CN113652226B

CN113652226B - CuI-Cl-PS composite scintillator and preparation method and application thereof

Info

Publication number: CN113652226B
Application number: CN202111004891.4A
Authority: CN
Inventors: 刘小林; 郝书童; 顾牡
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2021-08-30
Filing date: 2021-08-30
Publication date: 2023-04-28
Anticipated expiration: 2041-08-30
Also published as: CN113652226A

Abstract

The invention relates to a CuI/Cl-PS composite scintillator, and a preparation method and application thereof, comprising the following steps: fully grinding and mixing CuI and CuCl powder according to a certain proportion; placing the mixed powder in a tubular annealing furnace for solid phase reaction, and using argon as protective atmosphere; taking out the reacted CuI/Cl powder, grinding and drying; pouring CuI, cl and polystyrene powder into a certain amount of toluene, and fully stirring until the PS powder is completely dissolved; pouring the mixture into a mold, and sealing and preserving; putting the mould into a fume hood, and evaporating and drying; demolding, cutting and polishing the dried compound; and (3) putting the composite sheet into a drying oven for annealing to finally obtain the CuI/Cl-PS composite scintillator. Compared with the prior art, the invention has the advantages of simple preparation method, low requirement on equipment, good luminous stability and the like. The prepared CuI-Cl-PS composite scintillator can be used for ultra-fast hard X-ray detection and imaging.

Description

CuI-Cl-PS composite scintillator and preparation method and application thereof

Technical Field

The invention relates to the technical field of X-ray detection and imaging, in particular to a CuI: cl-PS composite scintillator, and a preparation method and application thereof.

Background

With the development of high energy physical experiment devices, such as free electron lasers (XFEL), inertial confinement nuclear fusion devices (ICF), and radiation-to-substance interaction under extreme conditions (MaRIE) programs, the need for ultra-fast hard X-ray detection and imaging has arisen. At present, a silicon-based semiconductor is mostly adopted for direct detection of X-rays at home and abroad, and the detector can well meet the X-ray detection requirements of frame frequency below 10MHz and 15keV, but has great limitation on ultra-fast hard X-ray detection.

The detection and imaging of ultra-fast hard X-rays involves two key factors: time resolution and cut-off power. The inorganic scintillating material has high energy deposition efficiency on high-energy X rays, and the decay time of the sub-nanosecond ultrafast scintillator is beneficial to avoiding signal accumulation, so that the time resolution of hard X ray detection is improved. The current electrodeless scintillation materials expected to be used for ultra-fast hard X-ray detection are mainly cesium lead halogen perovskite (CsPbX) ₃ X=cl, br, I), barium fluoride (BaF ₂ ) Zinc oxide (ZnO), gamma cuprous iodide (γ -CuI), and the like. Wherein CsPbX ₃ The nanocrystalline has high fluorescence quantum efficiency, adjustable luminescence wavelength and attenuationTime is dependent on its composition and size, which can be on the order of sub-nanoseconds. However, at present, cesium lead halogen perovskite still has a plurality of problems to be solved, such as low stability, ambiguous scintillation luminescence mechanism and the like. BaF (Baf) ₂ The yttrium doped light-emitting material has two light-emitting components, namely a fast light-emitting component and a slow light-emitting component, and the slow light-emitting component is effectively restrained by yttrium doping, but the slow light-emitting component is still strong, and further research is needed. The ZnO material also has two luminous components, namely a fast luminous component and a slow luminous component, can be basically inhibited from emitting light by hydrogen annealing, is expected to be applied to various radiation detection, but has serious self-absorption of a crystal material, so that the light yield is rapidly reduced, and the application of the ZnO material is limited. The gamma-CuI material has ultra-fast near-band edge luminescence at 410-430nm, decay time is about 130ps, meanwhile, deep energy level luminescence at 680-720nm is about 100ns or more, slow luminescence components can be almost completely inhibited by doping the gamma-CuI powder, and the luminescence performance is improved, but the gamma-CuI material still has the problems of serious luminescence degradation, stronger crystal self-absorption and the like at present.

At present, no report exists that gamma-CuI is compounded with an organic material at home and abroad, and the problem of luminescence degradation is greatly improved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the CuI/Cl-PS composite scintillator for ultra-fast hard X-ray detection, which has the advantages of high time resolution, good luminous stability, good mechanical property, simple structure, easy preparation and low cost, and the preparation method and the application thereof.

