation method of the Eu-doped halide scintillator provided in the present comparative example refers to Example 1, and the main difference is that no carbon film quartz crucible is used, but a conventional quartz crucible is used.

[0137] Figure 1 It is a schematic diagram of the theoretical calculation results of the energy band structure of KSr2I5, KSrBaI5 and KBa2I5. As can be seen from the figure, the band gap of KSrBaI5 with SrBa solid solution is greater than that of KSr2I5 and KBa2I5 system, indicating that the energy band structure can be improved by SrBa solid solution strategy.

[0138] Figure 2 It is a comparison diagram of the luminescence mechanism based on different Sr / Ba ratios of the scintillator. As can be seen from the figure, the Eu-doped multinary halide scintillator proposed in the present application has a larger thermal ionization energy than the ternary system, which can promote the inhibition of ionization quenching and improve the luminescence performance of the crystal.

[0139] Figure 3 It is a crystal photograph of the halide scintillator prepared in Examples 1-5. As can be seen from the figure, the halide scintillator crystal prepared in Examples 1-5 has high optical quality and is transparent as a whole without inclusions.

[0140] Figure 4 It is a crystal photograph of the KSr 0.9825Ba 0.9825 Eu 0.035 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr... 0.9825 Ba 0.9825 Eu 0.035 The overlap between the excitation and emission spectra of the I5 scintillator single crystal indicates self-absorption in the crystal, and the presence of an Eu ion at 443 nm. 2+ Narrowband transmission.

[0141] Figure 5 The KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 The ionizing radiation emission spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystals exhibit a narrow-band emission at 443 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0142] Figure 6 The KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 The gamma pulse height spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 841.45, with a full width at half maximum (FWHM) of 16.66 and an energy resolution of 1.98%.

[0143] Figure 7 The KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr... 0.98 Ba 0.98 Eu 0.04 The excitation and emission spectra of the I5 scintillator single crystal overlap, indicating self-absorption in the crystal, and the presence of an Eu ion at 443 nm. 2+ Narrowband transmission.

[0144] Figure 8 The KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 The ionizing radiation emission spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.98 Ba 0.98 Eu0.04 The I5 scintillator single crystal has a narrow band emission at 443 nm under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0145] Figure 9 KSr 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of the I5 scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 The I5 scintillator single crystal has a narrow band emission at 443 nm under X-ray radiation, which is consistent with the emission spectrum of photoluminescence. 137 The full energy peak of 662 keV under Cs source irradiation is located at 797.38 channels, with a half-height width of 13.95 and an energy resolution of 1.75%.

[0146] Figure 10 KSr 0.9775 Ba 0.9775 Eu 0.045 Photoluminescence excitation and emission spectrum of the I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045 The excitation spectrum and the emission spectrum of the I5 scintillator single crystal overlap, indicating that the crystal has self-absorption, and there is a narrow band emission of Eu 2+ at 443 nm.

[0147] Figure 11 KSr 0.9775 Ba 0.9775 Eu 0.045 Ionizing radiation luminescence spectrum of the I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045 The I5 scintillator single crystal has a narrow band emission at 443 nm under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0148] Figure 12 KSr 0.9775 Ba 0.9775 Eu 0.045 Gamma pulse height spectrum of the I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045 The I5 scintillator single crystal has a narrow band emission at 443 nm under X-ray radiation, which is consistent with the emission spectrum of photoluminescence. 137 The full energy peak of 662 keV under Cs source irradiation is located at 808.81 channels, with a half-height width of 15.45 and an energy resolution of 1.91%.

[0149] Figure 13 CsSr 0.98 Ba 0.98 Eu 0.04 The luminescence spectrum of the I5 scintillator single crystal under ionizing radiation. As can be seen from the figure, the CsSr 0.98 Ba 0.98 Eu 0.04 The I5 scintillator single crystal has a narrow band emission at 440 nanometers under X-ray radiation, and the emission peak has a tail in the long wave direction.

[0150] Figure 14 CsSr 0.98 Ba 0.98 Eu 0.04 The gamma pulse height spectrum of the I5 scintillator single crystal. As can be seen from the figure, the CsSr 0.98 Ba 0.98 Eu 0.04 The I5 scintillator single crystal has a narrow band emission at 440 nanometers under X-ray radiation, and the emission peak has a tail in the long wave direction. 137 The full energy peak of 662 keV under Cs source irradiation is located at 902.85 channels, the half-height width is 19.11, and the energy resolution is 2.11%.

