Cluster scintillator based on diphenyl-2-pyridine phosphine and cuprous iodide as well as preparation method and application of cluster scintillator

Abstract

The invention relates to a copper cluster scintillator constructed on the basis of diphenyl-2-pyridine phosphine and cuprous iodide and a preparation method and application of the copper cluster scintillator. The preparation method comprises the following steps: constructing a copper cluster scintillator by using diphenyl-2-pyridine phosphine and cuprous iodide, and preparing the copper cluster scintillator into a semitransparent scintillator film by using polyvinylpyrrolidone as a high-molecular polymer matrix and polyethylene glycol terephthalate as a spin-coating substrate; the scintillator film and a photomultiplier are optically coupled and integrated with nuclear electronics equipment to develop an alpha / beta particle pollution monitor. The copper cluster scintillator provided by the invention has excellent X-ray luminescence performance, and can realize high-sensitivity scintillation response to alpha / beta particles; the surface pollution monitor can realize sensitive detection of alpha / beta particles in the environment, and has important application value in the field of environmental radiation detection.

Description

Technical Field

[0001] The present invention belongs to the field of X-ray scintillators, and in particular relates to a type of copper cluster scintillator Cu4I4(DPPPy)2, a preparation method thereof and application thereof in α / β particle detection. Background Art

[0002] High-energy radiation has greatly promoted the development of modern medicine, industry, and scientific research. However, excessive ionizing radiation (including alpha particles, beta particles, gamma rays, and X-rays) has become a public health concern, posing a threat to human safety and the living environment. Therefore, proper control and detection of ionizing radiation are crucial prerequisites for ensuring the safe use of high-energy radiation.

[0003] Scintillators convert high-energy ionizing radiation into visible light and play a crucial role in the construction of scintillator detectors for high-energy radiation detection. When particles or radiation interact with scintillators, the resulting secondary electrons ionize and excite the scintillator molecules. During the de-excitation process, a large number of visible photons are emitted.

[0004] Scintillator detectors are an important type of radiation detector, offering advantages such as simple structure, high sensitivity, and a good cost-effectiveness. However, there is a lack of high-performance scintillators that can produce highly sensitive responses to ambient radiation, particularly α / β particles. Therefore, the development of new scintillators is crucial for advancing ambient radiation detection technology towards higher efficiency and precision.

[0005] Traditional commercial scintillators are typically inorganic salt crystals containing heavy metal elements, such as CsI:Tl and PbWO4. While these scintillators exhibit excellent scintillation performance, they also pose an environmental pollution risk. Furthermore, traditional inorganic scintillators are typically prepared into large crystals using the Czochralski method, a method that requires harsh preparation conditions, has limited environmental adaptability, and is costly to produce. Therefore, in the context of promoting environmental sustainability, finding scintillators with excellent comprehensive performance to meet the diverse needs of environmental radiation detection is a task of great value and challenge. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention provides a preparation method and application of a copper cluster (Cu4I4(DPPPy)2) scintillator based on diphenyl-2-pyridylphosphine and cuprous iodide.

[0007] The present invention also provides a preparation method of a semi-transparent scintillator film Cu4I4(DPPPy)2@PET and an application thereof in detecting α or β particles.

[0008] The technical solution adopted in the present invention is:

[0009] A method for preparing a copper cluster scintillator Cu4I4(DPPPy)2 comprises the following steps:

[0010] (1) dissolving the organic ligand diphenyl-2-pyridylphosphine in dichloromethane, dissolving the metal source cuprous iodide in acetonitrile, and then mixing the two; stirring at room temperature for 4-6 hours to obtain a suspension;

[0011] (2) The suspension is vacuum filtered to obtain a solid and a filtrate; the obtained solid is the target product, copper cluster scintillator.

[0012] Preferably, the molar ratio of diphenyl-2-pyridylphosphine to cuprous iodide is 1:2; and the stirring time in step (2) is 5 hours.