The aim of the invention can be achieved by the following technical scheme:

the scintillator disclosed by the invention is based on CuI powder, and is doped with Cl by a solid phase reaction method, so that the purposes of completely inhibiting deep-level luminescence, enhancing near-band edge luminescence with subnanosecond decay time and greatly optimizing the luminescence performance are achieved. In addition, the CuI/Cl powder and the PS material are compounded by a dissolution evaporation method to obtain the large-size flake scintillator, so that the problem of luminescence degradation of the CuI material in air can be effectively solved, the requirement of ultra-fast hard X-ray detection in the future is met, and the method has important scientific significance and application value, and the specific scheme is as follows:

the preparation method of the CuI/Cl-PS composite scintillator comprises the steps of preparing the CuI/Cl powder by performing Cl doping on the CuI powder by a solid phase reaction method, then compounding the CuI/Cl powder with a Polystyrene (PS) material by a dissolution evaporation method, and finally preparing the CuI/Cl-PS composite scintillator by annealing treatment.

Further, the method comprises the steps of:

(1) Performing Cl doping on the CuI powder by using a solid phase reaction method to obtain CuI: cl powder;

(2) Taking out the reacted CuI/Cl powder, grinding and drying;

(3) Pouring CuI, cl and PS powder into a solvent, and fully stirring until the PS powder is completely dissolved;

(4) Pouring the mixture into a mold, and hermetically preserving for a period of time;

(5) Evaporating and drying the mixture; demolding, cutting and polishing the dried mixture to obtain a CuI: cl-PS composite sheet;

(6) And (3) annealing the CuI/Cl-PS composite sheet to finally obtain the CuI/Cl-PS composite scintillator.

Further, the specific steps of the step (1) include:

(1-1) mixing CuI with CuCl powder, and grinding,

(1-2) pre-aerating the mixed powder with an inert gas;

(1-3) heating and raising the temperature in an inert gas atmosphere, preserving the heat, and naturally cooling to finish the preparation of the CuI/Cl powder.

The inert gas injection rate is 50-200sccm.

Further, the molar ratio of CuI to CuCl is (99-80): (1-20), preferably 90:10.

Further, the heating temperature in the step (1-3) is 400-500 ℃, preferably 460 ℃, and the heat preservation time is 0.5-3h.

Further, the grinding time is 10-30min,

further, the mass ratio of CuI to Cl to PS powder is (0.5-5): (99.5-95), preferably 2:98, the annealing temperature is 75-85 ℃, the annealing time is 20-40min, and the cooling rate is 1-5 ℃/min.

Further, the drying temperature is 75-85 ℃ and the drying time is 12-24 hours; the stirring time is 0.5-2h; the preservation time is 1-3 days; the evaporating and drying time is 5-10 days.

A CuI/Cl-PS composite scintillator prepared by the method described above.

An application of the CuI-Cl-PS composite scintillator is disclosed, and the composite scintillator is applied to detection and imaging of ultra-fast hard X-rays.

Compared with the prior art, the invention has the following advantages:

(1) The CuI/Cl-PS composite scintillator prepared by the method has excellent luminescence performance, no slow luminescence component, good luminescence stability and adjustable size. The CuI-Cl-PS composite scintillator can be applied to ultra-fast hard X-ray detection and imaging, and achieves time resolution of subnanosecond level;

(2) The method carries out Cl doping on the CuI powder through solid phase reaction, completely inhibits the deep energy level luminescence of the CuI powder, and greatly optimizes the luminescence performance of the CuI powder. And the CuI/Cl powder is compounded with the polystyrene material by a dissolution evaporation method, so that the problem of luminescence degradation of the CuI material is greatly improved. The CuI-Cl-PS composite scintillator has stable components, uniform thickness, adjustable size and excellent luminescence performance, and has important application value in ultra-fast hard X-ray detection and imaging.

Drawings

FIG. 1 is a graphical illustration of a CuI: cl-PS composite scintillator in example 1;

FIG. 2 is a scanning electron micrograph of a CuI/Cl-PS composite scintillator prepared in example 1, showing the distribution of each element;

FIG. 3 is an X-ray diffraction spectrum of the CuI: cl-PS composite scintillator prepared in example 1;

FIG. 4 is a luminescence spectrum of the CuI: cl-PS composite scintillator prepared in example 1;

FIG. 5 is a near-band edge luminescence decay time spectrum of the CuI: cl-PS composite scintillator prepared in example 1;

FIG. 6 is a graph showing the trend of the near-band edge luminescence intensity of the CuI/Cl-PS composite scintillator prepared in example 1 over time.

Detailed Description

The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.

