Thermoluminescent film for cumulative X-ray dosimeter as well as preparation method and application of thermoluminescent film

Abstract

The invention provides a thermoluminescent film for a cumulative X-ray dosimeter as well as a preparation method and application of the thermoluminescent film. The preparation method comprises the following steps: preparing powder C by taking NH4F, NaF, Lu (NO3) 36H2O and Tb (NO3) 36H2O as raw materials; the powder C is subjected to an induction heating-stirring reaction, and after the reaction is finished, rare earth fluoride D is obtained; adding rare earth fluoride D and PMMA particles into an ethanol solution, transferring the obtained mixed solution into a dichloromethane solution, and continuously stirring to form a mixed solution E; weighing a polydimethylsiloxane prepolymer and a curing agent, then adding a dichloromethane solution, and carrying out ultrasonic treatment to form a uniform dispersion F; under a normal-temperature stirring condition, adding the dispersion F into the mixed solution E to obtain a gelatinous mixture G; transferring the gelatinous mixture G to a pretreated substrate, blade-coating the substrate with the gelatinous mixture G, heating and annealing, cooling to room temperature, and taking down the film to obtain the thermoluminescent film for the cumulative X-ray dosimeter.

Description

Technical Field

[0001] This invention belongs to the field of radiation dosimeter sensing, specifically relating to a thermoluminescent thin film for a cumulative X-ray dosimeter, its preparation method, and its application. Background Technology

[0002] In fields involving ionizing radiation, such as nuclear energy, nuclear medicine, industrial flaw detection, radiotherapy, and aerospace, accurate monitoring of ionizing radiation doses received by personnel and the environment is crucial for ensuring safety. Cumulative dose monitoring is particularly critical, reflecting the total radiation exposure over a specific period and providing direct evidence for radiation protection measures, health risk assessments, and early warnings. Currently, thermoluminescent dosimeters, with their advantages of high sensitivity, wide measurement range, small size, reusability, and support for passive and integrating measurements, are widely used for personal and environmental cumulative dose monitoring. As the core detection element of this dosimeter, the performance of the thermoluminescent material directly determines the measurement accuracy, data reliability, and scenario adaptability of the entire monitoring system in practical applications.

[0003] Currently, the thermoluminescent materials commonly used in traditional cumulative dose monitoring technology mainly include LiF:Mg,Ti, CaSO4:Dy / Tm, CaF2:Mn, and Al2O3:C. However, these materials have many inherent limitations in practical applications: LiF:Mg,Ti, as one of the most widely used materials, has an effective atomic number similar to that of human tissue and low energy dependence, but suffers from complex preparation processes, low sensitivity, and significant signal decay effects; CaSO4:Dy / Tm and CaF2:Mn, although highly sensitive, have effective atomic numbers much higher than those of human tissue, resulting in a significantly enhanced response to low-energy X / γ rays and poor energy dependence, requiring the addition of metal filters for energy compensation, thus increasing the complexity of the dosimeter structure; Al2O3:C has high sensitivity, but is susceptible to photoluminescence and thermal instability, and its signal decays under light or room temperature conditions, thus requiring extremely strict storage conditions and pre-readout operation, which to some extent limits the reliability and applicability of its measurement results. Therefore, there is an urgent need to develop novel thermoluminescent materials to construct cumulative X-ray dosimeters with high sensitivity and stability. Furthermore, exploring their integrated applications in intelligent monitoring systems also holds significant research value and broad application prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a thermoluminescent thin film for a cumulative X-ray dosimeter, its preparation method, and its application, in order to overcome the shortcomings of the existing technology. The flexible thermoluminescent thin film prepared by this invention, when applied to a cumulative X-ray dosimeter, not only has the advantage of high sensitivity, but also has the advantages of high stability, simple process, non-toxicity and pollution-free, and low cost.

