CN112239667B

CN112239667B - Red light plastic scintillator and preparation method and application thereof

Info

Publication number: CN112239667B
Application number: CN202011102679.7A
Authority: CN
Inventors: 刘应都; 王存; 谢鹤楼; 胡俊; 周云; 欧阳晓平; 齐福刚; 赵镍
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2020-10-15
Filing date: 2020-10-15
Publication date: 2022-11-01
Anticipated expiration: 2040-10-15
Also published as: CN112239667A

Abstract

The invention discloses a red light plastic scintillator and a preparation method and application thereof, wherein the red light plastic scintillator consists of a scintillator matrix, and a triplet state capture agent, a singlet state capture agent and a wave-shifting agent which are co-doped in the matrix, the scintillator matrix is AS, the triplet state capture agent is Eu (DBM) 3Phen, the singlet state capture agent is TPB or BPEA, and the wave-shifting agent is DCM, and the obtained red light plastic scintillator has neutron-gamma discrimination capability, good mechanical strength and stability, and can be applied to a neutron detector.

Description

Red-light plastic scintillator and preparation method and application thereof

Technical Field

The invention relates to a red-light plastic scintillator and a preparation method and application thereof, belonging to the technical field of plastic scintillator preparation.

Background

In recent years, due to the increasing world population flow, the inspection of people and facilities for chemical, biological, radiation, nuclear and explosive threats is one of the major issues at present. Nuclear explosion, nuclear physical reaction, nuclear weapon materials and the like can release a large amount of neutrons accompanied by gamma ray background radiation; the dangerous goods and underground deposits correspondingly contain elements such as C, H, O, N or Fe, ti, gd, sm and the like, but the component ratios of the elements are obviously different from those in the conventional situation, and forbidden goods or ground space resource distribution can be judged according to the energy spectrum or the change of the absorbed situation after neutrons and the elements act. Therefore, the neutron detection is involved in national defense safety, experimental nuclear physical measurement, nuclear medicine imaging, sea, land and air resource reserve detection, space radiation early warning and the like. Due to the universality of gamma transition radiation, the problem of neutron discrimination under the background of gamma rays needs to be solved while neutrons are measured, and the development and application of a related neutron detector are critical.

At present, plastic scintillator detector materials for neutron detection have been widely used in nuclear medicine imaging, national defense security, and particle physics detection due to their advantages of low preparation cost, fast response time, and being easily processed into various complex shapes. However, it remains challenging to develop plastic scintillators with faster response times (ns), better n/γ discrimination capabilities (Andrew n. Mabe, andrew m. Glenn, et al. Nuclear Instruments and Methods in Physics Research a 806 (2016) 80-86 r. D. Breukers, c.m. Bartle, et al. Nuclear Instruments and Methods in Physics Research a 701 (2013) 58-61). Therefore, it is very important to search and master a method for preparing a novel plastic scintillator having excellent properties.

In neutron detection, the main challenge in the detection of fast neutrons is how to effectively separate the impulse response of the neutrons from the gamma background signal. Unlike alpha or beta rays, neutrons respond similarly to gamma rays in plastic scintillator materials. However, the gamma and neutron ionization mechanisms are slightly different, and differences in signal spectral shape can be generated, and according to the shape differences, n/gamma discrimination which is separated and is attributed to neutrons or gamma responses can be realized. Specifically, on the principle of discriminating n/gamma rays by a plastic scintillator detector, recoil protons are generated by the action of neutrons and a scintillator, and recoil electrons are generated by the action of gamma rays and the scintillator; both the recoil proton and the recoil electron generate two pulse components of fast and slow in the scintillator detector, wherein the fast signal pulse (b:)<10 ns) is that electrons in scintillator crystal molecules are excited by radiation to be in excited singlet state (S)₁) Is generated by directly exciting electrons to a ground state, and a slow signal pulse (. Mu.s) is generated by exciting electrons in scintillator crystal molecules to be in a Triplet state (T) by radiation₁) And then multiple energy level transitions or energy conversions (Nataleia Zaitseva, benjamin L.Rupert, et al.Nuclear Instrument)s and Methods in Physics Research A668 (2012) 88-93). In the ratio of the fast component to the slow component, the slow component generated by the action of neutrons and the scintillator material accounts for a larger proportion than gamma rays, and people can develop plastic scintillator detectors with different n/gamma ray discrimination capabilities by utilizing the difference.

