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

Abstract

The invention belongs to the technical field of radiation measurement and scintillation materials, and particularly relates to an Eu-doped multi-halide scintillator and a preparation method and application thereof. The invention provides an Eu-doped multi-element halide scintillator with a chemical composition of ASr < 1-0.5 x > Ba < 1-0.5 x > Eu < x > I < 5-y > By and a preparation method of the Eu-doped multi-element halide scintillator in order to solve the problems that an existing halide scintillator is low in energy resolution and poor in ionizing radiation luminous intensity, and crystals prepared through a conventional crystal growth process are poor in quality and the like. The scintillator with the chemical composition has excellent energy resolution and light yield, and the preparation method combines measures of raw material solid-phase reaction pre-synthesis, quartz crucible carbon film plating, seed crystal oriented growth and the like, so that successful preparation of the high-quality transparent single crystal is realized. The scintillator provided by the invention can be widely applied to the field of radiation detection, such as full-energy-spectrum gamma ray detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of radiation measurement and scintillation materials, and in particular relates to a Eu-doped multinary halide scintillator and a preparation method and application thereof. Background Art

[0002] In the field of radiation detection, gamma rays, as the highest-energy and most penetrating form of radiation in the electromagnetic spectrum, have a direct impact on nuclear safety, nuclear medicine diagnostic accuracy, and other aspects of their detection technology. Energy resolution and light yield, core performance indicators for detectors, determine their ability to resolve radiation events, sensitivity, and reliability. While traditional scintillation materials (such as LaBr3(Ce)) are widely used, their energy resolution (typically <3% at 662keV) has become a bottleneck limiting their detection accuracy. Meanwhile, for scintillation crystals, achieving a photon yield exceeding 10^5 ph / MeV would significantly advance "atomic-level energy spectrum resolution." At this photon yield, single-photon energy resolution might be possible, ushering in the quantum era of radiation sensing.

[0003] During the growth process, traditional halide scintillator crystals inevitably introduce defects such as impurity atoms, halide ion vacancies, and lattice distortion. These defects create additional energy levels within the crystal, acting as traps for electron-hole pairs. Once an electron or hole is trapped by a defect, a non-radiative transition occurs, significantly reducing the luminescence efficiency of the scintillator crystal. Furthermore, the effects of different types and concentrations of defects on crystal performance are complex and diverse, further increasing the difficulty of optimizing crystal performance. Furthermore, the crystal's band structure significantly influences the rate and concentration of carrier migration within the crystal. Therefore, when halide scintillators detect radiation, the resulting scintillation light signal often exhibits significant fluctuations due to the complex internal physical processes. This makes it difficult to accurately distinguish between radiation sources of similar energy when precisely measuring the radiation energy, resulting in large measurement errors and failure to meet the requirements of precise energy spectrum analysis, severely hindering the advancement of related research.

[0004] Eu 2+ As an excellent luminescence center, it often has high light yield and energy resolution in halide scintillating crystals, such as SrI2:Eu, CsBa2I5:Eu, etc. Among them, the light yield of SrI2:Eu crystal is as high as 120,000 ph / MeV and the energy resolution is 2.6%; while the light yield of CsBa2I5:Eu crystal is as high as 662keV. 137 The light output of the Cs source is 102,000 ph / MeV. They have potential applications in nuclear physics experiments, non-destructive testing of chemical substances, nuclear medicine, and modern counter-terrorism detection technology.

[0005] However, with the2+ As dopants enter the lattice, the difference in ionic radius will introduce certain defects, and the non-radiative recombination caused by the defect state energy level in the band gap will reduce the exciton capture efficiency, resulting in the measured light yield and energy resolution being far lower than the theoretical value. 2+ The luminescence comes from its 5d-4f transition, and the structure of the crystal energy band will greatly affect its luminescence efficiency. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention provides a Eu-doped multinary halide scintillator and its preparation method and application. The purpose of the present invention is to improve the performance of the scintillator and provide an effective method for preparing high-quality scintillators.

[0007] The first aspect of the present invention is to provide a Eu-doped multinary halide scintillator, the chemical composition of which is ASr 1- 0.5x Ba 1-0.5x Eu x I 5-y B y ; Wherein, 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%; Among them, the doping amount x of Eu element is in the range of 0.04±0.006; Wherein, the B-site element is a halogen element other than I, and y≤2 (y may be 0); Among them, Sr 2+ with Ba 2+ Forms a solid solution as an integral part of the matrix lattice.

[0008] As a further optimization scheme for the Eu-doped multinary halide scintillator, the A-site element is the alkali metal elements K and Cs, and there are no other alkali metal impurity elements; the A-site element is further preferably the K element.

[0009] As a further optimization solution for the Eu-doped multinary halide scintillator, x is within the range of 0.04±0.005, for example, x=0.035, 0.04, 0.045, etc. are selected within this range; more preferably, x can be selected within the range of 0.04±0.001.