[0013] The obtained filtrate is placed in a diffusion container, ether diffusant is added to the diffusion container, and the container is sealed and allowed to stand at room temperature; light yellow flaky crystals are precipitated at the bottom of the diffusion container, which is part of the copper cluster scintillator in the filtrate.

[0014] A method for preparing a semi-transparent scintillator film Cu4I4(DPPPy)2@PET comprises the following steps:

[0015] (1) dissolving an organic ligand diphenyl-2-pyridylphosphine in a dichloromethane solvent to obtain an organic ligand solution, adding polyvinylpyrrolidone to the solution, and subjecting the solution to ultrasonic treatment to obtain a stable micelle solution;

[0016] (2) dissolving cuprous iodide in acetonitrile, adding the solution to the micellar solution of step (1), and stirring continuously at room temperature for 2 hours to convert the solution into a stable emulsion;

[0017] (3) The emulsion is evenly coated on a polyethylene terephthalate substrate, and a semi-transparent scintillator film with uniform thickness is obtained by a spin coating process.

[0018] The molar ratio of diphenyl-2-pyridylphosphine to cuprous iodide is 1:2.

[0019] The application of the translucent scintillator film Cu4I4(DPPPy)2@PET in detecting alpha particles and beta particles.

[0020] Beneficial effects of the present invention

[0021] (1) The method for preparing the copper cluster scintillator of the present invention uses diphenyl-2-pyridylphosphine and cuprous iodide as raw materials. The method has a simple process and is easy to operate and control.

[0022] (2) This invention uses polyvinyl pyrrolidone as a polymer matrix and polyethylene terephthalate as a spin-coating substrate to fabricate a copper cluster scintillator into a semi-transparent scintillator film, Cu4I4(DPPPy)2@PET. This scintillator film is optically coupled to a photomultiplier tube and integrated with nuclear electronics to develop an α / β particle contamination monitor. This monitor can sensitively detect α / β particles in the environment and has important application value in the field of low-dose environmental radiation detection.

[0023] (3) The present invention uses cluster scintillator materials as the core components of α / β particle detectors, which have comprehensive advantages such as high detection efficiency, rapid response, flexible design, good environmental adaptability and low cost. It is an efficient and practical choice in radiation monitoring and nuclear detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The crystal structure and morphology of the copper cluster scintillator of the present invention;

[0025] Figure 2 Hydrophobic angle detection of the copper cluster scintillator sample of Example 1;

[0026] Figure 3 The relationship between the X-ray luminescence intensity and X-ray dose of the copper cluster scintillator sample of Example 1;

[0027] Figure 4 Changes in X-ray luminescence intensity of the copper cluster scintillator sample of Example 1 under high-dose X-ray irradiation;

[0028] Figure 5 Spectral measurement and relative light yield of copper cluster scintillator standards and the copper cluster scintillator of Example 1;

[0029] Figure 6 Schematic diagram of the process flow of the Cu4I4(DPPPy)2@PET semi-transparent scintillator film of the present invention;

[0030] Figure 7 α-particle detection based on Cu4I4(DPPPy)2@PET semi-transparent scintillator film;

[0031] Figure 8 β-particle detection based on Cu4I4(DPPPy)2@PET semi-transparent scintillator film;

[0032] Figure 9 Schematic diagram of the structure of the α / β surface contamination monitor developed based on copper cluster (Cu4I4(DPPPy)2) scintillator and the detection of α / β particles.

[0033] in Figure 9 A is a schematic diagram of the structure of the surface contamination monitor. Figure 9 B, 9C, and 9D are the display results of the counter under different detection objects. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below with reference to specific embodiments.

[0035] Example 1 A method for preparing a (Cu4I4(DPPPy)2) scintillator comprises the following steps:

[0036] (1) 0.1 mmol of the organic ligand diphenyl-2-pyridylphosphine was dissolved in 10 mL of dichloromethane, and 0.2 mmol of the metal source cuprous iodide was dissolved in 10 mL of acetonitrile, and then the two were mixed; the mixture was stirred at room temperature for 5 hours, and the mixture gradually became a suspension.