The energy conversion of the triplet state is divided into two types, one is an excimer state (S) formed by diffusion-kinetic collision of Two Triplet Annihilations (TTAs) to be buried₀₊S₁) The excitation radiation produces a singlet state, which forms a delayed fluorescence component of the delay. The other is directly completed by the rare earth complex, namely, the annihilation process without triplet-triplet collision is not needed. In the latter case, eu (DBM) is usually selected as the triplet energy transfer agent₃Phen rare earth complex is used as energy transfer agent, and the triplet excitation energy of polymer base is transferred to Eu³⁺Ions generate phosphorescence emission near the emission wavelength of 612.0nm, so that the particle detection performance (decay time, self-absorption and the like) of the plastic scintillator can be effectively optimized.

However, the energy conversion of the triplet state of plastic scintillators has been mostly achieved by triplet-triplet annihilation process, which is a bimolecular process relying on intermolecular overlap of carbon 2p pi molecular orbitals, thus requiring physical spatial proximity of interacting molecules. That is, it is necessary to add a high concentration of a scintillation substance so as to provide suitable conditions for excitation energy transfer and formation of a triplet annihilation network.

However, the transparency, mechanical strength and stability of the scintillator are reduced by doping the organic scintillation dye at high concentration, the size and application field of the prepared plastic scintillator are limited, and the cost is not much different from that of the organic single crystal.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a red light plastic scintillator with long stability, mechanical strength and service life, and a preparation method and application thereof.

The invention adopts the specific technical scheme that:

the invention relates to a red light plastic scintillator, which is composed of a scintillator matrixAnd a triplet state trapping agent, a singlet state trapping agent and a wave-shifting agent which are co-doped in a matrix, wherein the scintillator matrix is AS, and the triplet state trapping agent is Eu (DBM)₃Phen, singlet state trapping agent is selected from TPB or BPEA, and wave-shifting agent is DCM.

The red light plastic scintillator provided by the invention takes styrene-acrylonitrile copolymer (AS) AS a scintillator matrix, and the triplet state trapping agent is Eu (DBM)₃Phen, 1, 4-tetraphenyl-1, 3-butadiene (TPB) or 9, 10-bis (phenylethynyl) anthracene (BPEA) as single-phase trapping agent is 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM); the invention utilizes a triplet state trapping agent as Eu (DBM)₃Phen and a singlet trapping agent TPB or BPEA AS two activation centers required for realizing Pulse Shape Discrimination (PSD) in AS, namely an organic metal complex Eu (DBM)₃Phen, which has strong spin-orbit interactions and collects excitation energy from the triplet state with an emission peak at 612 nm; the second is singlet state trapping agent TPB, which collects excited singlet state and has emission peaks at 460nm and emission peaks of the singlet state trapping agent BPEA at 467.5nm and 498 nm.

The additional wave-shifting agent 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM) is added to reduce reabsorption and transfer the fluorescence of TPB or BPEA to 618nm region, which is close to the Eu [ DBM ]3Phen fluorescence emission region.

The red light plastic scintillator provided by the invention has neutron-gamma discrimination capability and also has good mechanical strength and stability.

In a preferred embodiment, the singlet state trapping agent is BPEA.

The inventors have found that when the singlet trap is selected from BPEA, the final prepared plastic scintillator finally prepared has a higher light output.

Preferred embodiment, the Eu (DBM)₃The mass fraction of Phen in the red plastic scintillator is 2-3.5%.

In a preferable scheme, the mass fraction of the TPB in the red plastic scintillator is 2-3%.

Preferably, the mass fraction of the BPEA in the red plastic scintillator is 2-3%.

Preferably, the mass fraction of the DCM in the red light plastic scintillator is 0.02-0.06%.

As can be seen, in the present invention, the amount of organic scintillator added is small, because Eu (DBM) is the subject of the present invention₃Phen can simultaneously utilize spin-symmetric and anti-symmetric molecular excitation, the transfer energy accounts for about 75% of the total energy due to strong spin-orbit interaction, so high-concentration doping is not required, two luminescence centers exist in the plastic scintillator, and the energy of the triplet state is directly captured by a triplet energy capture agent Eu (DBM)₃Phen is transferred, so that organic dye TPB or BPEA does not need to be added at high concentration to increase the triplet-triplet collision probability, and the triplet energy transfer can be realized while the doping amount of TPB, BPEA and DCM is reduced, the transparency and the long-term stability of the scintillator are improved.