[0010] As a further optimization solution for the Eu-doped multinary halide scintillator, the B-site element is selected as Br, and / or the amount of the B-site element y=1.

[0011] A second aspect of the present invention is to provide a method for preparing a Eu-doped multinary halide scintillator, comprising the following steps: (1) weighing Al powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder according to the chemical element stoichiometric ratio of the Eu-doped multi-halide scintillator, mixing them as raw material powders, and heating them for solid phase reaction pre-synthesis; (2) Prepare a quartz crucible with a capillary at the end and a carbon film on the inner wall; (3) placing the seed crystal into the capillary of the carbon film quartz crucible so that the b axis of the seed crystal is parallel to the length direction of the quartz crucible, and then placing the raw materials pre-synthesized by the solid phase reaction in step (1) into the carbon film quartz crucible and vacuum welding and sealing; (4) Place the carbon film quartz crucible vertically at the center of the cross section of the crystal growth furnace chamber, connect the heat conducting component to the lower part of the quartz crucible, adjust the height of the quartz crucible so that the middle of the seed crystal is located at the maximum temperature gradient of the crystal growth furnace, heat the crystal growth furnace, partially melt the seed crystal and keep it warm until the melt is fully convective; (5) The carbon film quartz crucible is lowered relative to the furnace body, and the crystal grows directionally 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.

[0012] As a further optimization scheme for the preparation method of Eu-doped multinary halide scintillator, in step (1), the AI ​​powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder are all in an anhydrous state, and the purity is ≥99.99%.

[0013] As a further optimization scheme for the preparation method of Eu-doped multinary halide scintillator, in step (1), the temperature of solid phase reaction pre-synthesis is 600-700°C, and the holding time is 10-20 hours.

[0014] As a further optimization scheme for the preparation method of Eu-doped multinary halide scintillator, in step (2), an organic gas is introduced into a quartz crucible with a capillary tube and the vacuum degree is lower than 1×10 -5 Pa and a temperature of 1130-1180°C for 1-20 hours to form a carbon film with a thickness of 50-100 microns on the crucible wall to obtain a carbon film quartz crucible.

[0015] As a further optimization scheme for the preparation method of Eu-doped multinary halide scintillator, in step (2), the organic gas is selected from: alkanes, alkynes, and the gas flow rate is 0.1-1 mL / min.

[0016] As a further optimization scheme for the preparation method of Eu-doped multinary halide scintillator, in step (5), the carbon film quartz crucible is lowered relative to the furnace body at a speed of 0.1-0.5 mm / h; after the melt is completely crystallized, the temperature is lowered at a rate of 0.5-50°C / h.

[0017] A third aspect of the present invention provides the use of Eu-doped multinary halide scintillators 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 receives this visible light and generates an electrical signal. The photoelectric conversion device, which converts the optical signal into an electrical signal, can be a photodiode, a photomultiplier tube, or other device.

[0018] Beneficial effects (1) The present invention prepares a Eu-doped ultra-high gamma energy resolution multi-component halide scintillator by SrBa alloying strategy; through theoretical calculation and optical method (Appendix Figure 1 、 2 ) proved that the multi-element halide has orderly adjusted the band structure based on the original ternary alloy halide, successfully suppressed ionization quenching, and improved the carrier migration efficiency; (2) The specific crucible descent method proposed in the present invention successfully solved the current situation of the difficulty in growing the multi-component halide scintillator, successfully prepared high-quality transparent single crystals, and provided a solution for the subsequent preparation of other crystals with similar problems; (3) The Eu-doped ultra-high gamma energy resolution multinary halide scintillator provided by the present invention has the advantages of high ionizing radiation luminescence efficiency and high energy resolution, and can be used for the detection of gamma rays and other objects. It has important application prospects in the fields of medical imaging, security inspection, oil well exploration and industrial inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of theoretical calculation results of the energy band structure of KSr2I5, KSrBaI5, and KBa2I5; Figure 2 A comparison diagram of the luminescence mechanism based on scintillators with different Sr / Ba ratios; Figure 3 This is a physical picture of the halide scintillator prepared in Example 1-5; Figure 4 KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 Photoluminescence excitation and emission spectra of I5 scintillator single crystal; Figure 5 KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 6 KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035Gamma pulse height spectrum of I5 scintillator single crystal; Figure 7 KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Photoluminescence excitation and emission spectra of I5 scintillator single crystal; Figure 8 KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 9 KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal; Figure 10 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Photoluminescence excitation and emission spectra of I5 scintillator single crystal; Figure 11 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 12 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Gamma pulse height spectrum of I5 scintillator single crystal; Figure 13 The CsSr prepared in Example 4 0.98 Ba 0.98 Eu 0.04 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 14 The CsSr prepared in Example 4 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal; Figure 15 KSr prepared in Example 5 0.9775 Ba 0.9775 Eu 0.04 Photoluminescence excitation and emission spectra of I4Br scintillator single crystal; Figure 16 KSr prepared in Example 5 0.9775 Ba 0.9775 Eu 0.04Ionizing radiation luminescence spectrum of I4Br scintillator single crystal; Figure 17 KSr prepared in Example 5 0.9775 Ba 0.9775 Eu 0.04 Gamma pulse height spectrum of I4Br scintillator single crystal; Figure 18 KSr prepared in Comparative Example 1 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator; Figure 19 KBa prepared in Comparative Example 2 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator; 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; Figure 21 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 22 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 Gamma pulse height spectrum of I5 scintillator single crystal; 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; Figure 24 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 25 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Gamma pulse height spectrum of I5 scintillator single crystal; 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; Figure 27KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 28 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Gamma pulse height spectrum of I5 scintillator single crystal; 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; Figure 30 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; Figure 31 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Gamma pulse height spectrum of I5 scintillator single crystal; 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; Figure 33 KSr prepared in Comparative Example 7 0.97 Ba 0.97 Eu 0.06 Ionizing radiation luminescence spectrum of I5 scintillator single crystal; 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; 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; 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; Figure 37 This is a photo of the crystal blank grown in Comparative Example 10; Figure 38 This is a photo of the crystal blank grown in Comparative Example 11; Figure 39 This is a photo of the crystal blank grown in Comparative Example 12.