[0037] (2) vacuum filtering the obtained suspension to obtain a solid and a filtrate, wherein the obtained solid is the target product, copper cluster scintillator;

[0038] (3) The filtrate was transferred to a 5 mL penicillin bottle and placed in a diffusion container. 10 mL of ether was added to the diffusion container as a diffusion agent, and the container was sealed and allowed to stand at room temperature for 48 hours. Pale yellow flaky crystals were precipitated at the bottom of the penicillin bottle. Single crystal analysis showed that the crystals were Cu4I4(DPPPy)2 scintillator.

[0039] The light yellow solid powder of step (2) and the crystals of step (3) are both target products, but exist in different forms.

[0040] Example 2 Crystal structure and performance analysis of scintillator Cu4I4(DPPPy)2.

[0041] 1. Crystal structure

[0042] The crystal structure of the scintillator obtained in Example 1 was analyzed on a Bruker D8 VENTURE diffractometer. Crystal samples were obtained using the mother solution drop method at room temperature. A loop was used under a microscope to select regular and transparent crystals for testing. The experiment was carried out at low temperature (200K) using a Cu target. Data were scanned and collected for the light source. All structures were solved by direct methods (SHELXS) and OLEX2 was used in F 2 Full-matrix least squares refinement (SHELXL-2015 module) was performed on the dataset.

[0043] The obtained crystal structure is Figure 1As shown in Figures 1A, 1B, and 1C, the four copper atoms in Cu₄I₄(DPPPy)₂ are arranged in a non-planar quadrilateral configuration, with an interplanar dihedral angle of 141.173°. Structural analysis reveals that each Cu₄ core has an iodine atom at its top and bottom, coordinated with the four copper atoms to form a distorted cubic octahedral coordination configuration. Cu₄I₄(DPPPy)₂ crystals exhibit a typical flake-like morphology.

[0044] Figure 1 A is the crystal structure of Cu4I4(DPPPy)2, Figure 1 B is the spatial dihedral angle of the Cu4I4(DPPPy)2 core, Figure 1 C is the morphology of Cu4I4(DPPPy)2 crystal under scanning electron microscope.

[0045] 2. Detection and verification of the scintillator Cu4I4(DPPPy)2

[0046] The prepared Cu4I4(DPPPy)2 scintillator was tested and verified as follows:

[0047] (1) Measurement of sample hydrophobic angle

[0048] Cu4I4(DPPPy)2 powder was pressed into smooth discs. A contact angle measuring instrument was used, water was selected as the test fluid, and the relevant parameters were set. A drop of water was placed on the surface of the Cu4I4(DPPPy)2 sample using a microsyringe. The software automatically captured the image of the drop and calculated the hydrophobic angle. The measurement was repeated five times at different locations on the same Cu4I4(DPPPy)2 sample surface, maintaining a consistent drop volume. The average value was calculated.

[0049] The results are as follows Figure 2 As shown, the hydrophobic angle of the scintillator Cu4I4(DPPPy)2 sample is 142 degrees.

[0050] (2) Relationship between the X-ray luminescence intensity of the scintillator and the X-ray dose

[0051] The radioluminescence spectra of the Cu4I4(DPPPy)2 sample under different doses of X-ray excitation were recorded using a fluorescence spectrometer. The tube voltage of the silver target X-ray tube was set to 20-50 kV and the current to 10-80 μA, and different doses of X-rays (4.5-763.2 μGy·s -1 ).

[0052] The minimum dose (detection limit) of the scintillator to X-rays is calculated by the following formula: Detection limit = 3σ / k, in μGy·s -1. Wherein, σ is the standard deviation of the background signal after 10 repeated measurements, which is about 15; k is the slope of the linear fitting curve between X-ray luminescence intensity and dose. By fitting the relationship between X-ray luminescence intensity (I) and dose (D), the linear equation is obtained: I = 509D + 38591, where I is the X-ray luminescence intensity and D is the X-ray dose (unit: μGy·s -1 ), fitting slope k = 509 (such as Figure 3 As shown). It is concluded that the detection limit of the material is 0.088μGy·s -1 .