Of course, in the present invention, the fluorescent dye Eu (DBM)₃The addition amount of Phen, TPB, BPEA and DCM is effectively controlled when the fluorescent dye Eu (DBM)₃When Phen, TPB, BPEA and DCM are added too much, the plastic scintillator is not only easy to oxidize and turn yellow, but also approaches the dissolution threshold, so that the plastic flash transparency is reduced, the mechanical hardness is reduced, the long-term stability is poor, the use of the plastic scintillator is limited, and the cost of the plastic scintillator is close to that of an organic single crystal. When the amount of the fluorescent dye is too small, the medium for transferring energy is insufficient, the fluorescence intensity is too low, and the signal received by the photomultiplier is weak, so that the pulse shape discrimination quality factor value is reduced.

A preparation method of a red-light plastic scintillator comprises the following steps: one of TPB and BPEA, eu (DBM)₃Phen, DCM and styrene are mixed to obtain a solution A, acrylonitrile and AIBN are mixed to obtain a solution B, the solution A and the solution B are mixed to obtain a precursor solution, and the precursor solution is subjected to polymerization reaction under a protective atmosphere to obtain the red light plastic scintillator.

In a preferred embodiment, eu (DBM) is contained in the precursor solution₃The mass fraction of Phen is 2-3.5 wt%, the mass fraction of TPB is 2-3 wt%, the mass fraction of BPEA is 2-3 wt%, and the mass fraction of DCM is 0.02-0.06 wt%.

In a preferred embodiment, the mass ratio of styrene to acrylonitrile is 75-95: 5-25, preferably 75.

The inventors found that a plastic scintillator with uniform polymerization and high light yield can be obtained by controlling the mass ratio of styrene to acrylonitrile within the above range, and in the present invention, the mass ratio of styrene to acrylonitrile is set to 75:25, this represents the bulk copolymeric constant composition of styrene (St) and Acrylonitrile (AN). The mass ratio of St/AN can be adjusted by the amount of the solution A and the solution B in the mixed solution, and different mass ratios can be adopted according to different application requirements.

Preferably, the addition amount of the azodiisobutyronitrile is 0.03 to 0.04wt% of the total mass of the styrene and the acrylonitrile.

Preferably, the polymerization reaction process comprises the steps of firstly keeping the temperature at 40-50 ℃ for 12-14 h, then increasing the temperature to 80-100 ℃ at the speed of increasing the temperature to 6-12 ℃ every 5-10 h, keeping the temperature for 12-24 h, then reducing the temperature to 40-50 ℃ at the speed of 5-10 ℃/h, and then keeping the temperature for 6-12 h.

In the polymerization process, the gentle progress of the polymerization reaction can be ensured by controlling the temperature rise program, the complete monomer reaction is ensured, and in addition, the gradient temperature reduction is adopted in the temperature reduction process to avoid the deformation of the plastic scintillator, so that the performance of the obtained plastic scintillator is optimal.

In the actual operation process, the surface of the finally obtained sample is ground and polished.

Preferred embodiment, the Eu (DBM)₃The process for preparing Phen is as follows:

adding 10.0mmol of Eu₂O₃Dissolving in excess (6.0 mo 1/L) hydrochloric acid, rotary evaporating to near dryness to obtain EuCl₃·6H₂Dissolving the O crystal with absolute ethyl alcohol to prepare 0.1mo1/L solution. Dibenzoylmethane (DBM) (6.0 mmol), 1, 10-phenanthroline (2.0 mmol) and sodium hydroxide (6.0 mmol) were dissolved in 20.0ml of ethanol and heated with continuous stirring to give a ligand solution. Then subjecting the EuCl₃·6H₂And adding the O solution into the ligand solution, and cooling and washing the obtained mixture to obtain a yellowing product. The resulting yellow product was refined by recrystallization from ethanol, followed by the addition of benzene (30)0 ml) and heptane (30.0 ml) gave a precipitate. Finally drying in an oven at 80 ℃ for 8.0h to obtain Eu (DBM)₃phen powder.

The invention relates to a red light plastic scintillator which is applied to a neutron detector.