[0020] Figure 40 This is a performance comparison chart of energy resolution and light yield of different scintillator materials. DETAILED DESCRIPTION

[0021] The present invention is further described below through the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, rather than to limit the present invention.

[0022] First, the present invention provides a Eu-doped multi-halide scintillator, the chemical composition of which is ASr 1-0.5x Ba 1- 0.5x Eu x I 5-y B y .

[0023] Among them, 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, preferably x is in the range of 0.04±0.001; the B-site element is a halogen element other than I (the I element has been measured separately in the formula), and y≤2 (y can be 0), preferably, the B-site element is Br, y=1.

[0024] It should be noted that the present invention adjusts the scintillator band structure in an orderly manner through SrBa alloying, improves the carrier migration efficiency, and improves the exciton capture efficiency to varying degrees, thereby increasing the radiation recombination probability of the luminescent halide scintillator. The electron-hole pairs excited by the ionizing radiation migrate to the Eu 2+ Nearby, a 5d-4f transition occurs after relaxation, resulting in a single emission source and a stable wavelength, achieving varying degrees of improvement in the ionizing radiation luminescence intensity. Simultaneously, SrBa alloying increases the ionization density, reducing the effective diameter of free electrons, thereby reducing the probability of defects capturing free electrons and causing non-radiative transitions. This improves the scintillator's energy linearity and enhances gamma energy resolution.

[0025] It should also be noted that the "SrBa alloying" utilized in the present invention specifically refers to the formation of a uniform phase of Sr and Ba metal cations in any ratio within the matrix lattice, forming a continuous solid solution across the entire concentration range. Unlike conventional scintillator materials prepared using Sr and Ba, the doping of Sr and Ba elements in conventional solutions and the SrBa alloying in the present invention differ fundamentally in the crystal formation principle. Furthermore, the Sr and Ba elements in conventional solutions generally cannot form a single uniform phase in any ratio; essentially, they form only a localized solid solution or doping form.

[0026] It should also be noted that the introduction of the halide ion Br in the present invention can be understood as the solid solution of the anion, which plays a similar role to the "SrBa alloying" mentioned above. It can further adjust the band structure of the scintillator, improve the migration efficiency of the carriers, and improve the exciton capture efficiency to varying degrees, thereby increasing the radiative recombination probability of the luminescent halide scintillator.

[0027] Based on the performance requirements of the scintillator provided by the present invention, the doping amount x of the Eu element needs to be limited. If the value of x is too large, the Stokes shift of the crystal will become smaller, the self-absorption effect will be aggravated, and it may also cause concentration quenching, thereby reducing the luminous efficiency of the scintillator; if the value of x is too small, the radiation recombination efficiency of carriers and Eu ions will become lower, thereby reducing the luminous efficiency.

[0028] Based on the performance requirements of the scintillator provided by the present invention, the amount of other halogens needs to be limited. If the value of y is too large (for example, when y exceeds 3), the crystal band gap will become larger, which is not conducive to improving the carrier migration efficiency. In addition, if the value of y is too large (for example, when y exceeds 2), it will also make it difficult for the crystal to produce the target phase structure of the present invention during the crystallization process.

[0029] In some embodiments, the Eu-doped multinary halide scintillator may be in the form of 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.

[0030] In some embodiments, the lattice parameters a, b, and c of the Eu-doped multinary halide scintillator single crystal may 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.

[0031] In the present invention, a tungsten target X-ray tube is used as the excitation source and an Ocean Optics QEpro spectrometer is used as the detector to test the ionizing radiation luminescence of a Eu-doped ultra-high gamma energy resolution multinary halide scintillator; an ORTEC multi-channel energy spectrum detector is used to test the gamma pulse height spectrum of the Eu-doped ultra-high gamma energy resolution multinary halide scintillator.