[0151] Figure 15 KSr 0.98 Ba 0.98 Eu 0.04 The excitation and emission spectrum of the I4Br scintillator single crystal under photoexcitation. As can be seen from the figure, the KSr 0.98 Ba 0.98 Eu 0.04 The excitation spectrum and the emission spectrum of the I4Br scintillator single crystal overlap, indicating that the crystal has self-absorption, and there is a narrow band emission of Eu 2+ at 437 nanometers.

[0152] Figure 16 KSr 0.98 Ba 0.98 Eu 0.04 The luminescence spectrum of the I4Br scintillator single crystal under ionizing radiation. As can be seen from the figure, the KSr 0.98 Ba 0.98 Eu 0.04 The I4Br scintillator single crystal has a narrow band emission at 437 nanometers under X-ray radiation, and the emission spectrum is consistent with the photoexcitation emission spectrum.

[0153] Figure 17 KSr 0.98 Ba 0.98 Eu 0.04 The gamma pulse height spectrum of the I4Br scintillator single crystal. As can be seen from the figure, the KSr0.98 Ba 0.98 Eu 0.04 I4Br scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 3181.12, with a full width at half maximum (FWHM) of 59.81 and an energy resolution of 1.88%.

[0154] Figure 18 KSr prepared in Comparative Example 1 1.96 Eu 0.04 The gamma pulse height spectrum of the I5 scintillator can be seen from the figure. 1.96 Eu 0.04 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 902.85, with a full width at half maximum (FWHM) of 21.76 and an energy resolution of 2.41%.

[0155] Figure 19 KBa prepared in Comparative Example 2 1.96 Eu 0.04 The gamma pulse height spectrum of the I5 scintillator can be seen from the figure. 1.96 Eu 0.04 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 796.30, with a full width at half maximum (FWHM) of 18.95 and an energy resolution of 2.38%.

[0156] Figure 20 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr... 0.995 Ba 0.995 Eu 0.01 The excitation and emission spectra of the I5 scintillator single crystal overlap, indicating self-absorption in the crystal, and the presence of an Eu ion at 442 nm. 2+ Narrowband transmission.

[0157] Figure 21 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 The ionizing radiation emission spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.995 Ba 0.995 Eu 0.01 I5 scintillator single crystals exhibit a narrow-band emission at 442 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0158] Figure 22KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 The gamma pulse height spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.995 Ba 0.995 Eu 0.01 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 505.49, with a full width at half maximum (FWHM) of 16.59 and an energy resolution of 3.34%.

[0159] Figure 23 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr... 0.99 Ba 0.99 Eu 0.02 The excitation and emission spectra of the I5 scintillator single crystal overlap, indicating self-absorption in the crystal, and the presence of an Eu ion at 442 nm. 2+ Narrowband transmission.

[0160] Figure 24 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 The ionizing radiation emission spectrum of an I5 scintillator single crystal. The figure shows that KSr... 0.99 Ba 0.99 Eu 0.02 I5 scintillator single crystals exhibit a narrow-band emission at 442 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0161] Figure 25 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 The gamma pulse height spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.99 Ba 0.99 Eu 0.02 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 568.48, with a full width at half maximum (FWHM) of 16.65 and an energy resolution of 2.93%.

[0162] Figure 26 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr...0.985 Ba 0.985 Eu 0.03 The excitation and emission spectra of the I5 scintillator single crystal overlap, indicating self-absorption in the crystal, and the presence of an Eu ion at 443 nm. 2+ Narrowband transmission.

[0163] Figure 27 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 The ionizing radiation emission spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.985 Ba 0.985 Eu 0.03 I5 scintillator single crystals exhibit a narrow-band emission at 443 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0164] Figure 28 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 The gamma pulse height spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.985 Ba 0.985 Eu 0.03 I5 scintillator single crystal in 137 Under Cs source irradiation, the full-energy peak at 662 keV is located at channel 684.65, with a full width at half maximum (FWHM) of 16.41 and an energy resolution of 2.4%.

[0165] Figure 29 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr... 0.975 Ba 0.975 Eu 0.05 The excitation and emission spectra of the I5 scintillator single crystal overlap, indicating self-absorption in the crystal, and the presence of an Eu ion at 443 nm. 2+ Narrowband transmission.