[0053] (3) Stability of samples under high-dose X-ray irradiation

[0054] The dose rate of the fixed X-ray tube is 45.45 mGy·min -1 The XEL intensity changes of the Cu4I4(DPPPy)2 sample under continuous X-ray irradiation for 1 hour were recorded using a fluorescence spectrometer.

[0055] Test results such as Figure 4 It can be seen that the Cu4I4(DPPPy)2 sample was placed at a high dose rate (45.792mGy·min -1 ) After irradiation with X-rays for 1 hour, the radiation luminescence intensity showed no obvious attenuation.

[0056] (4) Calculation of relative light yield of samples

[0057] For powdered scintillator materials, the relative method is a common method to characterize their relative light yield. The commercial scintillator BGO with known light yield was selected as the standard sample, and the X-ray absorption cross section of the standard sample and the Cu4I4(DPPPy)2 sample was simulated using the photon cross section database ( Figure 5 A).

[0058] The X-ray absorption efficiency ( Figure 5 B).

[0059] During spectral measurements, a tablet press is used to press the standard and sample powders into discs of equal thickness and surface area. These discs are then placed in the sample chamber of a fluorescence spectrometer equipped with an X-ray tube. The slit size and X-ray tube power are set according to experimental requirements. The fluorescence spectrometer is then activated to collect the radioluminescence spectra of the standard and sample.

[0060] The spectral integration areas of the standard and sample were normalized to the same X-ray luminescence intensity. The relative light yield of the sample was calculated to be 29000 photons MeV from the ratio of the normalized spectral integration areas. -1 ( Figure 5 C).

[0061] Example 3 A method for preparing a Cu4I4(DPPPy)2@PET semi-transparent scintillator film comprises the following steps:

[0062] (1) 0.5 mmol of diphenyl-2-pyridinylphosphine was dissolved in 20 mL of dichloromethane solvent, 10 g of polyvinylpyrrolidone was added to the resulting solution, and ultrasonic treatment was performed to obtain a stable green transparent micelle solution;

[0063] (2) Dissolve 1 mmol of cuprous iodide in 20 mL of acetonitrile solvent, mix well, add the micelle solution of step (1), and continue stirring at room temperature for 2 hours to make the solution into a stable emulsion;

[0064] (3) The emulsion was dropped onto the center of a polyethylene terephthalate (PET) substrate, and then the sample emulsion was evenly spread on the substrate surface using a high-speed spin coater (spin coater speed 3000 rpm, spin coating 30 seconds) to form a translucent scintillator film with uniform thickness.

[0065] Figure 6 The figure is a schematic diagram of the process flow for preparing a translucent scintillator film according to the present invention. It can be seen that the resulting scintillator film exhibits different colors under different light conditions. Under sunlight, the color of an object is determined by the reflective and absorptive properties of its surface. Sunlight contains ultraviolet light, particularly near-ultraviolet light (UVA band, 315nm-400nm); when an object absorbs ultraviolet light, it may produce photoluminescence, a common form of which is fluorescence. In this case, the object's color is not due to reflected light, but rather to the fluorescence emitted by the substance itself.

[0066] Example 4 Detection of α / β particles using Cu4I4(DPPPy)2@PET translucent scintillator film

[0067] The α / β particle detection system mainly consists of an α / β radiation source, a nuclear instrument module chassis, a photomultiplier tube (PMT) equipped with a voltage divider circuit and a preamplifier, a spectrum amplifier, and an oscilloscope; the α radiation source is americium Activity is 0.8μCi; beta radiation source is strontium The activity is 0.2μCi.

[0068] Detection method: First, spread the sample evenly on a transparent film, with the coated side facing down, and place it above the radiation source. Position the PMT closely above the sample and use an oscilloscope to record the response of the sample to α / β particles. The results are as follows: Figure 7 、 Figure 8 .

[0069] It can be seen that the commercial scintillators anthracene and BGO (Bi4Ge3O12 )'s response signal to α particles is weaker than that of Cu4I4(DPPPy)2 materials, commercial scintillators anthracene and BGO(Bi4Ge3O 12 )'s response signal to β particles is weaker than that of Cu4I4(DPPPy)2 material.