[0005] This invention is achieved through the following technical solution: A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter includes the following steps: 1) Add NH4F, NaF, and Lu(NO3)3 to solution A. 6H2O and Tb(NO3)3 The mixture was subjected to ultrasonic vibration grinding in a 6H2O mixture to obtain a milky white viscous mixture B, which was then dried by infrared radiation to obtain powder C. 2) Powder C was subjected to induction heating and stirring reaction. The temperature was increased from room temperature to a preset temperature at a preset induction frequency and held. After the reaction was completed, the product was washed with ethanol and deionized water, centrifuged and dried to obtain rare earth fluoride D. 3) Add rare earth fluoride D and PMMA particles to an ethanol solution and stir at room temperature to obtain a uniformly dispersed mixed solution. Transfer the mixed solution to a dichloromethane solution and continue stirring to form a mixed solution E. Weigh out polydimethylsiloxane prepolymer and curing agent, then add them to a dichloromethane solution and sonicate to form a uniformly dispersed body F. 4) Under normal temperature stirring conditions, the dispersion F is slowly added to the mixed solution E at a volume ratio of 2:1, and the mixture is reacted under vacuum for 60~120 min to obtain a gel-like mixture G; 5) Transfer the gel mixture G to the pretreated substrate, coat the gel mixture G onto the substrate, heat and anneal, and after cooling to room temperature, remove the film to obtain NaLuF4:Tb@PDMS flexible thermoluminescent film, i.e. thermoluminescent film for cumulative X-ray dosimeter.

[0006] Furthermore, the NH4F, NaF, and Lu(NO3)3 added in step 1) 6H2O and Tb(NO3)3 The molar ratio of 6H2O is (90~110):(40~60):(14~20):(1~7); Solution A is any one of anhydrous ethanol, acetone, isopropanol and ethyl acetate; the ratio between solution A and NaF powder is (1~5) mL:0.1 g; the ultrasonic vibration frequency is 40~80 kHz, the grinding time is 3~9 min; the infrared drying time is 10~50 min.

[0007] Further, step 2) specifically involves: transferring white powder C into an induction heating-stirring vessel, adding carbon balls as an induction source, moving the induction heating-stirring vessel into an induction heating-stirring device, raising the temperature from room temperature to a preset temperature at a preset induction frequency and holding it at that temperature, then removing the carbon balls, washing them sequentially with ethanol and deionized water, centrifuging them, and drying the product to obtain rare earth fluoride D. The carbon balls have a diameter of 1 cm, and the stirring speed is 200~400 rpm. The induction heating-stirring equipment heats the temperature from room temperature to 200-500 ℃ at an induction frequency of 400-600 KHz and holds the temperature for 1-3 hours.

[0008] Further, in step 3), the PMMA particles added have a particle size of 2-6 mm, and the mass ratio of rare earth fluoride D to PMMA particles is 1:2. 0.5-3 g of the mixture of PMMA particles and rare earth fluoride D is added to every 5 mL of ethanol solution, and the mixture is stirred at 300-500 rpm for 5-15 min at room temperature to ensure thorough pre-dispersion. Then, the pre-dispersed solution is transferred to a dichloromethane solution with an equal volume to the ethanol solution using a dropper, and stirred at 300-500 rpm for 5-15 min at room temperature to obtain a uniformly dispersed mixed solution.

[0009] Further, in step 3), the mass ratio of dimethylsiloxane prepolymer to curing agent is (8~15):1. 1~10 g of the mixture of dimethylsiloxane prepolymer and curing agent is added to every 5 mL of dichloromethane solution, and a uniform dispersion F is formed under ultrasonic frequency conditions of 40~100 kHz.

[0010] Furthermore, in step 5), the substrate is a glass plate, and the pretreatment process is as follows: the glass plate is washed with water, ethanol, and acetone in sequence, and then dried.

[0011] Furthermore, in step 5), during the process of coating the gel-like mixture G onto the substrate, the squeegee height is 100~1000 μm and the coating speed is 1~3 m / min; The annealing temperature is 100~200 °C, and the annealing time is 30~90 min.

[0012] A thermoluminescent thin film for a cumulative X-ray dosimeter is prepared using the above-described method.

[0013] An application of a thermoluminescent thin film for a cumulative X-ray dosimeter in an intelligent monitoring system, the intelligent monitoring system being used for cumulative X-ray dose measurement.

