CN103774282B - One mixes cerium lutetium pyrosilicate scintillating fiber and electrostatic spinning synthetic method thereof - Google Patents

Abstract

A cerium-doped lutetium disilicate scintillation fiber and its electrospinning synthesis method, the chemical composition of the scintillation fiber is Lu ₂ Si ₂ O ₇ :Ce ³⁺ , Ce/Lu? The atomic weight percentage is 0.1% to 2%; the crystal phase structure is Lu ₂ Si ₂ O ₇ , and the fiber diameter is between 500 nanometers and 2 microns. The invention synthesizes cerium-doped lutetium disilicate scintillation fibers by electrospinning. The fiber prepared by the method is not only continuous, has a high aspect ratio and a smooth surface, but also has simple process steps, low production cost, controllable fiber formation and excellent scintillation performance. The cerium-doped lutetium disilicate scintillation fiber prepared by the invention has great application potential in the field of scintillation materials for nuclear medicine diagnosis such as PET.

Description

A kind of cerium-doped lutetium disilicate scintillation fiber and its electrospinning synthesis method

technical field

The invention belongs to the technical field of preparation of nano-optic functional materials, and relates to a cerium-doped lutetium disilicate scintillation fiber and a synthesis method thereof, in particular to a method for electrospinning a cerium-doped lutetium disilicate scintillation fiber.

Background technique

Cerium-doped lutetium disilicate (Lu ₂ Si ₂ O ₇ :Ce ³⁺ , abbreviated as LPS:Ce) density is about 6.2g/cm ³ , the density is relatively high, and the fluorescence decay time is short, about 30~40ns, Less than 1/7 of the scintillation single crystal BGO (BGO is an excellent scintillation single crystal, used in nuclear medicine detectors), the fluorescence emission peak is within the detection sensitivity range of the photomultiplier tube, and the effective atomic number is Z=63.8 , has good detection efficiency for γ-rays, and its energy resolution is similar to that of BGO. Moreover, cerium-doped lutetium disilicate (LPS: Ce) has excellent chemical stability and high temperature stability, no deliquescence, and high mechanical strength. Based on the above outstanding characteristics, cerium-doped lutetium disilicate (LPS:Ce) has broad application prospects in the fields of high-energy physics and nuclear medicine diagnosis (especially positron emission tomography PET), and is a promising comprehensive performance. flashing material. At present, there have been many reports on the preparation methods of cerium-doped lutetium disilicate (LPS:Ce) scintillation materials. A method for preparing cerium-doped lutetium disilicate submicron imaging fluorescent screen by sol-gel method.

Due to the unique physical and chemical effects of one-dimensional nanomaterials, including excellent mechanical properties, transport properties, quantum effects, etc., they have huge potential applications in the fields of electricity, magnetism, and optics. The scintillation properties of nano scintillation fibers will show special changes in one-dimensional scale, and the fiber materials are easy to form and assemble, and they also have great application potential in scintillation devices. Therefore, the cerium-doped lutetium disilicate scintillation fiber has greater application potential in the field of nuclear medicine diagnosis than its scintillation powder or scintillation crystal. Among many methods for preparing fibers, electrospinning is a simple and effective method for producing nanoscale fibers. It has low input cost, simple process flow, wide selection of raw materials, easy control of product morphology, structure, and composition, and can continuously prepare microfibers or nanofibers with high aspect ratios. However, there is no relevant report on the preparation of cerium-doped lutetium disilicate scintillation fibers by electrospinning technology.

Contents of the invention

The object of the present invention is to provide a cerium-doped lutetium disilicate scintillation fiber and its electrospinning synthesis method to prepare the scintillation fiber with excellent performance and great application potential in the field of scintillation materials for nuclear medicine diagnosis.

Here, the present invention provides a cerium-doped lutetium disilicate scintillation fiber, the chemical composition of the scintillation fiber is Lu ₂ Si ₂ O ₇ :Ce ³⁺ , the atomic weight percentage of Ce/Lu is 0.1%-2%; The phase structure is Lu ₂ Si ₂ O ₇ , and the fiber diameter is between 500 nanometers and 2 microns.