[0032] In some embodiments, the Eu-doped multinary halide scintillator exhibits an energy resolution of ≤2.11%, preferably 1.75%, under 662 keV gamma-ray excitation; and a light yield of 112,000-147,600 ph / MeV. The energy resolution of the halide scintillator single crystal provided by the present invention surpasses the 2% energy resolution bottleneck of scintillators, achieving the best value among all currently known scintillators.

[0033] The following is an exemplary description of a method for preparing a Eu-doped multinary halide scintillator provided by the present invention, wherein the method comprises the following steps: (1) weighing Al powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder according to the chemical element stoichiometric ratio of the Eu-doped multi-halide scintillator, mixing them as raw material powders, and heating them for solid phase reaction pre-synthesis; (2) introducing an organic gas into a quartz crucible with a capillary and performing pyrolysis to form a carbon film on the crucible wall to obtain a carbon film quartz crucible; (3) placing the seed crystal oriented along the crystal axis b into the capillary of the carbon film quartz crucible so that the crystal growth direction is parallel to the radial direction of the capillary, and placing the raw material powder pre-synthesized by the solid phase reaction into the carbon film quartz crucible; (4) vertically placing a carbon film quartz crucible containing a seed crystal and a raw material powder pre-synthesized by solid phase reaction in the center of a crystal growth furnace, and connecting a heat conducting component to the lower part of the carbon film quartz crucible, adjusting the height of the carbon film quartz crucible so that the middle of the seed crystal is located at the maximum temperature gradient of the crystal growth furnace, and then heating the crystal growth furnace to melt the seed crystal at the maximum temperature gradient of the crystal growth furnace and keep it warm to allow sufficient convection of the melt; (5) The carbon film quartz crucible is lowered relative to the furnace body, and the crystal grows directionally along the b crystal axis at the solid-liquid interface of the seed crystal. During the descending process, the crystal gradually solidifies toward the tail end until the melt is completely crystallized, and the temperature is lowered to obtain the Eu-doped multi-halide scintillator.

[0034] In some embodiments, in step (1), the AI ​​powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder are all in anhydrous state, and the purity is ≥99.99%.

[0035] In some embodiments, in step (1), the temperature of the solid-phase reaction presynthesis can be 600-700°C, the holding time can be 10-20 hours, and the heating rate can be 1-10°C / h. By first subjecting the raw material powder to a solid-phase reaction, a complex quaternary alloy phase can be presynthesized. In addition, the melting points of the Al powder, SrI2 powder, BaI2 powder, and EuI2 powder are different, and the solid-phase reaction presynthesis can fully melt them, thereby preventing the precipitation of the second phase in the crystal.

[0036] In some embodiments, in step (2), the organic gas may include alkane or alkyne gas, and the gas flow rate may be 0.1-1 mL / min; the vacuum degree of the pyrolysis may be lower than 1×10 -5 Pa, the heating rate can be 20-100°C / hour, the temperature can be 1130-1180°C, and the holding time can be 1-20 hours; preferably, the thickness of the carbon film can be 50-100 microns.

[0037] By forming a carbon film on the quartz crucible, it is ensured that the liquid molten material does not directly contact the quartz wall to cause a reaction, and at the same time, it is ensured that a second crystallization point does not appear during the growth process due to reasons such as the roughness of the crucible surface.

[0038] In step (3), the present invention adopts a directional growth method of the seed crystal, artificially controlling the crystal axis of abnormal negative thermal expansion to be parallel to the crystal growth direction, thereby preventing the b-axis from becoming larger when the temperature is lowered, causing the crystal to squeeze the crucible.

[0039] In some embodiments, in step (4), the heat-conducting component may include a metal copper column and a water-cooling tube. Connecting the heat-conducting component to the lower portion of the carbon film quartz crucible can increase heat dissipation, reduce thermal stress inside the crystal, and prevent cracking during cooling.

[0040] In some embodiments, in step (5), the carbon film quartz crucible is preferably lowered relative to the furnace body at a speed of 0.1-0.5 mm / h, and the cooling rate is preferably 0.5-50°C / h. If the lowering speed is too high, it is easy to cause excessive stress inside the crystal and cracking; if the lowering speed is too low, the crystal growth cycle will be prolonged and the growth cost will increase.

[0041] The Eu-doped multinary halide scintillator provided by the present invention can be applied to full-energy spectrum gamma-ray detection, ranging from weak radiation detection to strong radiation detection, for example, in soil detection, homeland security, deep space exploration, nuclear power detection, medical imaging, security inspection, oil well exploration and industrial detection.