[0014] Furthermore, the intelligent monitoring system includes photoelectric sensing elements, a thermoluminescent thin film, a hot stage, and terminal equipment. In use, the thermoluminescent thin film storing the accumulated dose is placed on the hot stage, and the dose is measured at 1 K·s. -1 The temperature is increased to 360 K and held at 360 K for 200 s. During this period, the light signal emitted by the thermoluminescent film is collected by a photoelectric sensing element and then wirelessly transmitted to a terminal device to display spectral information and cumulative dose values.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: 1. This invention proposes using rare earth fluorides NaLuF4:Tb 3+ Rare earth fluorides are used as thermoluminescent materials in X-ray dosimeters. Their low phonon energy characteristics effectively suppress non-radiative relaxation processes, allowing energy from radiation-trapped centers to be released more easily through radiation channels, thus significantly improving thermoluminescence efficiency. Furthermore, rare earth ions (Tb)... 3+ It serves as an ideal luminescent center within the matrix. When the material is irradiated with X-rays, the resulting electron-hole pairs are trapped by the trap center; during thermal excitation, the electrons are released and move to Tb. 3+ At this point, Tb is made possible through energy transfer or direct recombination. 3+ In the excited state ( 5 D4). Subsequently, through 5 D4 to 7 F j Energy level transitions enable highly efficient energy conversion. This efficient trap-transfer-emission mechanism gives the material a good trap structure, moderate thermoluminescence readout temperature, high sensitivity, and excellent dose linearity response, meeting the core performance requirements of cumulative X-ray dose detection. Meanwhile, rare-earth fluorides possess high chemical stability and high effective atomic numbers, which enhance the absorption capacity for high-energy radiation, thus improving the dose response intensity from a mechanistic perspective. Furthermore, their strong ionicity and stable band structure make the material easy to dopant and form controllable trap depths, thereby further adjusting the thermoluminescence peak position and readout window, making the overall performance more designable. Further, this material was composited with PDMS to prepare NaLuF4:Tb³. + @PDMS flexible thermoluminescent films can be closely adhered to complex curved surfaces, significantly expanding their application potential on uneven surfaces. The preparation process is simple to operate, with mild reaction conditions, high repeatability, non-toxicity and pollution-free, and the raw materials are widely available, giving it a significant resource and cost advantage.

[0016] 2. This invention proposes a PMMA-assisted powder dispersion method, which disperses powders in NaLuF4:Tb³ + PMMA particles are introduced into an ethanol solution of powder, and magnetic stirring is used to move the PMMA particles, achieving efficient grinding and uniform dispersion of the powder. This method can effectively reduce the powder particle size and avoid the sedimentation problem of large particles during film formation, providing a uniform and stable powder dispersion system for the preparation of high-quality flexible thin-film dosimeters.

[0017] 3. This invention uses NaLuF4:Tb³ +The PDMS flexible film is integrated into a self-built intelligent monitoring system for monitoring the cumulative X-ray dose in the environment. It exhibits good linear dose response in the test. The monitoring data can be wirelessly transmitted to the terminal device via WiFi module, realizing remote and flexible monitoring of radiation dose. It provides a new intelligent solution for environmental radiation protection and has good industrialization prospects. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. The following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 XRD pattern of the NaLuF4:Tb@PDMS flexible thermoluminescent film prepared in Example 1; Figure 2 XRD pattern of the NaLuF4:Tb@PDMS flexible thermoluminescent film prepared in Example 2; Figure 3 XRD pattern of the NaLuF4:Tb@PDMS flexible thermoluminescent film prepared in Example 3; Figure 4 The images show the radioluminescence of the NaLuF4:Tb@PDMS flexible thermoluminescent films prepared in Examples 1-3 under X-ray irradiation. Figure 5 Thermoluminescence curves of the NaLuF4:Tb@PDMS flexible thermoluminescent films prepared in Examples 1-3 are shown. Figure 6 The images show the flexible luminescence of the NaLuF4:Tb@PDMS flexible thermoluminescent films prepared in Examples 1-3 under 365nm ultraviolet irradiation. Figure 7 Cyclic stress-strain diagram of the NaLuF4:Tb@PDMS flexible thermoluminescent film prepared in Example 2; Figure 8 A comparison of dose response curves between the NaLuF4:Tb powder prepared in Example 2 and the commercially available LiF:Mg, Cu, P (GR-200A) dosing tablets; Figure 9(a) is a model scheme diagram of the intelligent monitoring system constructed in Example 2 for monitoring the cumulative X-ray dose level; Figure 9(b) shows the linear relationship between cumulative dose and thermoluminescence integral intensity obtained using the intelligent monitoring system in Example 2. Detailed Implementation

[0020] The present invention will now be described in detail: A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter includes the following steps: 1) High-purity NH4F, NaF, and Lu(NO3)3 6H2O and Tb(NO3)3 6H2O was added to an ultrasonic vibrating mill, and then solution A was added to it and ultrasonically vibrated and ground thoroughly to obtain a milky white viscous mixture B, which was then dried by infrared to obtain powder C. Among them, NH4F, NaF, and Lu(NO3)3 were added. 6H2O and Tb(NO3)3 The molar ratio of 6H2O is (90~110):(40~60):(14~20):(1~7); Solution A is any one of anhydrous ethanol, acetone, isopropanol and ethyl acetate; the ratio between solution A and NaF powder is (1~5) mL:0.1 g; the ultrasonic vibration frequency is 40~80 kHz, the grinding time is 3~9 min; the infrared drying time is 10~50 min.