The aspect ratio of the scintillation fiber is 10:1˜100:1.

The cerium-doped lutetium disilicate scintillation fiber of the present invention has continuous morphology, high aspect ratio, smooth surface, and excellent scintillation performance, and has great potential in the field of scintillation materials for nuclear medicine diagnosis such as PET (Positron Emission computed Tomograph positron emission computer tomography) application potential.

In another aspect, the present invention provides a method for synthesizing the cerium-doped lutetium disilicate scintillation fiber by electrospinning, comprising: preparing a spinning stock solution containing a silicon source, a lutetium source, a cerium source and a polymer; Electrospinning the spinning stock solution to obtain a cerium-doped lutetium disilicate fiber precursor; treating the precursor at high temperature to obtain the cerium-doped lutetium disilicate scintillation fiber.

The silicon source can be ethyl orthosilicate, or known methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, etc., but in the present invention, it is preferably ethyl orthosilicate which is cheaper. The lutetium source may be lutetium oxide, lutetium chloride or its hydrate, lutetium nitrate or its hydrate, etc., but in the present invention, lutetium oxide with relatively stable properties is preferred. The cerium source may be soluble inorganic cerium salts and hydrates thereof, including cerium nitrate and hydrates thereof, cerium acetate and hydrates thereof, cerium chloride and hydrates thereof, etc., but in the present invention is preferably cerium nitrate. The high molecular polymer may be polyvinylpyrrolidone, polyacrylonitrile, polyvinyl butyral, etc., but polyvinyl butyral is preferred in the present invention.

Preferably, the preparation of the spinning stock solution includes: adding concentrated nitric acid to lutetium oxide as a source of lutetium, heating and stirring to dissolve and then evaporating the solution to obtain a white lutetium nitrate solid, then dissolving the solid in ethanol, and Add cerium nitrate as a source of cerium and polyvinyl butyral as a polymer in turn to make a transparent viscous solution A; add tetraethyl orthosilicate to the mixture of absolute ethanol and water, stir and mix evenly Prepare solution B; mix the solution A and solution B and stir to prepare the spinning dope. Wherein, the stirring time for preparing solution B is preferably 1-4 hours; the mixing and stirring time for solutions A and B is 1-2 hours. More preferably, during the preparation of solution B, ethyl orthosilicate is added to the mixture of absolute ethanol and water, and then a few drops of concentrated hydrochloric acid are added, and stirred and mixed evenly. Concentrated hydrochloric acid can promote the hydrolysis of ethyl orthosilicate. A small amount of acid not only ensures that the electrospinning cannot be caused by rapid gelation due to too much acid, but also makes the hydrolysis reaction sufficient.

During the preparation of the solution A, the mass ratio of the lutetium oxide to the concentrated nitric acid is preferably 1:3-5. The amount of the cerium source relative to the lutetium source is based on the stoichiometric ratio of Ce/Lu atomic weight percentage of 0.1% to 2%. In addition, the mass ratio of lutetium oxide to ethanol is preferably 1:3-4.

During the preparation of the solution A, the mass ratio of the polyvinyl butyral added to the ethanol in the solution A is 6%-7%.

In the preparation process of the solution B, the mass ratio of the ethyl orthosilicate, absolute ethanol, water and concentrated hydrochloric acid is preferably 5:3-7:0.5-2:0.05-0.2.

The mass ratio of ethyl orthosilicate to lutetium oxide is preferably 1:0.9˜1:1, more preferably 1:0.928.

Preferably, the electrospinning voltage is 10-20 kV, the distance between the needle and the roller is 9-15 cm, and the advancing speed of the syringe is 0.5-5 ml/h.

Also, preferably, the electrospinning receiving device is an electric drum with a rotating speed of 10 m/min, a cylinder length of 300 mm, and a diameter of 60 mm.

Preferably, the high temperature treatment refers to heat preservation at 1100-1200° C. for 4-6 hours in an air atmosphere.