A preparation method of a novel CuI/Cl-PS composite scintillator comprises the following steps:

(1) The CuI powder is doped with Cl by a solid phase reaction method to obtain CuI:Cl powder, which comprises the following steps:

(a) Carrying out ultrasonic treatment on the corundum crucible in deionized water, then taking out, washing with absolute ethyl alcohol, drying and preserving for later use;

(b) Mixing CuI and CuCl powder in a molar ratio of (99-80): (1-20), preferably 90:10, grinding for 30min in an agate mortar, and then placing in a corundum crucible;

(c) Placing the corundum crucible in a tubular annealing furnace, injecting argon at the air flow rate of 50-200sccm, preferably 200sccm, and pre-ventilating for 1h;

(d) Regulating the argon injection rate to 50-200sccm, preferably 100sccm, heating to 400-500 ℃, preferably 460 ℃, preserving heat for 0.5-3h, preferably 30min, and naturally cooling to room temperature to finish the preparation of CuI/Cl powder;

by adjusting the molar ratio of CuI to CuCl powder, the luminescence properties of the CuI: cl powder can be controlled. The CuCl proportion is too low, and the deep level luminescence of CuI cannot be completely inhibited; the CuCl proportion is too high, and the CuCl phase appears in the powder, and a solid solution CuI: cl cannot be formed. Furthermore, too low an annealing temperature may result in incomplete solid phase reactions; the annealing temperature is too high or too long, which can lead to hardening of the powder and is disadvantageous for subsequent treatment, so that the above-mentioned reaction conditions are selected.

(2) Grinding and drying the reacted CuI/Cl powder; grinding with agate mortar for 10-30min, preferably 30min, at 80deg.C for 12-24 hr, preferably 24 hr. The longer grinding time can lead the grain diameter of the powder to be more uniform, and the longer drying time can ensure that the solvent in the powder is completely removed after grinding, so the conditions are selected.

(3) Pouring CuI, cl and PS powder into a certain amount of toluene, and fully stirring until the PS powder is completely dissolved; the mass ratio of CuI to Cl to PS powder is (0.5-5): 99.5-95, preferably 2:98, and the stirring time is 1h. The transparency and luminous intensity of the composite scintillator can be controlled by adjusting the mass ratio of CuI to Cl to PS powder, and when the concentration of the CuI to Cl powder is too low, the luminous intensity is too low and when the concentration is too high, the transparency of the scintillator can be reduced. The above concentrations are thus chosen.

(4) Pouring the mixture into a mold, and sealing and preserving; the sealed preservation temperature is 25deg.C, and the preservation time is 1-3 days, preferably 3 days. In the sealed preservation process, sufficient preservation time can ensure that bubbles in the CuI: cl-PS-toluene mixture are basically removed, so the preservation time is selected.

(5) Putting the mould into a fume hood, evaporating and drying; demolding, cutting and polishing the dried mixture to obtain a CuI: cl-PS composite sheet; the evaporating and drying temperature is 25deg.C, and the evaporating time is 5-10 days, preferably 10 days. In the evaporation drying process, sufficient evaporation time can ensure that toluene is basically removed by evaporation, so the evaporation time is selected.

(6) And (3) putting the composite sheet into a drying oven for annealing to finally obtain the CuI/Cl-PS composite scintillator. The annealing temperature is 80 ℃, the annealing time is 30min, and the cooling rate is 1-5 ℃/min, preferably 1 ℃/min. In the annealing cooling process, the slower cooling rate can effectively prevent the generation of stress and improve the transparency of the sample, so the cooling rate is selected.

Example 1

A preparation method of a novel CuI/Cl-PS composite scintillator comprises the steps of preparing CuI/Cl powder by performing Cl doping on the CuI powder through solid phase reaction, grinding and drying the powder, compositing the CuI/Cl powder with a PS material through a dissolution evaporation method, and finally preparing the CuI/Cl-PS composite scintillator through annealing treatment.