The principle and the advantages are as follows:

in the present invention, only styrene contributes to scintillation. The copolymerization system is adopted, and the acrylonitrile is introduced because the acrylonitrile has stronger polarity. In order to ensure that the polar fluorescent dye DCM is completely dissolved, and the DCM has short fluorescence wavelength and low fluorescence quantum efficiency in nonpolar PS, and has red-shifted fluorescence wavelength by 40.0-50.0nm in AS, and the fluorescence is enhanced.

In the present invention, in order to obtain a uniformly polymerized and high light yield plastic scintillator, the mass ratio of styrene to acrylonitrile is set to 75:25, this represents the bulk copolymeric constant composition of styrene (St) and Acrylonitrile (AN).

The energy transfer process of the present invention is described as follows: styrene (St) as an energy donor, TPB or BPEA as a first energy acceptor (singlet trap), DCM as a second energy acceptor; metal complex (Eu (DBM)₃Phen) as a triplet-scavenger receptor.

The invention has the advantages and effects that: the triplet components carry particle (neutron, gamma ray) information with the ionization capability incapable of radiating in the material, wherein the ionization capability (energy deposition rate per unit length dE/dx) of recoil proton generated by the neutron is stronger than that of electrons generated by the gamma ray, and the fraction of the generated slow fluorescence components is larger, which is the key for screening n/gamma. According to the invention, the solubility of the fluorescent agent is improved by adopting the copolymerization matrix; by Eu³⁺The triplet energy can be efficiently transferred by direct capture without adding a high-concentration triplet energy transfer agent, so that the stability and the mechanical strength of the plastic scintillator are improved, the service life is prolonged, and the scintillator has considerable commercial application prospect.

Drawings

FIG. 1 is a diagram showing an excitation-emission spectrum of example 4 of the present invention.

FIG. 2 is a graph showing an excitation-emission spectrum of comparative example 1 of the present invention.

FIG. 3 is a graph showing the photoluminescence decay curves obtained by exciting with 290.0nm excitation light and monitoring the fluorescence lifetime at wavelengths of 612.0nm and 618.0nm in example 4 of the present invention.

FIG. 4 is a graph of the photoluminescence decay obtained from example 4 of the present invention when excited by a 375.0nm picosecond laser and monitored for fluorescence lifetime at 618.0nm wavelength.

Detailed Description

Hereinafter, eu (DBM) of the present invention is described by way of examples₃The preparation of Phen/TPB/DCM/AS plastic scintillators is further illustrated.

Example 1

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.001g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.125g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and solution B, and performing ultrasonic homogenization to obtain Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(2) And adding the precursor solution into a silicate glass ampoule, and uniformly mixing. Then vacuumizing for 3.0min, then blowing nitrogen for 2.0min, and repeating the operation for at least 3 times. And finally sealing under vacuum condition.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 29.67%. Pulse shape discrimination quality factor FOM =1.15. The plastic flashing has no bubble inside and high transparency.

Example 2

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.002g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.125g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and solution B, and performing ultrasonic homogenization to obtain Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(2) And adding the precursor solution into a silicate glass ampoule, and uniformly mixing. Then, the vacuum is firstly pumped for 3.0min, then the nitrogen is blown for 2.0min, and the operations are repeated for at least 3 times. And finally sealing under vacuum condition.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 30.17%. Pulse shape discrimination quality factor FOM =1.22. The plastic flashing has no bubble inside and high transparency.

Example 3

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.003g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.125g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and solution B, and performing ultrasonic homogenization to obtain Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(2) And adding the precursor solution into a silicate glass ampoule, and uniformly mixing. Then, the vacuum is firstly pumped for 3.0min, then the nitrogen is blown for 2.0min, and the operations are repeated for at least 3 times. And finally sealing under the vacuum condition.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 30.28%. Pulse shape discrimination quality factor FOM =1.18. The plastic flashing has no bubble inside and high transparency.

Example 4

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.001g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.15g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and solution B, and performing ultrasonic homogenization to obtain Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 27.13%. Pulse shape discrimination quality factorChild FOM =1.25. The plastic flashing has no bubble inside and high transparency.