The benefit and superiority of the present invention lie in that: the present invention synthesizes cerium-doped lutetium disilicate scintillation fiber by electrospinning. The fiber prepared by the method is not only continuous, has a high aspect ratio and a smooth surface, but also has simple process steps, low production cost, controllable fiber formation and excellent scintillation performance. The cerium-doped lutetium disilicate scintillation fiber prepared by the invention has great application potential in the field of scintillation materials for nuclear medicine diagnosis such as PET.

Description of drawings

Figure 1 shows Lu ₂ Si ₂ O ₇ prepared with tetraethyl orthosilicate as the silicon source, lutetium oxide as the lutetium source, cerium nitrate as the cerium source, polyvinyl butyral as the polymer, and ethanol as the solvent: X-ray diffraction (XRD) pattern of Ce ³⁺ scintillation fiber;

Fig. 2 is the PL spectrogram of Lu ₂ Si ₂ O ₇ :Ce ³⁺ (Ce/Luat%=0.5%) fiber prepared by the method of the present invention, and its emission wavelength peak is around 380nm;

Fig. 3 is the PLE spectrum of Lu ₂ Si ₂ O ₇ :Ce ³⁺ (Ce/Luat%=0.5%) fiber prepared by the method of the present invention, and its excitation wavelength has two peaks at 300nm and 350nm;

Fig. 4 is a scanning electron micrograph (4000 times) of Lu ₂ Si ₂ O ₇ :Ce ³⁺ fibers prepared by the method of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and the following specific embodiments. It should be understood that the following embodiments and/or accompanying drawings are only used to illustrate the present invention rather than limit the present invention.

Cerium-doped lutetium disilicate (LPS:Ce) has excellent chemical stability and high temperature stability, no deliquescence, and high mechanical strength. Based on the above outstanding characteristics, cerium-doped lutetium disilicate (LPS:Ce) has broad application prospects in the fields of high-energy physics and nuclear medicine diagnosis (especially positron emission tomography PET), and is a promising comprehensive performance. flashing material. The scintillation properties of nano scintillation fibers will show special changes in one-dimensional scale, and the fiber materials are easy to form and assemble, and they also have great application potential in scintillation devices. Here, the present invention provides a cerium-doped lutetium disilicate scintillation fiber, the chemical composition of which is Lu ₂ Si ₂ O ₇ :Ce ³⁺ , the atomic weight percentage of Ce/Lu is 0.1% to 2%; the crystal phase structure is Lu ₂ Si ₂ O ₇ , the fiber diameter is between 500 nm and 2 microns. Fig. 4 shows the scanning electron micrograph (4000 times) of Lu ₂ Si ₂ O ₇ : Ce ³⁺ scintillation fiber prepared by the method of the present invention, its diameter is between 500 nanometers and 2 microns, it can be seen from the figure that the present invention The Lu ₂ Si ₂ O ₇ :Ce ³⁺ scintillating fibers have continuous morphology, high aspect ratio and smooth surface.

The electrospinning method for synthesizing cerium-doped lutetium disilicate scintillation fibers of the present invention comprises: preparing a spinning stock solution containing a silicon source, a lutetium source, a cerium source and a polymer; performing electrospinning on the spinning stock solution A cerium-doped lutetium disilicate fiber precursor is obtained; the precursor is subjected to high temperature treatment to obtain the cerium-doped lutetium disilicate scintillation fiber.

More specifically, as an example, the method of the present invention includes the following steps:

(1) Weigh a certain amount of lutetium oxide, add concentrated nitric acid, heat and stir until dissolved, then evaporate the solution to obtain white lutetium nitrate solid.

(2) Add ethanol, stir and dissolve lutetium nitrate, and then add a certain amount of cerium nitrate. Then add polyvinyl butyral, stir until transparent viscous liquid.

(3) Weigh ethyl orthosilicate, add it to the mixture of absolute ethanol and water, add a few drops of concentrated hydrochloric acid, stir for 1-4 hours, and mix well.

(4) Mix the solution prepared in step (2) with the solution prepared in step (3), and stir for 1-2 hours to obtain a spinning dope.