Specifically, the corundum crucible is subjected to ultrasonic treatment in deionized water, and then is taken out and washed by absolute ethyl alcoholWashing, drying and preserving for standby. The CuI and CuCl powders were mixed in a molar ratio of 90:10, thoroughly ground for 30min using an agate mortar, and then placed in a corundum crucible. The corundum crucible is placed in the center of a tubular annealing furnace, two aluminum oxide furnace plugs are respectively placed at two sides of the corundum crucible, argon is introduced, the flow is 200sccm, and ventilation is performed for 1h. Then regulating the flow of argon to be 100sccm, setting a temperature control program, starting heating, heating at a speed of 5 ℃/min, heating to 460 ℃, preserving heat for 30min, and naturally cooling to room temperature. And after the temperature control program is finished, closing an argon switch, and taking out reacted CuI/Cl powder. The resulting powder was ground for 30min using an agate mortar, and then dried in a drying oven at 80 ℃ for 24h. After mixing 0.4g of CuI: cl powder with 19.6g of PS powder, the mixture was poured into 40ml of toluene and stirred well until the CuI: cl powder was uniformly dispersed and the PS powder was completely dissolved. The mixture was poured into a mold and stored hermetically at room temperature (25 ℃) for 3 days using 4-layer sealing film. After the bubbles in the mixture were substantially removed, the sealing film was removed, and the mold was placed in a fume hood and evaporated at room temperature (25 ℃) for 10 days. After toluene in the mold is completely evaporated, the CuI/Cl-PS complex is taken out from the mold, cut by a cutting machine, and then 300, 1000, 3000, 10000-mesh sand paper and SiO with the grain diameter of 5 mu m are sequentially used ₂ And (3) carrying out double-sided polishing on the polishing powder to finally obtain the CuI/Cl-PS composite scintillator.

The compound scintillator real object diagram prepared in the embodiment is shown in figure 1. The scintillator is a square sheet with a side length of 20mm and a thickness of about 1 mm.

The surface scanning electron microscope photograph of the composite scintillator prepared in this example and the distribution diagram of each element are shown in fig. 2. Wherein, FIG. 2 (a) is a scanning electron microscope photograph of a CuI/Cl-PS composite scintillator, FIG. 2 (b) is a Cu element distribution diagram, FIG. 2 (c) is an I element distribution diagram, and FIG. 2 (d) is a Cl element distribution diagram; as can be seen from the graph, the surface of the composite scintillator has no obvious flaw, and Cu, I and Cl elements are uniformly distributed, so that the uniformity of X-ray detection and imaging is facilitated.

The X-ray diffraction spectrum of the composite scintillator prepared in this example is shown in fig. 3. As can be seen from the figure, the composite scintillator has a broad peak belonging to polystyrene around 20 ° and 3 distinct gamma-CuI peaks around 25.6 °, 42.5 ° and 50.3 °, respectively (111), (220) and (311), indicating that the CuI powder is still gamma-CuI phase after Cl doping and recombination with PS, and no other impurity phase occurs.

The photoluminescence spectrum and the X-ray excitation emission spectrum of the composite scintillator prepared in the embodiment are shown in figure 4; wherein fig. 4 (a) is a photoluminescence spectrum and fig. 4 (b) is an X-ray excitation emission spectrum. As can be seen from the figure, the CuI: cl-PS composite scintillator has a strong near-band edge luminescence at 434nm, and by Cl doping, its deep level luminescence originally located in the vicinity of 680-720nm is completely suppressed.

The near-band edge luminescence decay time spectrum of the composite scintillator prepared in the embodiment is shown in fig. 5. As can be seen from the graph, the decay time of the composite scintillator is about 1ns, and the instrument response limit of the Edinburgh FLS1000 type fluorescence spectrometer is reached.

The trend of the near-band edge luminescence intensity of the composite scintillator prepared in this example over time is shown in fig. 6, where fig. 6 (a) shows photoluminescence and fig. 6 (b) shows the trend of the X-ray excitation emission over time. As can be seen from the graph, after the composite scintillator is stored in the air for 6 months, the luminous intensity near the band edge can still be maintained to be more than 70%, which indicates that the luminous stability is good.

Example 2

This example is essentially the same as example 1 except that in this example, cuI and CuCl powders are mixed in a molar ratio of 99:1, thoroughly ground for 30 minutes using an agate mortar, and then placed in a corundum crucible. The corundum crucible is placed in the center of a tubular annealing furnace, two aluminum oxide furnace plugs are respectively placed at two sides of the tubular annealing furnace, argon is introduced, the flow is 50sccm, and ventilation is performed for 1h. Then, the argon flow is kept at 50sccm, a temperature control program is set, the temperature is raised, the temperature raising rate is 5 ℃/min, the temperature is kept for 30min after the temperature is raised to 400 ℃, and the mixture is naturally cooled to the room temperature. And after the temperature control program is finished, closing an argon switch, and taking out reacted CuI/Cl powder. The resulting powder was ground using an agate mortar for 10min, and then dried in a drying oven at 80 ℃ for 12h. After mixing 0.1g of CuI: cl powder with 19.9g of PS powder, the mixture was poured into 40ml of toluene, and stirred well until the CuI: cl powder was uniformly dispersed and the PS powder was completely dissolved. The mixture was poured into a mold, and the mold was put into a fume hood and evaporated at room temperature (25 ℃) for 5 days after sealing and preservation at room temperature (25 ℃) for 1 day using 4 layers of sealing film. Finally, the CuI/Cl-PS composite is taken out from the die, and is cut and polished to obtain the CuI/Cl-PS composite scintillator.