[0042] The following further examples are given to describe the present invention in detail. It should be understood that the following examples are only used to further illustrate the present invention and cannot be interpreted as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters of the following examples are only examples within a suitable range, and those skilled in the art can make selections within a suitable range through the description of the present invention, and are not limited to the specific numerical values ​​of the examples. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0043] Example 1 The Eu-doped multi-halide scintillator single crystal KSr provided in this embodiment 0.9825 Ba 0.9825 Eu 0.035 The preparation method of I5 comprises the following steps: (1) According to the chemical formula KSr 0.9825 Ba 0.9825 Eu 0.035 The chemical element stoichiometric ratio in I5 is as follows: high-purity raw materials KI, SrI2, BaI2, and EuI2 powders with a purity of 99.99% and a total mass of 5 g are weighed respectively; in a glove box filled with argon or nitrogen, the raw materials are mixed uniformly and placed in a crucible, and the temperature is raised to 650°C at a rate of 10°C / h and kept at this temperature for 10 hours to perform solid-phase reaction pre-synthesis; (2) The inner wall of the quartz crucible with capillary tube was ultrasonically cleaned with deionized water, acetone and alcohol for 30 minutes in sequence. The cleaned quartz crucible was placed in an oven, heated to 150℃, kept warm for 12 hours and then slowly cooled to room temperature at 50℃ / h. The cleaned and dried quartz crucible was placed in a coating machine. The furnace chamber was first vacuumed to less than 1×10 -2 Pa, and then fill with high-purity nitrogen or argon to 1 atmosphere. After three cycles of operation, when the vacuum degree is lower than 1×10 -5 Pa, the temperature of the furnace chamber reaches 1140°C at a heating rate of 100°C / hour, and is kept at this temperature for 20 hours. Methane gas is introduced into the furnace chamber at a flow rate of 0.5 ml / min. After pyrolysis of the gas, a carbon film with a thickness of about 75 microns is formed on the inner wall of the crucible, thereby obtaining a carbon film quartz crucible; (3) In a glove box filled with argon or nitrogen, slowly place the seed crystal with the b crystal axis direction determined into the capillary at the end of the quartz crucible coated with the 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, so that the b crystal axis with abnormal thermal expansion characteristics in the grown crystal is parallel to the crystal growth direction; then, grind the raw material after the solid phase reaction in step (1) and transfer it to the above-mentioned quartz crucible, evacuate the crucible and seal it with welding; move the sealed quartz crucible to a crucible stand and let it stand for 24 hours, and use an electric spark gun vacuum detector to test the sealing contact of the crucible; (4) Place the sealed quartz crucible vertically at the center of the cross section of the crystal growth furnace chamber, with the bottom of the crucible directly in contact with the copper lead (heat-conducting component) to enhance the heat dissipation at the bottom; adjust the height of the quartz crucible so that the middle of the seed crystal is located at the maximum temperature gradient in the furnace chamber, which is determined by pre-measurement; then heat the crystal growth furnace to form a gradient temperature field with high temperature at the top and low temperature at the bottom in the furnace chamber, and partially melt the seed crystal, and keep it warm for 24 hours to ensure sufficient convection of the melt for uniform mixing; (5) The quartz crucible is lowered relative to the furnace body at a speed of 0.3 mm / h. The crystal grows directionally along the b crystal axis at the solid-liquid interface of the seed crystal. During the descending process, it gradually solidifies toward the tail end until the melt is completely crystallized. After the growth is completed, it is cooled to room temperature at a rate of 10°C / h. The solidified halide scintillator crystal is taken out from the quartz crucible in a dry environment to obtain the Eu-doped multi-halide scintillator.

[0044] Example 2 The preparation method of Eu-doped multinary halide scintillator single crystal provided in this embodiment is similar to that in embodiment 1, the main difference is that: in step (1), according to KSr 0.98 Ba 0.98 Eu 0.04 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0045] Example 3 The preparation method of Eu-doped multinary halide scintillator single crystal provided in this embodiment is similar to that in embodiment 1, the main difference is that: in step (1), according to KSr 0.9775 Ba 0.9775 Eu 0.045 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0046] Example 4 The preparation method of Eu-doped multinary halide scintillator single crystal provided in this embodiment refers to that in embodiment 1, the main difference is that: in step (1), according to CsSr 0.98 Ba 0.98 Eu 0.04Weigh CsI, SrI2, BaI2 and EuI2 raw material powders in the stoichiometric ratio of the chemical elements in I5; in a glove box filled with argon or nitrogen, mix the raw materials evenly and place them in a crucible, raise the temperature to 700°C at a rate of 10°C / h and keep it for 10 hours to carry out solid phase reaction pre-synthesis.

[0047] Example 5 The preparation method of Eu-doped multinary halide scintillator single crystal provided in this embodiment is similar to that in embodiment 1, the main difference is that: in step (1), according to KSr 0.98 Ba 0.98 Eu 0.04 The raw material powders of KI, KBr, SrI2, BaI2 and EuI2 are weighed in the stoichiometric ratio of the chemical elements in I4Br; in a glove box filled with argon or nitrogen, the raw materials are mixed evenly and placed in a crucible, and the temperature is raised to 700°C at a rate of 10°C / h and kept at this temperature for 10 hours to carry out solid phase reaction pre-synthesis.