[0070] Application Example 1: α / β particle surface contamination monitor developed with translucent scintillator film

[0071] The surface contamination monitor includes: radiation scintillation detector 1, connecting line 3, counter 2, detection window 4, see Figure 9 A. The detection window is composed of a Cu4I4(DPPPy)2@PET scintillator film, an aluminum film, a cavity coated with BaSO4 inside, and a photodetector PMT embedded in the handle.

[0072] The BaSO4 coating focuses visible light photons generated by the Cu4I4(DPPPy)2@PET scintillator film onto the PMT, while the aluminum film protects the scintillator film from contamination by external α / β radiation sources. The nuclear electronics utilize commercially available counter displays and integrated circuits. The integrated circuit system's functional modules include a main control chip, counting channels, a PMT high-voltage control module, and a PMT high-voltage module.

[0073] When testing a clean desktop, the detector can identify trace α / β particles in the air. At this time, the counter screen displays a low count of 46 and the alarm light flashes at a low frequency ( Figure 9 B).

[0074] When an alpha radiation source is placed on the table ( 0.8μCi) or β radiation source ( 0.2μCi), the counts on the counter screen increase significantly: the counts for α radiation sources exceed 4000, and the counts for β radiation sources exceed 400. At the same time, the alarm light turns to high-frequency flashing, such as Figure 9 C. Figure 9 As shown in D.

[0075] It can be seen that the α / β surface contamination monitor developed based on Cu4I4(DPPPy)2@PET scintillator film can detect excessive α / β particles in the actual environment with reliable and sensitive results.

Claims

1. A method for preparing a copper cluster scintillator Cu4I4(DPPPy)2, characterized in that: The following steps are involved: (1) dissolving the organic ligand diphenyl-2-pyridylphosphine in dichloromethane, dissolving the metal source cuprous iodide in acetonitrile, and then mixing the two; stirring at room temperature for 4-6 hours to obtain a suspension; (2) The suspension is vacuum filtered to obtain a solid and a filtrate; the obtained solid is the target product, copper cluster scintillator.

2. The method for preparing the copper cluster scintillator Cu4I4(DPPPy)2 according to claim 1, characterized in that: The molar ratio of diphenyl-2-pyridylphosphine to cuprous iodide is 1:

2.

3. The method for preparing the copper cluster scintillator Cu4I4(DPPPy)2 according to claim 1, characterized in that: The stirring time of step (2) is 5 hours.

4. The method for preparing the copper cluster scintillator Cu4I4(DPPPy)2 according to claim 1, characterized in that: The obtained filtrate is placed in a diffusion container, ether diffusant is added to the diffusion container, and the container is sealed and allowed to stand at room temperature; light yellow flaky crystals are precipitated at the bottom of the diffusion container, which is part of the copper cluster scintillator in the filtrate.

5. A method for preparing a semi-transparent scintillator thin film Cu4I4(DPPPy)2@PET, characterized in that: The method comprises the following steps: (1) dissolving an organic ligand diphenyl-2-pyridylphosphine in a dichloromethane solvent to obtain an organic ligand solution, adding polyvinylpyrrolidone to the solution, and subjecting the solution to ultrasonic treatment to obtain a stable micelle solution; (2) dissolving cuprous iodide in acetonitrile, adding the solution to the micellar solution of step (1), and stirring continuously at room temperature for 2 hours to convert the solution into a stable emulsion; (3) The emulsion is evenly coated on a polyethylene terephthalate substrate, and a semi-transparent scintillator film with uniform thickness is obtained by a spin coating process.

6. The method for preparing the semi-transparent scintillator thin film Cu4I4(DPPPy)2@PET according to claim 5, characterized in that: The molar ratio of diphenyl-2-pyridylphosphine to cuprous iodide is 1:

2.

7. Use of the semi-transparent scintillator film Cu4I4(DPPPy)2@PET according to claim 5 in detecting α particles and β particles.

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