The following is an excitation-fluorescence spectrum and attenuation curve analysis based on the red-light plastic scintillator obtained in example 4:

1. excitation-fluorescence spectroscopy

FIG. 1 is an excitation-fluorescence spectrum of example 4; as can be seen, there is a broad excitation peak at 290.0nm, which is attributed to the conversion of styrene to Eu³⁺Electron energy level transition of 4f orbital, the peak at 400.0nm being assigned to Eu³⁺The f-f orbital transition of (1). Eu at emission peaks of 612.0nm and 618.0nm³⁺Characteristic emission peak of, i.e. Eu (DBM)₃Phen acts as a capture agent that delays the transfer of the fluorescent component (triplet energy).

Fig. 2 is an excitation-fluorescence spectrum of comparative example 1. The triplet state trapping agent is not added in the comparative example 1, so the spectrum shows the fluorescence resonance energy transfer process of the singlet state trapping agent and the wave shifting agent, and the comparative example 1 has an excitation peak at 390.0nm and is a dispersed broadband. Broadband emission is exhibited at 618.0nm, indicating spectral overlap between the donor dye TPB and the acceptor dye DCM in the material, with fluorescence resonance energy transfer of TPB and DCM into a transfer mode of the prompt fluorescent component (singlet energy).

The prompt fluorescence component and the delayed fluorescence component in the scintillator material prepared in example 4 are emitted in the red region and are close to each other, which shows that the prompt and delayed signals emitted by the scintillator prepared by the method can be well collected by the photomultiplier tube working in the receiving wavelength range at the same time.

2. Analysis of attenuation curve

FIG. 3 is a photoluminescence decay curve obtained by monitoring the ultraviolet excitation at 290nm and the wavelength at 612.0nm in example 4, and Eu [ DBM ] can be known through fitting analysis]₃The Phen additive formed delayed component (triplet) scintillation pulses with decay times of 415.0 μ s and 418.0 μ s at 612.0nm and 618.0nm, respectively.

FIG. 4 is a graph of the decay of photoluminescence from example 4 at 618.0nm after 375.0nm picosecond laser excitation. The additives TPB and DCM formed a prompt component (singlet) scintillation pulse with a decay time of 3.8ns at 618.0nm as determined by fitting analysis.

Therefore, the decay time of the prompt component is 10 ten thousand times that of the delay component, and the neutron gamma screening can be effectively realized through the different proportions of the prompt component and the delay fluorescent component.

Example 5

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.002g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.15g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and then the temperature is kept for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 27.45%. Pulse shape discrimination quality factor FOM =1.29. The plastic flashing has no bubble inside and high transparency.

Example 6

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.003g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.15g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIB)N) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 29.10%. Pulse shape discrimination quality factor FOM =1.27. The plastic flash has no bubble inside and high transparency.

Example 7

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.001g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.175g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. The surface of the sample which is completely polymerized is ground and polished to obtainTo Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃The fluorescence peak of Phen is 612nm and 618nm, the triplet state fluorescence decay lifetime tau =415 mus and tau =418 mus, the DCM fluorescence peak is 618nm, and the singlet state fluorescence decay lifetime tau =3.8ns. The fluorescence quantum yield was 28.37%. Pulse shape discrimination quality factor FOM =1.25. The plastic flash has no bubble inside and high transparency.

Example 8

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.002g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.175g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) were mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and solution B, and performing ultrasonic homogenization to obtain Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and then the temperature is kept for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 29.63%. Pulse shape discrimination quality factor FOM =1.26. The plastic flash has no bubble inside and high transparency.

Example 9

(1) 0.01g of 1, 4-tetraphenyl-1, 3-butadiene (TPB), 0.003g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.175g of Eu (DBM)₃Phen and 3.75g of styrene (St)Mixing and stirring uniformly to form a solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(2) And adding the precursor solution into a silicate glass ampoule, and uniformly mixing. Then vacuumizing for 3.0min, then blowing nitrogen for 2.0min, and repeating the operation for at least 3 times. And finally sealing under the vacuum condition.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and the temperature is preserved for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/TPB/DCM/AS plastic scintillator. In AS, eu (DBM)₃The fluorescence peak of Phen is 612nm and 618nm, the triplet state fluorescence decay lifetime tau =415 mus and tau =418 mus, the DCM fluorescence peak is 618nm, and the singlet state fluorescence decay lifetime tau =3.8ns. The fluorescence quantum yield was 29.78%. Pulse shape discrimination quality factor FOM =1.28. The plastic flash has no bubble inside and high transparency.

