A LiF for neutron / gamma discrimination + Doped halide scintillation crystals and methods of making same
By doping Li+ ions into CsCu2I3 single crystals, Cs1-xCu2I3:xLi scintillation crystals were prepared, which solved the problem of insufficient light output and energy resolution of pure CsCu2I3 single crystals under γ-rays, and achieved higher light output and a wider range of applications, especially in the field of neutron detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-08-03
- Publication Date
- 2026-03-31
AI Technical Summary
The existing pure CsCu2I3 single crystals do not have outstanding light output and energy resolution under gamma rays, which limits their application in the field of gamma ray detection.
One-dimensional perovskite structure metal halide scintillation crystals of Cs1-xCu2I3:xLi were prepared by doping with Li+ ions. The crystals were grown in a vacuum environment using CuI, CsI and LiI powders, which maintained the same luminescence range but significantly improved the luminescence intensity.
This improves the light output performance of scintillation crystals, expands their application range to the field of neutron detection, and meets the requirements of high-performance energy spectrum and imaging detectors.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of artificial scintillation crystal technology, and in particular to a Li-type crystal for neutron / gamma discrimination. + Doped metal halide scintillation crystals and their preparation methods. Background Technology
[0002] Scintillation crystals are functional crystalline materials that can convert the energy of X-rays, gamma rays, or other high-energy particles into visible or ultraviolet light, figuratively described as "eyes" that can see high-energy rays or particles. Scintillation crystals are closely related to people's lives, with broad application markets in fields such as security inspection, nuclear medicine imaging, geological exploration, industrial non-destructive testing, high-energy physics, and environmental monitoring. They are one of the mainstream crystals with significant economic benefits in the world's crystal materials field today. To date, the most common are intrigued scintillators, such as NaI:Tl and CsI:Tl. In contrast, intrinsic scintillators have advantages such as good luminescence uniformity and uniform crystal composition distribution. In recent years, highly efficient and sensitive intrinsic scintillators with self-trapped exciton luminescence have emerged. Due to their high exciton binding energy and strong electron-phonon coupling, they exhibit large Stokes shifts. Many promising Cu-based low-dimensional perovskite intrinsic scintillators with high luminescence quantum yields have been discovered. For example, Rb₂CuBr₃ and Rb₂CuCl₃ can be used as sensitive X-ray scintillators, especially Rb₂CuCl₃, which has a light yield of over 90,000 ph / MeV under X-ray irradiation, comparable to the best commercially available scintillators. However, due to… 87 The presence of natural radioactive background in Rb greatly limits the application of gamma-ray spectroscopy in scintillators. (The last part, "through Cs," appears to be incomplete and unrelated to the preceding sentence. It has been left as is.) + Replace Rb + Ions, low-dimensional halide perovskites can be used as universal scintillators to detect a wide energy range of radiation from soft X-rays to hard gamma rays. For example, zero-dimensional pure Cs3Cu2I5 single crystals, as sensitive X-ray and gamma-ray scintillators, have a high light yield of 32,000 photons / MeV and an energy resolution of 3.4% under 662 keV irradiation, and the afterglow drops to 0.03% of the initial value 10 ms after X-ray excitation.