[0048] Comparative Example 1 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 1.96 Eu 0.04 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0049] Comparative Example 2 The preparation method of Eu-doped halide scintillator provided in this comparative example is based on Example 1, with the main difference being that: in step (1), according to KBa 1.96 Eu 0.04 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0050] Comparative Example 3 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.995 Ba 0.995 Eu 0.01 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0051] Comparative Example 4 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.99 Ba 0.99 Eu 0.02 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0052] Comparative Example 5 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.985 Ba 0.985 Eu 0.03 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0053] Comparative Example 6 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.975 Ba 0.975 Eu 0.05 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0054] Comparative Example 7 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.97 Ba 0.97 Eu 0.06 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0055] Comparative Example 8 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 1.666 Ba 0.294 Eu 0.04 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0056] Comparative Example 9 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the KSr 0.294 Ba 1.666 Eu 0.04 Weigh the raw material powder according to the stoichiometric ratio of chemical elements in I5.

[0057] Comparative Example 10 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to Example 1, with the main difference being that in step (1), the raw materials are uniformly mixed in a glove box filled with argon or nitrogen, and solid-phase synthesis is not performed, but the raw materials are directly transferred to the quartz crucible described in step (3).

[0058] Comparative Example 11 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to that of Example 1, with the main difference being that in step (3), directional growth of seed crystals is not used.

[0059] Comparative Example 12 The preparation method of the Eu-doped halide scintillator provided in this comparative example refers to that of Example 1, with the main difference being that a conventional quartz crucible is used instead of a carbon film quartz crucible.

[0060] Figure 1 Schematic diagram of the theoretical calculation results of the band structures of KSr2I5, KSrBaI5, and KBa2I5. As can be seen from the figure, the band gap of KSrBaI5 with SrBa solid solution is larger than that of KSr2I5 and KBa2I5 systems, indicating that the band structure can be improved by the SrBa solid solution strategy.

[0061] Figure 2 This figure compares the luminescence mechanisms of scintillators constructed with different Sr / Ba ratios. As can be seen from the figure, the Eu-doped multinary halide scintillator proposed in this invention has a higher thermal ionization energy than the ternary system, which can help suppress ionization quenching and improve the luminescence performance of the crystal.

[0062] Figure 3 This is a photo of the halide scintillator crystal prepared in Example 1-5. As can be seen from the photo, the halide scintillator crystal prepared in Example 1-5 has high optical quality, is transparent as a whole, and has no inclusions.

[0063] Figure 4 KSr prepared in Example 1 0.9825 Ba 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 excitation spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 443 nm. 2+ Narrowband emission.

[0064] Figure 5 KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal has a narrowband emission at 443 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0065] Figure 6 KSr prepared in Example 1 0.9825 Ba 0.9825 Eu 0.035 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr0.9825 Ba 0.9825 Eu 0.035 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 841.45, with a half-maximum width of 16.66 and an energy resolution of 1.98%.

[0066] Figure 7 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 spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 443 nm. 2+ Narrowband emission.

[0067] Figure 8 KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal has a narrowband emission at 443 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0068] Figure 9 KSr prepared in Example 2 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 797.38, with a half-maximum width of 13.95 and an energy resolution of 1.75%.

[0069] Figure 10 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Photoluminescence excitation and emission spectra of I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045The excitation spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 443 nm. 2+ Narrowband emission.

[0070] Figure 11 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045 I5 scintillator single crystal has a narrowband emission at 443 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0071] Figure 12 KSr prepared in Example 3 0.9775 Ba 0.9775 Eu 0.045 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.9775 Ba 0.9775 Eu 0.045 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 808.81, with a half-maximum width of 15.45 and an energy resolution of 1.91%.

[0072] Figure 13 The CsSr prepared in Example 4 0.98 Ba 0.98 Eu 0.04 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, CsSr 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal has a narrowband emission at 440 nanometers under X-ray radiation, and the emission peak has a tail near the long-wave direction.

[0073] Figure 14 The CsSr prepared in Example 4 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, CsSr 0.98 Ba 0.98 Eu 0.04 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 902.85, with a half-maximum width of 19.11 and an energy resolution of 2.11%.

[0074] Figure 15KSr prepared in Example 5 0.98 Ba 0.98 Eu 0.04 Photoluminescence excitation and emission spectra of I4Br scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 The excitation spectrum and emission spectrum of I4Br scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 437 nm. 2+ Narrowband emission.