Example 10

(1) 0.01g of 9,10-bis (phenylethynyl) anthracene (BPEA), 0.002g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.15g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) are mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/BPEA/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then at 10 ℃h, cooling to 50 ℃, and then preserving heat for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/BPEA/DCM/AS plastic scintillators. In AS, eu (DBM)₃Phen has fluorescence peaks at 612nm and 618nm, triplet fluorescence decay lifetimes τ =415 μ s and τ =418 μ s, DCM has a fluorescence peak at 618nm, singlet fluorescence decay lifetime τ =3.8ns. The fluorescence quantum yield was 46.2%. Pulse shape discrimination quality factor FOM =1.33. The plastic flashing has no bubble inside and high transparency.

Example 11

(1) 0.01g of 9,10-bis (phenylethynyl) anthracene (BPEA), 0.003g of 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran (DCM), 0.15g of Eu (DBM)₃Phen and 3.75g of styrene (St) were mixed and stirred well to form a solution denoted as solution A; 0.001g of Azobisisobutyronitrile (AIBN) and 1.25g of Acrylonitrile (AN) were mixed and stirred uniformly to form a solution B; and finally, mixing the uniformly stirred solution A and the solution B, and performing ultrasonic homogenization to obtain a Eu (DBM) 3Phen/TPB/DCM/AS precursor solution. Wherein the mass ratio of styrene to acrylonitrile is 75:25.

(3) The temperature is kept for 12h at 50 ℃, then the temperature is increased to 100 ℃ every 6h, and the temperature is kept for 12h. Then the temperature is reduced to 50 ℃ at the speed of 10 ℃/h, and then the temperature is kept for 12h. Grinding and polishing the surface of the sample with complete polymerization to obtain Eu (DBM)₃Phen/BPEA/DCM/AS plastic scintillators. In AS, eu (DBM)₃The fluorescence peak of Phen is 612nm and 618nm, the triplet state fluorescence decay lifetime tau =415 mus and tau =418 mus, the DCM fluorescence peak is 618nm, and the singlet state fluorescence decay lifetime tau =3.8ns. The fluorescence quantum yield was 51.43%. Pulse shape discrimination quality factor FOM =1.30. The plastic flashing has no bubble inside and high transparency.

Comparative example 1

The conditions were the same as in example 4, and the conditions were the same as in example 4 except that no triplet-trapping agent Eu (DBM) was added₃Phen。612nm、The narrow peak emission at 618nm disappeared; the DCM fluorescence peak is 618nm, and the singlet state fluorescence decay lifetime is tau =3.8ns. The fluorescence quantum yield was 30.71%. Compared to example 1, there is no pulse shape discrimination capability.

Comparative example 2

The other conditions were the same as in example 1 except that Acrylonitrile (AN) as a cosolvent in the matrix was changed to methacrylic acid (MAA) so that Eu (DBM) in the scintillator₃Phen fluorescence quenches. Compared with example 1, the fluorescence spectrum has no characteristic peaks of the triplet state trapping agent Eu (DBM) 3Phen with the wavelengths of 612nm and 618 nm.

Comparative example 3

The other conditions were the same as in example 1 except that the singlet-state trapping agent TPB was changed to PPO, so that the fluorescence of the singlet-state trapping agent in the scintillator was quenched, and Eu (DBM) was found by the test₃Phen has a dispersion broadband absorption peak wavelength of 260-400 nm, and PPO has an emission peak wavelength of 375nm. Due to the emission spectrum of PPO and Eu (DBM)₃The absorption spectra of Phen overlap. Compared to example 1, the singlet broad peak emission disappeared.

Comparative example 4

Otherwise, the same conditions as in example 1 were followed except that Acrylonitrile (AN) as a cosolvent in the matrix was changed to Methyl Methacrylate (MMA), and the fluorescence spectrum was observed to change the position of the fluorescence peak of DCM in the scintillator from 618nm to around 560 nm. Compared with example 1, the singlet broad peak emission cannot be compared with Eu (DBM)₃The fluorescence of Phen is in the red region.

Comparative example 5

Otherwise, the conditions were the same as in example 1 except that the wave-shifting agent (DCM) was changed to coumarin PDI and fluorescence spectroscopy revealed that broad-peak emission of the singlet-state scavenger in the scintillator occurred near 450nm and that broad-peak emission at 618nm disappeared. Compared with example 1, the singlet broad peak emission cannot be compared with Eu (DBM)₃The fluorescence of Phen is in the red region.