[0003] CsCu₂I₃ single-crystal perovskite possesses advantages such as a high effective atomic number (Zeff = 50.6), low melting point (371℃), non-hygroscopicity, no self-absorption, ultra-low afterglow, and high scintillation yield. The density of CsCu₂I₃ crystals, measured using the Archimedes method, is approximately 5.01 g / cm³. 3 This corresponds to a relatively large X-ray absorption coefficient. The luminescence source of the one-dimensional perovskite structure CsCu₂I₃ crystal is localized in [Cu₂I₆]. 4-The CsCu₂I₃ crystal exhibits a polyhedral self-trapped exciton state with an emission peak at 570 nm. Due to its large Stokes shift (236 nm), CsCu₂I₃ does not exhibit self-absorption. Under X-ray excitation, it displays extremely low X-ray excitation afterglow (only 0.008% at 10 ms), four orders of magnitude lower than commercial CsI:Tl crystals. Under 137Cs γ-ray irradiation, its light output is 16,000 photons / MeV, with an energy resolution of 7.8% at 662 keV and a decay time of 97 ns. Increasing its thermal stability can improve its scintillation yield by one order of magnitude, far exceeding 100,000 photons / MeV. Pure CsCu₂I₃ single crystals show good overall performance under X-rays and have significant application potential. However, its light output and energy resolution under γ-rays are not outstanding, leaving considerable room for improvement. Therefore, it is necessary to find a dopant ion to enhance its scintillation performance and expand its application areas. Summary of the Invention
[0004] In view of the above technical background, the purpose of this invention is to provide a Li for neutron / gamma discrimination. + Doped one-dimensional perovskite-structured metal halide scintillation crystals and their preparation method. (Using Li...) + The incorporation of [a specific ingredient] not only improves the light output performance of the original pure crystal but also expands its application range to the field of neutron detection. To achieve the above and other related objectives, this invention first provides a Li [specific material]. + A doped one-dimensional perovskite-structured metal halide scintillation crystal, the chemical formula of which is Cs. 1-x Cu2I3:xLi, where the value of x is in the range of 0.001≤x≤0.1.
[0005] The Li + When excited by a 340nm light source, the emission wavelength of the doped one-dimensional perovskite structure metal halide scintillation crystal is between 350-550nm, which is not shifted compared to the pure crystal, but the emission peak intensity is greatly improved.
[0006] This invention also provides a method for preparing the one-dimensional perovskite structure metal halide scintillation crystal described herein, comprising: mixing CuI powder, CsI powder, and LiI powder in an inert atmosphere at a molar ratio of 2:(1-x):x, wherein 0.001≤x≤0.1, and using the mixture as raw material powder, filling it into a spontaneous nucleation quartz crucible, and vacuum sealing it; and growing the CsI-CsI-CsI-CsI-Li ... 1-x Cu2I3:xLi is a one-dimensional perovskite structure metal halide scintillation crystal.
[0007] Another aspect of the present invention provides the application of the one-dimensional perovskite structure metal halide scintillation crystal described herein in the fields of X-ray and neutron detection. Attached Figure Description
[0008] Figure 1 Examples 1-5 Li + Photograph of a doped one-dimensional perovskite structure metal halide scintillation crystal.
[0009] Figure 2 Example 1 Cs 0.95 X-ray diffraction pattern of Cu2I3:5%Li scintillation crystal.
[0010] Figure 3 Example 1 Cs 0.95 Cu2I3:5%Li scintillation crystal, Example 2 Cs 0.999 Cu2I3:0.1%Li scintillation crystal, Example 4 Cs 0.997 Cu2I5:3%Li scintillation crystal, Example 5 Cs 0.90 Fluorescence spectrum of Cu2I3:10%Li scintillation crystal.
[0011] Figure 4 Example 1 Cs 0.95 Decay time diagram of Cu2I5:5%Li scintillation crystal.
[0012] Figure 5 Example 1 Cs 2.85 Cu2I5:5%Li scintillation crystal, Example 3 Cs 2.99 Transmittance diagram of Cu2I5:1%Li scintillation crystal. Detailed Implementation
[0013] The present invention will be further described below with reference to the accompanying drawings and the following embodiments. It should be understood that the drawings and embodiments are for illustrative purposes only and are not intended to limit the present invention.