Example 3

This example is essentially the same as example 1 except that in this example, the CuI and CuCl powders are mixed in a molar ratio of 80:20, thoroughly ground for 30min using an agate mortar, and then placed in a corundum crucible. The corundum crucible is placed in the center of a tubular annealing furnace, two aluminum oxide furnace plugs are respectively placed at two sides of the tubular annealing furnace, argon is introduced, the flow is 100sccm, and ventilation is performed for 1h. Then regulating the flow of argon to 200sccm, setting a temperature control program, starting heating, heating to a speed of 5 ℃/min, heating to 500 ℃, preserving heat for 3 hours, and naturally cooling to room temperature. And after the temperature control program is finished, closing an argon switch, and taking out reacted CuI/Cl powder. The resulting powder was ground for 20min using an agate mortar, and then dried in a drying oven at 80 ℃ for 18h. After mixing 1g of CuI: cl powder with 19g of PS powder, the mixture was poured into 40ml of toluene and stirred well until the CuI: cl powder was uniformly dispersed and the PS powder was completely dissolved. The mixture was poured into a mold, and the mold was put into a fume hood and evaporated at room temperature (25 ℃) for 7 days after sealing and preservation at room temperature (25 ℃) for 2 days using 4 layers of sealing film. Finally, the CuI/Cl-PS composite is taken out from the die, and is cut and polished to obtain the CuI/Cl-PS composite scintillator.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the invention in any way, and any person skilled in the art may make modifications or alterations to the disclosed technical content to the equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. The preparation method of the CuI/Cl-PS composite scintillator is characterized in that the method utilizes a solid phase reaction method to carry out Cl doping on CuI powder to prepare CuI/Cl powder, then utilizes a dissolution evaporation method to compound the CuI/Cl powder with polystyrene material, and finally prepares the CuI/Cl-PS composite scintillator through annealing treatment, and the preparation method specifically comprises the following steps:

(2) Taking out the reacted CuI/Cl powder, grinding and drying;

(3) Pouring CuI, cl and PS powder into a solvent, and fully stirring until the PS powder is completely dissolved; the mass ratio of the CuI to the Cl to the PS powder is (0.5-5) to (99.5-95);

(4) Pouring the mixture into a mold, and sealing and preserving;

(6) Annealing the CuI/Cl-PS composite sheet to finally obtain a CuI/Cl-PS composite scintillator; the annealing temperature is 75-85 ℃, the annealing time is 20-40min, and the cooling rate is 1-5 ℃/min;

the CuI powder is still gamma-CuI phase after Cl doping and PS recombination, no other impurity phase appears, the CuI: cl-PS composite scintillator has a strong near band edge luminescence at 434nm, and by Cl doping, the deep energy level luminescence originally located near 680-720nm is completely suppressed.

2. The method for preparing the CuI:Cl-PS composite scintillator according to claim 1, wherein the specific steps of the step (1) comprise:

(1-1) mixing CuI with CuCl powder, and grinding,

(1-2) pre-aerating the mixed powder with an inert gas;

3. The method for preparing the CuI/Cl-PS composite scintillator according to claim 2, wherein the molar ratio of the CuI to the CuCl is (99-80): 1-20.

4. The method of preparing a CuI: cl-PS composite scintillator according to claim 2, wherein the heating temperature in step (1-3) is 400-500 ℃ and the holding time is 0.5-3h.

5. The method for preparing the CuI/Cl-PS composite scintillator according to claim 1, wherein the grinding time is 10-30 min.

6. The method for preparing the CuI/Cl-PS composite scintillator according to claim 1, wherein the drying temperature is 75-85 ℃ and the drying time is 12-24h; the stirring time is 0.5-2h; the preservation time is 1-3 days; the evaporating and drying time is 5-10 days.

7. A CuI: cl-PS composite scintillator prepared by the method of any one of claims 1-6.

8. Use of a CuI: cl-PS composite scintillator according to claim 7, wherein the composite scintillator is used for ultra-fast hard X-ray detection and imaging.