[0021] 2) Transfer powder C to an induction heating-stirring vessel and add carbon balls as an induction source. Move the induction heating-stirring vessel into an induction heating-stirring device and heat it from room temperature to a preset temperature at a preset induction frequency and keep it at the preset temperature. Then take out the carbon balls, wash them with ethanol and deionized water in sequence, centrifuge and dry the product to obtain rare earth fluoride D. The carbon balls are 1 cm in diameter and the stirring speed is 200-400 rpm. The induction heating-stirring equipment heats the temperature from room temperature to 200-500 °C at an induction frequency of 400-600 kHz and holds the temperature for 1-3 hours.

[0022] 3) Add rare earth fluoride D and PMMA particles to an ethanol solution and stir at room temperature to obtain a uniformly dispersed mixed solution. Then, use a dropper with a 1 mm inner diameter tip to transfer the mixed solution to a dichloromethane solution and continue stirring to form a mixed solution E. Weigh out polydimethylsiloxane (PDMS) prepolymer and curing agent, and then add them to a dichloromethane solution and sonicate to form a uniformly dispersed body F. The PMMA particles added had a particle size of 2-6 mm, and the mass ratio of rare earth fluoride D to PMMA was 1:2. 0.5-3 g of the PMMA particle and rare earth fluoride D mixture was added to every 5 mL of ethanol solution, and the mixture was stirred at 300-500 rpm for 5-15 minutes to ensure thorough pre-dispersion. The pre-dispersed solution was then transferred dropwise to a dichloromethane solution with an equal volume to the ethanol solution, and stirred at 300-500 rpm for 5-15 minutes at room temperature to obtain a uniformly dispersed mixed solution. The mass ratio of dimethylsiloxane (PDMS) prepolymer to curing agent is (8~15):1. 1~10 g of the mixture of dimethylsiloxane (PDMS) prepolymer and curing agent is added to every 5 mL of dichloromethane solution, and a uniform dispersion F is formed under ultrasonic frequency conditions of 40~100 kHz.

[0023] 4) Transfer the mixed solution E to a two-necked flask, and slowly add the dispersion F to the mixed solution E at a volume ratio of 2:1 while stirring at room temperature. Then, connect the two-necked flask to a vacuum pump and vacuum treat for 60-120 min to obtain a gel-like mixture G in the flask.

[0024] 5) Transfer the gel mixture G to the pretreated substrate, quickly apply the gel mixture G to the substrate by electric scraping, heat and anneal, cool to room temperature and peel off the film to obtain NaLuF4:Tb@PDMS flexible thermoluminescent film.

[0025] The scraper height is 100~1000 μm, the scraping speed is 1~3 m / min, the annealing temperature is 100~200 °C, and the annealing time is 30~90 min.

[0026] The present invention also provides a thermoluminescent thin film for a cumulative X-ray dosimeter, which is prepared by the above-described preparation method.

[0027] This invention also provides an application of a thermoluminescent thin film for a cumulative X-ray dosimeter in an intelligent monitoring system. The intelligent monitoring system is used for cumulative X-ray dose measurement and includes photoelectric sensing elements (CCD linear array, digital camera, photoresistor), a thermoluminescent thin film, a hot stage, and terminal equipment. During X-ray leakage, the thermoluminescent thin film interacts with the X-rays and stores the cumulative dose of ionizing radiation within it. Therefore, when using this system, the thermoluminescent thin film storing the cumulative dose needs to be placed on the hot stage, and the dose measured at 1 K·s... -1 The temperature is increased to 360 K and held at 360 K for 200 s. During this period, the photoelectric sensing element can collect the light signal emitted by the thermoluminescent film, and then wirelessly transmit the light signal to the terminal device via the WiFi module to display spectral information and cumulative dose values.

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the methods and experimental equipment used in the following embodiments are conventional methods and instruments.