[0014] This invention studies Cs 1-x This invention utilizes a Cu2I3:xLi one-dimensional perovskite structure metal halide scintillation crystal to develop a novel scintillation crystal material that meets the requirements of high-performance energy dispersive spectroscopy and imaging detector applications. + The ability to enhance luminescence intensity without altering the excitation and emission range of the original pure component crystal, discovered during practical application, was used to prepare CsI powder, CuI powder, and LiI powder as raw materials. 1-x Cu₂I₃:xLi is a one-dimensional perovskite structure metal halide scintillation crystal, where x takes values ranging from 0.001. <x≤0.1。
[0015] Preparation method:
[0016] Raw material powder preparation: In an inert atmosphere glove box, CuI powder, CsI powder, and LiI powder are prepared in a molar ratio of 2:(1-x):x, where 0.001≤x≤0.1. After thorough mixing, this raw material powder is filled into a spontaneous nucleation quartz crucible and vacuum sealed. High-purity powders are preferred, for example, with a purity of 99.99% or higher, preferably 99.999% or higher.
[0017] Crystal growth: The crystal growth adopts the vertical Bridgman method (i.e., crucible lowering method), the growth atmosphere is a vacuum environment, the crystal growth rate is controlled at 0.2-1 mm / h, the temperature of the high temperature zone of the growth furnace is set at 490-550℃, and the gradient is 15-35℃ / mm.
[0018] The present invention is further illustrated by the following embodiments to better illustrate the invention. It should be understood that the following embodiments are only for further illustration of the invention and should not be construed as limiting the scope of protection of the invention. Any homogeneous adjustments and optimizations made by those skilled in the art based on the above description of the invention are within the scope of protection of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.
[0019] Example 1: Cs 0.95 Spontaneous nucleation crucible-descent growth of Cu2I3:5%Li scintillation crystals:
[0020] (1) In an inert atmosphere glove box, CuI, CsI and LiI powders with a purity of 99.99% were mixed in a stoichiometric ratio of CuI:CsI:LiI=2:0.95:0.05. 12.018g of CuI, 7.771g of CsI and 0.211g of LiI were weighed and mixed evenly.
[0021] (2) Fill the raw material powder into the quartz crucible, evacuate the crucible, and use an oxyhydrogen flame to melt the quartz column at the narrow wall protrusion at the crucible opening with the inner wall to achieve a sealing effect. Place it into the ceramic down-feed tube, then place the down-feed tube on the down-feed mechanism, and raise the bottom of the crucible to the upper edge of the temperature gradient zone in the furnace, and then start heating.
[0022] (3) Set the temperature of the high-temperature zone of the descending furnace to 470°C, heat the raw materials to a molten state, and keep them at that temperature for 30 hours;
[0023] (4) The quartz crucible is lowered at a speed of 0.4 mm / h via the lowering mechanism;
[0024] (5) After the crucible descends to the preset distance, slowly lower the temperature to room temperature, then remove it and transfer it to the glove box. Break the crucible to remove the crystal, and process it into a wafer sample by cutting, grinding and polishing. Take the remaining transparent scraps, grind them and process them into a powder sample.
[0025] The crystals obtained from the growth are of good quality (see Figure 1 The X-ray diffraction pattern of the powder sample matched very well with the standard PDF#45-0076 card for CsCu2I3, indicating good crystallinity (see [link]). Figure 2 Excitation by a 334 nm light source revealed self-trapped exciton luminescence with an emission center at 578 nm and a range of 400-800 nm. The emission intensity was significantly enhanced compared to the pure-component crystal (see [link to original text]). Figure 3 The attenuation time at room temperature during the 280nm monitoring wavelength is 69ns (see [reference]). Figure 4 This meets the needs of practical radiation detection applications. The wafer sample maintains good transmittance within the emission band, facilitating the reception of optical signals by the photon detector (see...). Figure 5 ).
[0026] Example 2: Cs 0.999 Spontaneous nucleation crucible descent growth of Cu2I3:0.1%Li scintillation crystals:
[0027] (1) In an inert atmosphere glove box, CuI, CsI and LiI powders with a purity of 99.99% were mixed in a stoichiometric ratio of CuI:CsI:LiI=2:0.999:0.001. 11.903g of CuI, 8.093g of CsI and 0.004g of LiI were weighed and mixed evenly.