(5) Add the prepared spinning stock solution into the syringe, adjust the spinning voltage, the syringe advancing speed parameters, the distance between the needle and the roller, and perform electrospinning to obtain the cerium-doped lutetium disilicate fiber precursor.

(6) Treating the fiber precursor in an air atmosphere at 1100-1200°C for 4h-6h to obtain the final cerium-doped lutetium disilicate fiber.

In step (1), the mass ratio of lutetium oxide to concentrated nitric acid may be 1:3-5. In addition, the mass ratio of lutetium oxide to ethanol may be 1:3-4.

In step (2), the doping concentration of cerium nitrate (Ce/Luat%) may be 0.1%-2%. The mass ratio of polyvinyl butyral to ethanol in this step is 6%-7%.

In step (3), the mass ratio of ethyl orthosilicate, absolute ethanol, water and concentrated hydrochloric acid may be 5:3-7:0.5-2:0.05-0.2. The mass ratio of ethyl orthosilicate to lutetium oxide is 1:0.9˜1:1, preferably 1:0.928.

In step (5), the electrospinning selection voltage is 10-20 kV, the distance between the needle and the drum is 9-15 cm, and the advancing speed of the syringe is 0.5-5 ml/h. The electrospinning receiving device is an electric drum with a rotating speed of 10 m/min, a cylinder length of 300 mm, and a diameter of 60 mm. The needle size of the syringe can be selected from No. 5, No. 6 and No. 7 needles, and the inner diameters are respectively 0.26, 0.34 and 0.51 mm.

Examples are given below to describe the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention, and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above contents of the present invention all belong to the present invention scope of protection. The specific quality, reaction time and temperature, process parameters, etc. of the following examples are only an example of a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the examples below specific value.

Example 1

(1) Weigh 4.64g of lutetium oxide, add 20g of concentrated nitric acid, heat and stir until dissolved, then evaporate the solution to obtain white solid lutetium nitrate; (2) add 20g of ethanol, stir and dissolve the solid lutetium nitrate, and then add 0.1012g of cerium nitrate, then add 1.2g of polyvinyl butyral, and stir until a transparent viscous liquid; (3) Weigh 5g of tetraethyl orthosilicate, add it to the mixed solution of 5g of absolute ethanol and 1g of water, Then add 0.1g of concentrated hydrochloric acid, stir for 4 hours, and mix well; (4) combine the steps

(2) The prepared solution is mixed with the solution prepared in step (3), and after stirring for 1 hour, the spinning source solution is obtained; (5) The prepared spinning stock solution is added to the syringe, and the spinning voltage is adjusted to 10kV, The injection speed parameter is 0.5ml/h, the needle is No. 6 needle, the receiving device is a roller, the roller speed is 10m/min, the length of the cylinder is 300mm, the diameter is 60mm, the distance between the needle and the roller is controlled at 9cm, and electrospinning is carried out to obtain the mixed Cerium disilicate lutetium fiber precursor; (6) The spinning precursor was treated in air atmosphere at 1200°C for 4 hours to obtain the final cerium-doped lutetium disilicate fiber. The crystal phase structure of the prepared cerium-doped lutetium disilicate fiber was detected by X-ray diffractometer, and the X-ray diffraction diagram is shown in Figure 1. From Figure 1, it can be known that the phase of the prepared material is Lu ₂ Si ₂ O ₇ . The corresponding curves in Fig. 2 and Fig. 3 are the PL emission spectrum and PLE excitation spectrum of the Lu ₂ Si ₂ O ₇ :Ce ³⁺ (Ce/Luat%=0.5%) fiber of this embodiment, respectively. Its morphology was observed with a scanning electron microscope, and the scanning electron microscope photos are shown in Figure 4. It can be seen from Figure 4 that the prepared product is a fiber with a diameter between 500 nanometers and 2 micrometers, a high aspect ratio and a smooth surface.