[0166] Figure 30 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 The ionizing radiation emission spectrum of an I5 scintillator single crystal. As can be seen from the figure, KSr... 0.975 Ba 0.975 Eu 0.05 I5 scintillator single crystals exhibit a narrow-band emission at 443 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0167] Figure 31 KSr 0.975 Ba 0.975 Eu 0.05 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.975 Ba 0.975 Eu 0.05 I5 scintillator single crystal under 137 Cs source irradiation, the full energy peak of 662 keV is located at 620.20 channels, the half-height width is 16.20, and the energy resolution is 2.58%.

[0168] Figure 32 KSr 0.97 Ba 0.97 Eu 0.06 Photoluminescence excitation and emission spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.97 Ba 0.97 Eu 0.06 The excitation spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption, and there is a narrow-band emission of Eu 2+ at 444 nm.

[0169] Figure 33 KSr 0.97 Ba 0.97 Eu 0.06 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.97 Ba 0.97 Eu 0.06 I5 scintillator single crystal has a narrow-band emission at 444 nm under X-ray irradiation, which is consistent with the emission spectrum of photoluminescence.

[0170] Figure 34 KSr 0.97 Ba 0.97 Eu 0.06 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.97 Ba 0.97 Eu 0.06 I5 scintillator single crystal under 137 Cs source irradiation, the full energy peak of 662 keV is located at 572.07 channels, the half-height width is 18.53, and the energy resolution is 3.24%.

[0171] Figure 35 KSr 1.666 Ba 0.294 Eu0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 1.666 Ba 0.294 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 137 Under Cs source irradiation, the full energy peak of 662 keV was located at 2957.95 channels, the half-height width was 70.99, and the energy resolution was 2.40%.

[0172] Figure 36 KSr 0.294 Ba 1.666 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.294 Ba 1.666 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 137 Under Cs source irradiation, the full energy peak of 662 keV was located at 2967.62 channels, the half-height width was 71.82, and the energy resolution was 2.42%.

[0173] Figure 37 Crystal blank grown in Comparative Example 10. As can be seen from the figure, the overall crystal appeared turbid, and was severely cracked, and it was difficult to obtain a single crystal of high quality that could be used for performance evaluation.

[0174] Figure 38 Crystal blank grown in Comparative Example 11. As can be seen from the figure, the quartz crucible in which the crystal was grown was broken, and the crystal was deliquescently deteriorated as a whole, and could not be used.

[0175] Figure 39 Crystal blank grown in Comparative Example 12. As can be seen from the figure, the quartz crucible in which the crystal was grown reacted severely with the raw material, and the crystal could not be grown.

[0176] The chemical composition and luminescent performance parameters of the halide scintillators prepared in Examples 1-4 and Comparative Examples 1-9 are shown in Table 1.

[0177] Table 1 Chemical composition and luminescent performance parameters of halide scintillators

[0178]

[0179] From the performance data of the examples and comparative examples in Table 1, it can be seen that in the Eu-doped multi-halide scintillator of the present application, the Eu element is controlled at a doping amount x in the range of 0.04±0.006, the SrBa alloying is adjusted to form a uniform continuous solid solution with a proportion close to 1:1, and the performance can be significantly better than other systems. The energy resolution of Examples 1-3 is less than 2.0% (as low as 1.75%), and the light yield is stable at 131500-132600 ph / MeV, which is much better than the energy resolution of 2.38%-2.41% and the light yield of 91000-97000 ph / MeV of Comparative Examples 1 and 2 which do not use SrBa alloying.

[0180] The effect of Eu doping concentration x is particularly obvious. When x≤0.03, the performance decreases significantly, especially when x≤0.02, as in Comparative Examples 3 and 4, the light yield decreases significantly to 84000-94500 ph / MeV, and the energy resolution deteriorates to 2.93%-3.34%; when x≥0.05, the performance also decreases significantly, as in Comparative Examples 6 and 7, the light yield decreases to 95000-103100 ph / MeV, and the energy resolution increases to 2.58%-3.24%.

[0181] As shown in Comparative Examples 8 and 9, when the ratio of Sr to Ba deviates from 1:1, even if the Eu doping amount x=0.04, the energy resolution still increases significantly, and the light yield decreases significantly, indicating that the alloying of SrBa in a molar ratio of 1:1 to form a uniform single-phase solid solution plays an important role in the performance improvement of the Eu-doped multi-halide scintillator.