[0075] Figure 16 KSr prepared in Example 5 0.98 Ba 0.98 Eu 0.04 Ionizing radiation luminescence spectrum of I4Br scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 The I4Br scintillator single crystal exhibits a narrowband emission at 437 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0076] Figure 17 KSr prepared in Example 5 0.98 Ba 0.98 Eu 0.04 Gamma pulse height spectrum of I4Br scintillator single crystal. As can be seen from the figure, KSr 0.98 Ba 0.98 Eu 0.04 I4Br scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 3181.12, with a half-maximum width of 59.81 and an energy resolution of 1.88%.

[0077] Figure 18 KSr prepared in Comparative Example 1 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator. As can be seen from the figure, KSr 1.96 Eu 0.04 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 902.85, with a half-maximum width of 21.76 and an energy resolution of 2.41%.

[0078] Figure 19 KBa prepared in Comparative Example 2 1.96 Eu 0.04 Gamma pulse height spectrum of I5 scintillator. As can be seen from the figure, KBa 1.96 Eu 0.04 I5 scintillator single crystal137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 796.30, with a half-maximum width of 18.95 and an energy resolution of 2.38%.

[0079] 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 spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 442 nm. 2+ Narrowband emission.

[0080] Figure 21 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.995 Ba 0.995 Eu 0.01 I5 scintillator single crystal has a narrowband emission at 442 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0081] Figure 22 KSr prepared in Comparative Example 3 0.995 Ba 0.995 Eu 0.01 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.995 Ba 0.995 Eu 0.01 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 505.49, with a half-maximum width of 16.59 and an energy resolution of 3.34%.

[0082] 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 spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 442 nm. 2+ Narrowband emission.

[0083] Figure 24 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.99 Ba 0.99 Eu 0.02 I5 scintillator single crystal has a narrowband emission at 442 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0084] Figure 25 KSr prepared in Comparative Example 4 0.99 Ba 0.99 Eu 0.02 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.99 Ba 0.99 Eu 0.02 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 568.48, with a half-maximum width of 16.65 and an energy resolution of 2.93%.

[0085] 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 spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 443 nm. 2+ Narrowband emission.

[0086] Figure 27 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Ionizing radiation luminescence spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.985 Ba 0.985 Eu 0.03 I5 scintillator single crystal has a narrowband emission at 443 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0087] Figure 28 KSr prepared in Comparative Example 5 0.985 Ba 0.985 Eu 0.03 Gamma pulse height spectrum of I5 scintillator single crystal. As can be seen from the figure, KSr 0.985 Ba0.985 Eu 0.03 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 684.65, with a half-maximum width of 16.41 and an energy resolution of 2.4%.

[0088] 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 spectrum and emission spectrum of I5 scintillator single crystal overlap, indicating that the crystal has self-absorption and there is a Eu at 443 nm. 2+ Narrowband emission.

[0089] Figure 30 KSr prepared in Comparative Example 6 0.975 Ba 0.975 Eu 0.05 Ionizing radiation luminescence 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 has a narrowband emission at 443 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0090] Figure 31 KSr prepared in Comparative Example 6 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 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 620.20, with a half-maximum width of 16.20 and an energy resolution of 2.58%.

[0091] 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. 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 Eu at 444 nm. 2+Narrowband emission.

[0092] Figure 33 KSr prepared in Comparative Example 7 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 narrowband emission at 444 nanometers under X-ray radiation, which is consistent with the emission spectrum of photoluminescence.

[0093] 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. As can be seen from the figure, KSr 0.97 Ba 0.97 Eu 0.06 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 572.07, with a half-height width of 18.53 and an energy resolution of 3.24%.

[0094] 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. As can be seen from the figure, KSr 1.666 Ba 0.294 Eu 0.04 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 2957.95, with a half-maximum width of 70.99 and an energy resolution of 2.40%.

[0095] 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. As can be seen from the figure, KSr 0.294 Ba 1.666 Eu 0.04 I5 scintillator single crystal 137 Under Cs source irradiation, the full energy peak of 662 keV is located at channel 2967.62, with a half-maximum width of 71.82 and an energy resolution of 2.42%.

[0096] Figure 37This is a photo of the crystal blank grown in Comparative Example 10. As can be seen from the figure, the entire crystal is turbid and severely cracked, making it difficult to obtain high-quality single crystals that can be used for performance evaluation.

[0097] Figure 38 This is a photo of the crystal blank grown in Comparative Example 11. As can be seen from the figure, the quartz crucible used for crystal growth is broken, and the entire crystal has deliquesced and deteriorated, making it unusable.

[0098] Figure 39 This is a photo of the crystal blank grown in Comparative Example 12. As can be seen from the figure, the quartz crucible used for crystal growth reacts severely with the raw materials, and the crystal cannot grow.

[0099] The chemical compositions and luminescence performance parameters of the halide scintillators prepared in Examples 1-4 and Comparative Examples 1-9 are shown in Table 1.