Example 2

(1) Weigh 4.64g of lutetium oxide, add 18g of concentrated nitric acid, heat and stir until dissolved, then evaporate the solution to obtain white solid lutetium nitrate; (2) add 10g of ethanol, stir and dissolve the solid lutetium nitrate, and then add 0.2024g of cerium nitrate, then add 0.8g of polyvinyl butyral, and stir until a transparent viscous liquid; (3) Weigh 5g of tetraethyl orthosilicate, add it to the mixed solution of 5g of absolute ethanol and 1g of water, Then add 0.1g of concentrated hydrochloric acid, stir for 4 hours, and mix well; (4) Mix the solution prepared in step (2) with the solution prepared in step (3), and stir for 1 hour to obtain the spinning source solution; (5) Mix The prepared spinning stock solution is added to the syringe, the spinning voltage is adjusted to be 20kV, the injection speed parameter is 2ml/h, the needle is No. 5 needle, the receiving device is a drum, the drum speed is 10m/min, the cylinder length is 300mm, the diameter 60mm, the distance between the needle and the drum is controlled at 12cm, and electrospinning is performed to obtain the precursor of cerium-doped lutetium disilicate fiber; (6) The spinning precursor is treated at 1200°C for 6 hours in an air atmosphere to obtain the final cerium-doped coke Lutetium fiber.

Industrial applicability: The equipment used in the present invention is simple, the preparation cost is low, the fiber composition is adjustable, the preparation conditions are mild and controllable, and the product has excellent scintillation performance. The prepared cerium-doped lutetium disilicate fiber has a smooth surface, a high aspect ratio, and a diameter of 500 nm to 2 microns. great application potential.

Claims (7)

1. a method for cerium lutetium pyrosilicate scintillating fiber is mixed in electrostatic spinning synthesis, and it is characterized in that, the chemical composition of described scintillating fiber is Lu ₂si ₂o ₇: Ce ³⁺, the atomic weight percentage of Ce/Lu is 0.1% ~ 2%; Crystal phase structure is Lu ₂si ₂o ₇, fibre diameter is between 500 nanometers to 2 micron, and described method comprises, the spinning solution of preparation containing silicon source, lutetium source, cerium source and high molecular polymer; Described spinning solution is carried out electrostatic spinning is obtained mixes cerium lutetium pyrosilicate Precursors of Fibers; Cerium lutetium pyrosilicate scintillating fiber is mixed described in being obtained through high-temperature process by described presoma;

The preparation of described spinning solution comprises: add in the luteium oxide as lutetium source red fuming nitric acid (RFNA), heating stirring and dissolving again evaporate to dryness solution obtain white lutecium nitrate solid, then by described dissolution of solid in ethanol, and add the cerous nitrate as cerium source successively and the polyvinyl butyral resin as high molecular polymer makes clear viscous solution A; Ethyl orthosilicate is joined in the mixed liquor of absolute ethyl alcohol and water, then add a small amount of concentrated hydrochloric acid, be uniformly mixed obtained solution B; Mix described solution A and solution B is uniformly mixed obtained described spinning solution; Described in the preparation process of described solution B, the mass ratio of ethyl orthosilicate, absolute ethyl alcohol, water and concentrated hydrochloric acid is 5:3 ~ 7:0.5 ~ 2:0.05 ~ 0.2.

2. method according to claim 1, is characterized in that, described scintillating fiber draw ratio is 10:1 ~ 100:1.

3. method according to claim 1, is characterized in that the mass ratio of ethanol in described polyvinyl butyral resin and solution A is 6% ~ 7%.

4. according to the method in any one of claims 1 to 3, it is characterized in that, the mass ratio of described ethyl orthosilicate and luteium oxide is 1:0.9 ~ 1:1.

5. according to the method in any one of claims 1 to 3, it is characterized in that described electrostatic spinning selects voltage to be 10 ~ 20kV, syringe needle and cylinder distance are 9 ~ 15cm, and syringe fltting speed is 0.5 ~ 5ml/h.

6. according to the method in any one of claims 1 to 3, it is characterized in that described electrostatic spinning receiving system is motorized pulleys, rotating speed 10m/min, barrel lenght 300mm, diameter 60mm.

7. according to the method in any one of claims 1 to 3, it is characterized in that described high-temperature process refers to that 1100 ~ 1200 DEG C are incubated 4 ~ 6 hours in air atmosphere.