[0182] The Eu-doped multi-halide scintillator provided by the present application exhibits excellent performance. As shown in FIG. 40, among the currently reported scintillating materials, it has the lowest energy resolution and the highest light yield, which is the optimal value in the performance of scintillators in the past hundred years. Compared with the currently commercialized enhanced lanthanum bromide crystal, the energy resolution has broken through 2% for the first time, which can improve the accuracy and depth of gamma detection to a new level.

[0183] The above examples are exemplary, and the purpose is to illustrate the technical concept and characteristics of the present application, so that those skilled in the art can understand the content of the present application and implement it, and the protection scope of the present application cannot be limited thereto. Any equivalent changes or modifications made in accordance with the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. An Eu-doped multi-component halide scintillator, characterized in that: The chemical composition of the Eu-doped multi-halogen scintillator is ASr 1-0.5x Ba 1-0.5x Eu x I 5-y B y ; Among them, the A-site element is an alkali metal element selected from at least one of K and Cs, and the molar ratio of other alkali metal impurity elements to the A-site element does not exceed 1%; The doping amount of Eu element, x, is in the range of 0.04 ± 0.006; Among them, the element at position B is a halogen element other than I, and y≤2; Among them, Sr 2+ with Ba 2+ It forms a solid solution as part of the matrix lattice.

2. The Eu-doped multi-component halide scintillator according to claim 1, characterized in that: The element at position A is K.

3. The Eu-doped multi-component halide scintillator according to claim 1, characterized in that: x is in the range of 0.04 ± 0.

005.

4. The Eu-doped multi-component halide scintillator according to claim 1, characterized in that: x is in the range of 0.04 ± 0.

001.

5. The Eu-doped multi-component halide scintillator according to claim 1, characterized in that: The element at position B is Br, and / or y=1.

6. The method for preparing an Eu-doped multi-component halide scintillator according to any one of claims 1 to 5, characterized in that: Includes the following steps: (1) Weigh AI powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder according to the stoichiometric ratio of the Eu-doped multi-halide scintillator and mix them as raw material powders, and heat them to carry out solid-phase reaction pre-synthesis. (2) Prepare a quartz crucible with a capillary tube at the end and a carbon film on the inner wall; (3) Place the seed crystal into the capillary of the carbon film quartz crucible, so that the b crystal axis of the seed crystal is parallel to the length direction of the quartz crucible, and then place the raw material pre-synthesized by solid-phase reaction in step (1) into the carbon film quartz crucible and vacuum seal it. (4) Place the carbon film quartz crucible vertically in the center of the cross-section of the crystal growth furnace cavity, and connect the heat-conducting component to the lower part of the quartz crucible. Adjust the height of the quartz crucible so that the middle part of the seed crystal is located at the maximum temperature gradient of the crystal growth furnace. Heat the crystal growth furnace to melt the seed crystal and keep it warm until the melt is fully convection. (5) The carbon film quartz crucible is lowered relative to the furnace body, and the crystal grows oriented along the b crystal axis at the solid-liquid interface of the seed crystal. After the melt is completely crystallized, the temperature is lowered to obtain the Eu-doped multi-halide scintillator.

7. The method for preparing an Eu-doped multi-component halide scintillator according to claim 6, characterized in that: In step (1), the AI ​​powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder are all in anhydrous state and have a purity of ≥99.99%; the temperature for solid-phase reaction pre-synthesis is 600-700℃ and the holding time is 10-20 hours.

8. The method for preparing an Eu-doped multi-component halide scintillator according to claim 6, characterized in that: In step (2), an organic gas is introduced into a quartz crucible with a capillary tube while maintaining a vacuum level below 1 × 10⁻⁶. -5 Pyrolysis at Pa and temperature of 1130-1180℃ for 1-20 hours forms a carbon film with a thickness of 50-100 micrometers on the crucible wall, resulting in a carbon film quartz crucible; the organic gas is selected from alkanes and alkynes, and the gas flow rate is 0.1-1 mL / min.

9. The method for preparing an Eu-doped multi-component halide scintillator according to claim 6, characterized in that: In step (5), the carbon film quartz crucible descends relative to the furnace body at a rate of 0.1-0.5 mm / h; after the melt has completely crystallized, it is cooled at a rate of 0.5-50℃ / h.

10. The application of the Eu-doped multi-component halide scintillator according to any one of claims 1 to 5 in radiation detection, characterized in that: The scintillator is coupled with a photoelectric conversion device to form a radiation detection element. The scintillator is excited by radiation to generate visible light, and the photoelectric conversion device receives the visible light and generates an electrical signal.

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