[0028] (2) Fill the raw material powder into the self-nucleating quartz crucible, evacuate the crucible, and use an oxyhydrogen flame to make the quartz column located at the narrow wall protrusion of the crucible tube fused with the inner wall to achieve a sealing effect. Place it into the ceramic guide tube, then place the guide tube on the guide mechanism, and raise the bottom of the crucible to the upper edge of the temperature gradient zone in the furnace, and then start heating.
[0029] (3) Set the temperature of the high-temperature zone of the descending furnace to 490°C, heat the raw materials to a molten state, and keep them at that temperature for 30 hours;
[0030] (4) The quartz crucible is lowered at a speed of 1 mm / h by the lowering mechanism;
[0031] (5) After the crucible descends to the preset distance, slowly lower the temperature to room temperature, then remove it and transfer it to the glove box. Break the crucible to remove the crystal, and process it into a wafer sample by cutting, grinding and polishing. Take the remaining transparent scraps, grind them and process them into a powder sample.
[0032] The crystals obtained from the growth are of good quality (see Figure 1 The sample, excited by a 334 nm light source, exhibited self-trapped exciton luminescence with an emission center at 578 nm and a range of 400-800 nm (see [reference]). Figure 3 ).
[0033] Example 3: Cs 0.99 Spontaneous nucleation crucible-descent growth of Cu2I3:1%Li scintillation crystals:
[0034] (1) In an inert atmosphere glove box, CuI, CsI and LiI powders with a purity of 99.99% were mixed in a stoichiometric ratio of CuI:CsI:LiI=2:0.99:0.01. 11.924g of CuI, 8.034g of CsI and 0.042g of LiI were weighed and mixed evenly.
[0035] (2) Fill the raw material powder into the self-nucleating quartz crucible, evacuate the crucible, and use an oxyhydrogen flame to make the quartz column located at the narrow wall protrusion of the crucible tube fused with the inner wall to achieve a sealing effect. Place it into the ceramic guide tube, then place the guide tube on the guide mechanism, and raise the bottom of the crucible to the upper edge of the temperature gradient zone in the furnace, and then start heating.
[0036] (3) Set the temperature of the high-temperature zone of the descending furnace to 510°C, heat the raw materials to a molten state, and keep them at that temperature for 30 hours;
[0037] (4) The quartz crucible is lowered at a speed of 0.8 mm / h via the lowering mechanism;
[0038] (5) After the crucible descends to the preset distance, slowly lower the temperature to room temperature, then remove it and transfer it to the glove box. Break the crucible to remove the crystal, and process it into a wafer sample by cutting, grinding and polishing. Take the remaining transparent scraps, grind them and process them into a powder sample.
[0039] The crystals obtained from the growth are of good quality (see Figure 1 The sample, excited by a 334 nm light source, exhibited self-trapped exciton luminescence with an emission center at 578 nm and a range of 400-800 nm. Its emission intensity was significantly enhanced compared to the pure-component crystal (see [reference]). Figure 3 The wafer sample maintained good transmittance within the emission wavelength range, facilitating the reception of optical signals by the photon detector (see [reference]). Figure 5 )
[0040] Example 4: Cs 0.97 Spontaneous nucleation crucible-descent growth of Cu2I3:3%Li scintillation crystals:
[0041] (1) In an inert atmosphere glove box, CuI, CsI and LiI powders with a purity of 99.99% were mixed in a stoichiometric ratio of CuI:CsI:LiI=2:0.97:0.03. 11.971g of CuI, 7.903g of CsI and 0.126g of LiI were weighed and mixed evenly.
[0042] (2) Fill the raw material powder into the self-nucleating quartz crucible, evacuate the crucible, and use an oxyhydrogen flame to make the quartz column located at the narrow wall protrusion of the crucible tube fused with the inner wall to achieve a sealing effect. Place it into the ceramic guide tube, then place the guide tube on the guide mechanism, and raise the bottom of the crucible to the upper edge of the temperature gradient zone in the furnace, and then start heating.