Comparative example 6

The other conditions were the same as in example 1 except that the temperature increase rate was changed from 5 ℃ per 6h to 100 ℃ to 5 ℃ per 0.5h, and the inside of the obtained plastic scintillator had bubbles and polymerization was not uniform as compared with example 1.

Comparative example 7

The other conditions were the same as in example 1 except that the amount of DCM added was increased from 0.02wt% to 1wt% based on the total mass, and the resulting plastic scintillator was inferior in transparency and decreased in light yield as compared with example 1.

Comparative example 8

The other conditions were the same as in example 1 except that the amount of TPB added was increased from 2wt% to 10wt% based on the total mass, and the resulting plastic scintillator had poor transparency, poor long-term stability, and easy oxidation, as compared with example 1.

Claims

1. A red-light plastic scintillator, comprising: the red light plastic scintillator consists of a scintillator matrix, and a triplet state capture agent, a singlet state capture agent and a wave-shifting agent which are co-doped in the matrix, wherein the scintillator matrix is AS, and the triplet state capture agent is Eu (DBM)₃Phen, BPEA as single heavy-state trapping agent and DCM as wave-shifting agent;

the Eu (DBM)₃The mass fraction of Phen in the red light plastic scintillator is 2 to 3.5 percent;

the mass fraction of the BPEA in the red light plastic scintillator is 2 to 3 percent;

the mass fraction of the DCM in the red light plastic scintillator is 0.02 to 0.06 percent;

the AS is styrene-acrylonitrile copolymer, the DBM is dibenzoylmethane, the Phen is 1, 10-phenanthroline, the BPEA is 9, 10-bis (phenylethynyl) anthracene, and the DCM is 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) -4H-pyran.

2. The method for preparing a red-light plastic scintillator according to claim 1, wherein: the method comprises the following steps: taking BPEA, eu (DBM)₃Mixing Phen, DCM and styrene to obtain a solution A, mixing acrylonitrile and azobisisobutyronitrile to obtain a solution B, mixing the solution A and the solution B to obtain a precursor solution, and carrying out polymerization reaction under a protective atmosphere to obtain the red light plastic scintillator;

in the precursor solution, eu (DBM)₃The mass fraction of Phen is 2-3.5 wt%, the mass fraction of BPEA is 2-3 wt%, and the mass fraction of DCM is 0.02-0.06wt%.

3. The method for preparing a red-light plastic scintillator according to claim 2, wherein: the mass ratio of the styrene to the acrylonitrile is 75 to 95:5 to 25.

4. The method for preparing a red-light plastic scintillator according to claim 2, wherein: the addition amount of the azodiisobutyronitrile is 0.03 to 0.04wt% of the total mass of the styrene and the acrylonitrile.

5. The method for preparing a red plastic scintillator according to claim 2, wherein: the polymerization reaction process is that the temperature is kept for 12 to 14h at the temperature of 40 to 50 ℃, the temperature is raised to 80 to 100 ℃ at the speed of rising every 5 to 10h and 6 to 12 ℃, the temperature is kept for 12 to 24h, then the temperature is lowered to 40 to 50 ℃ at the temperature of 5 to 10 ℃/h, and the temperature is kept for 6 to 12h.

6. The method for preparing a red plastic scintillator according to claim 2, wherein: the Eu (DBM)₃Phen is prepared by adding 10.0mmol of Eu₂O₃Dissolving in 6.0 mol/L hydrochloric acid, rotary evaporating to near dryness to obtain EuCl₃·6H₂Dissolving O crystal in anhydrous alcohol to obtain 0.1 mol/L solution, dissolving 6.0mmol of dibenzoylmethane DBM, 2.0mmol of 1, 10-phenanthroline and 6.0mmol of sodium hydroxide in 20.0mL of alcohol, continuously stirring and heating to obtain ligand solution, and adding EuCl₃·6H₂Adding O solution into ligand solution, cooling and washing the obtained mixture to obtain yellow product, recrystallizing the obtained yellow product with ethanol, adding 30.0mL benzene and 30.0mL heptane to obtain precipitate, and drying in oven at 80 deg.C for 8.0 hr to obtain Eu (DBM)₃phen powder.

7. The use of a red plastic scintillator according to claim 1, wherein: the red-light plastic scintillator is applied to a neutron detector.