[0100] Table 1 Chemical composition and luminescence performance parameters of halide scintillators A comparison of the performance data of the Examples and Comparative Examples in Table 1 demonstrates that the Eu-doped multinary halide scintillator of the present invention achieves significantly superior performance to that of other systems by controlling the Eu doping amount x within the range of 0.04±0.006 and regulating the SrBa alloying to form a uniform, continuous solid solution with a ratio close to 1:1. Examples 1-3 all achieve energy resolutions below 2.0% (with a minimum of 1.75%) and stable light yields of 131,500-132,600 ph / MeV. These performances are significantly superior to the energy resolutions of 2.38%-2.41% and light yields of 91,000-97,000 ph / MeV achieved by Comparative Examples 1 and 2, which do not employ SrBa alloying.

[0101] The influence of Eu doping concentration x is particularly obvious. When x≤0.03, the performance decreases significantly, especially when x≤0.02, such as Comparative Examples 3 and 4, the light yield is significantly reduced to 84000-94500 ph / MeV, and the energy resolution deteriorates to 2.93%-3.34%; when x≥0.05, the performance also decreases significantly, such as Comparative Examples 6 and 7, the light yield drops to 95000-103100 ph / MeV, and the energy resolution increases to 2.58%-3.24%.

[0102] 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 is still significantly improved and the light yield is significantly reduced, 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 improving the performance of the Eu-doped multi-halide scintillator.

[0103] The Eu-doped multinary halide scintillator provided by this invention exhibits exceptional performance. As shown in Figure 40, it offers the lowest energy resolution and highest light yield among currently reported scintillating materials, achieving the highest performance values ​​in the nearly 100-year history of scintillator development. Compared to currently commercially available enhanced lanthanum bromide crystals, its energy resolution exceeds 2% for the first time, potentially bringing gamma-ray detection accuracy and depth to a new level.

[0104] The above embodiments are illustrative only and are intended to illustrate the technical concepts and features of the present invention so that those skilled in the art can understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A Eu-doped multinary halide scintillator, characterized in that: The chemical composition of the Eu-doped multi-halide scintillator is ASr 1-0.5x Ba 1-0.5x Eu x I 5-y B y ; Wherein, 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%; Among them, the doping amount x of Eu element is in the range of 0.04±0.006; Wherein, the B-position element is a halogen element other than I, and y≤2; Among them, Sr 2+ with Ba 2+ Forms a solid solution as an integral part of the matrix lattice.

2. The Eu-doped multinary halide scintillator according to claim 1, characterized in that: The A-site element is K.

3. The Eu-doped multinary halide scintillator according to claim 1, wherein: x is in the range of 0.04±0.

005.

4. The Eu-doped multinary halide scintillator according to claim 1, wherein: x is in the range of 0.04±0.

001.

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

6. The method for preparing a Eu-doped multinary halide scintillator according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) weighing Al powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder according to the chemical element stoichiometric ratio of the Eu-doped multi-halide scintillator, mixing them as raw material powders, and heating them for solid phase reaction pre-synthesis; (2) Prepare a quartz crucible with a capillary at the end and a carbon film on the inner wall; (3) placing the seed crystal into the capillary of the carbon film quartz crucible so that the b axis of the seed crystal is parallel to the length direction of the quartz crucible, and then placing the raw materials pre-synthesized by the solid phase reaction in step (1) into the carbon film quartz crucible and vacuum welding and sealing; (4) Place the carbon film quartz crucible vertically at the center of the cross section of the crystal growth furnace chamber, connect the heat conducting component to the lower part of the quartz crucible, adjust the height of the quartz crucible so that the middle of the seed crystal is located at the maximum temperature gradient of the crystal growth furnace, heat the crystal growth furnace, partially melt the seed crystal and keep it warm until the melt is fully convective; (5) The carbon film quartz crucible is lowered relative to the furnace body, and the crystal grows directionally 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 a Eu-doped multinary halide scintillator according to claim 6, wherein: In step (1), the AI ​​powder, AB powder, SrI2 powder, BaI2 powder and EuI2 powder are all in an anhydrous state, and the purity is ≥99.99%; the temperature of the solid phase reaction pre-synthesis is 600-700°C, and the holding time is 10-20 hours.

8. The method for preparing a Eu-doped multinary halide scintillator according to claim 6, wherein: In step (2), an organic gas is introduced into a quartz crucible with a capillary tube and the vacuum is lower than 1×10 -5 Pa, pyrolysis at 1130-1180 ° C for 1-20 hours to form a carbon film with a thickness of 50-100 microns on the crucible wall to obtain a carbon film quartz crucible; the organic gas is selected from: alkanes, alkynes, and the gas flow rate is 0.1-1 mL / min.

9. The method for preparing a Eu-doped multinary halide scintillator according to claim 6, wherein: In step (5), the carbon film quartz crucible is lowered relative to the furnace body at a speed of 0.1-0.5 mm / h; after the melt is completely crystallized, the temperature is lowered at a rate of 0.5-50°C / h.

10. Use of the Eu-doped multinary halide scintillator in radiation detection according to any one of claims 1 to 5, 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 generates an electrical signal after receiving the visible light.

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