[0043] (3) Set the temperature of the high-temperature zone of the lowering furnace to 530°C, heat the raw materials to a molten state, and hold for 30 hours;
[0044] (4) The quartz crucible is lowered at a speed of 0.6 mm / h via the lowering mechanism;
[0045] (5) After the crucible has descended to the preset distance, slowly lower the temperature to room temperature, and then take it out and transfer it to the glove box.
[0046] The crucible was broken to remove the crystal, which was then cut, ground, and polished to produce wafer samples. The remaining transparent scraps were then ground and processed into powder samples.
[0047] The crystals obtained from the growth are of good quality (see Figure 1 The sample, excited by a 334 nm light source, exhibited self-trapped exciton luminescence with an emission center at 578 nm and a range of 400-800 nm. Its emission intensity was significantly enhanced compared to the pure-component crystal (see [link to original text]). Figure 3 ).
[0048] Example 5: Cs 0.9 Spontaneous nucleation crucible-descent growth of Cu2I3:10%Li scintillation crystals:
[0049] (1) In an inert atmosphere glove box, CuI, CsI and LiI powders with a purity of 99.99% were mixed in a stoichiometric ratio of CuI:CsI:LiI=2:0.9:0.1. 12.139g of CuI, 7.436g of CsI and 0.426g of LiI were weighed and mixed evenly.
[0050] (2) Fill the raw material powder into the self-nucleating quartz crucible, evacuate the crucible, and use an oxyhydrogen flame to melt the quartz column located at the narrow wall protrusion of the crucible tube opening with the inner wall to achieve a sealing effect. Place it into the ceramic down-feed tube, then place the down-feed tube on the down-feed mechanism, and raise the bottom of the crucible to the upper edge of the temperature gradient zone in the furnace, and then start heating.
[0051] (3) Set the temperature of the high-temperature zone of the descending furnace to 550°C, heat the raw materials to a molten state, and keep them at that temperature for 30 hours;
[0052] (4) The quartz crucible is lowered at a speed of 0.2 mm / h via the lowering mechanism;
[0053] (5) After the crucible descends to the preset distance, slowly lower the temperature to room temperature, then remove it and transfer it to the glove box. Break the crucible to remove the crystal, and process it into a wafer sample by cutting, grinding and polishing. Take the remaining transparent scraps, grind them and process them into a powder sample.
[0054] The crystals obtained from the growth are of good quality (see Figure 1 When excited at a wavelength of 334 nm, the sample exhibited self-trapped exciton luminescence with the emission center at 578 nm and a range of 400-800 nm. Its emission intensity was significantly enhanced compared to the pure-component crystal (see [link]). Figure 3 ).
Claims
1. A Li + doped perovskite structure metal halide scintillation crystal having a chemical formula of Cs 1- x Cu2I3: xLi, characterized in that, The x value ranges from 0.001 to 0.
1. The crystal can distinguish neutrons and gamma rays under the irradiation of both neutrons and gamma rays.
2. The Li of claim 1, wherein the Li is a Li + A doped perovskite structure metal halide scintillation crystal, characterized in that, The crystal can emit wideband yellow light between 400-800 nm under the excitation of high-energy rays or high-energy particles.
3. The Li of any one of claims 1-2 + A method of preparing a doped perovskite metal halide scintillation crystal, comprising: CuI, CsI and LiI powders are mixed in a certain proportion under an inert atmosphere, filled into a self-nucleation quartz crucible, vacuum sealed, heated and melted, and then crystal growth is carried out to obtain the crystal.
4. The Li of claim 3 + A method for preparing a doped perovskite structure metal halide scintillation crystal, characterized by, CuI powder, CsI powder, and LiI powder are dosed in a molar ratio of 2:(1-x):x, and after being mixed thoroughly, the powders are used as raw material powders, wherein 0.001≤x≤0.1; and the Cs 1-x Cu2I3:xLi one-dimensional perovskite structure metal halide scintillation crystal.
5. The Li of any one of claims 1-2 + Use of a doped perovskite metal halide scintillation crystal, characterized in that The application of the scintillation crystal in the field of X-ray, gamma-ray or neutron detection.