[0029] Example 1 A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter includes the following steps: 1) High-purity NH4F, NaF, and Lu(NO3)3 6H2O and Tb(NO3)3 6H2O was added to an ultrasonic vibrating mill in a molar ratio of 90:40:14:1, and then acetone was added to it in a ratio of 1 mL to 0.1 g of NaF powder. The mixture was then ground thoroughly at an ultrasonic vibration frequency of 40 kHz for 3 min to obtain a milky white viscous mixture B. After infrared drying for 10 min, a white powder C was obtained. 2) Transfer white powder C to an induction heating-stirring vessel and add carbon balls with a diameter of 1 cm as an induction source. Move the induction heating-stirring vessel into an induction heating-stirring device and heat it from room temperature to 200 °C at an induction frequency of 400 kHz and keep it at that temperature for 1 h. Set the stirring speed to 200 rpm. Then remove the carbon balls, wash them with ethanol and deionized water in sequence, centrifuge and dry the product to obtain rare earth fluoride D. 3) Add rare earth fluoride D and PMMA particles with a particle size of 2 mm to an ethanol solution at a mass ratio of 1:2. Add 0.5 g of the PMMA particle and rare earth fluoride D mixture to every 5 mL of ethanol solution. Stir at 300 rpm for 5 min to obtain a uniformly dispersed mixed solution. Then, use a dropper with a 1 mm inner diameter to transfer the mixed solution to a dichloromethane solution with the same volume as the ethanol solution. Continue stirring at 300 rpm for 5 min to form a mixed solution E. Weigh polydimethylsiloxane (PDMS) prepolymer and curing agent at a mass ratio of 8:1. Add 1 g of the PDMS and curing agent mixture to every 5 mL of dichloromethane. Sonicate at 40 kHz to form a uniformly dispersed body F. 4) Transfer the mixed solution E to a two-necked flask. Under stirring at room temperature, slowly add the dispersion F to the mixed solution E at a volume ratio of 2:1 to ensure thorough mixing. Then, connect the two-necked flask to a vacuum pump and vacuum treat for 60 min. A gel-like mixture G is obtained in the flask.

[0030] 5) The gel-like mixture G was transferred to a glass substrate that had been sequentially cleaned and dried with water, ethanol, and acetone. Using a 100 μm high electric doctor blade, the gel-like mixture G was rapidly coated at a speed of 1 m / min. The substrate was then heated and annealed at 100 °C for 30 min. After cooling to room temperature, the film was peeled off to obtain a NaLuF4:Tb@PDMS flexible thermoluminescent film. Finally, this flexible thermoluminescent film was integrated with a digital camera, a hot stage, and terminal equipment to obtain a cumulative radiation dose intelligent monitoring system. The monitoring process is as follows: The thermoluminescent film storing the cumulative dose was placed on the hot stage, and the dose was measured at 1 K·s. -1 The temperature is increased to 360K and held at 360K for 200 seconds. During this time, a digital camera can capture the light signal emitted by the thermoluminescent film, which is then wirelessly transmitted to a terminal device via a WiFi module to display spectral information and cumulative dose values.

[0031] Example 2 A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter includes the following steps: 1) High-purity NH4F, NaF, and Lu(NO3)3 6H2O and Tb(NO3)3 6H2O was added to an ultrasonic vibrating mill in a molar ratio of 100:50:17:3. Anhydrous ethanol was then added to the mill in a ratio of 3 mL to 0.1 g of NaF powder. The mixture was then ground thoroughly at an ultrasonic vibration frequency of 60 kHz for 6 min to obtain a milky white viscous mixture B. After infrared drying for 30 min, a white powder C was obtained. 2) Transfer white powder C to an induction heating-stirring vessel and add carbon balls with a diameter of 1 cm as an induction source. Move the induction heating-stirring vessel into an induction heating-stirring device and heat it from room temperature to 350 °C at an induction frequency of 500 KHz and keep it at that temperature for 2 h. Set the stirring speed to 300 rpm. Then remove the carbon balls, wash them with ethanol and deionized water in sequence, centrifuge and dry the product to obtain rare earth fluoride D. 3) Rare earth fluoride D and PMMA particles with a particle size of 4 mm were added to an ethanol solution at a mass ratio of 1:2. 1.5 g of the PMMA particle and rare earth fluoride D mixture was added to every 5 mL of ethanol solution. The mixture was stirred at 400 rpm for 10 min to obtain a uniformly dispersed solution. The solution was then transferred to a dichloromethane solution with the same volume as the ethanol solution using a dropper with a 1 mm inner diameter tip. The mixture was stirred at 400 rpm for 10 min to form a mixed solution E. Polydimethylsiloxane (PDMS) prepolymer and curing agent were weighed at a mass ratio of 10:1. 5 g of the PDMS and curing agent mixture was added to every 5 mL of dichloromethane solution. The mixture was ultrasonically treated at 60 kHz to form a uniformly dispersed body F. 4) Transfer the mixed solution E to a two-necked flask. Under stirring at room temperature, slowly add the dispersion F to the mixed solution E at a volume ratio of 2:1 to ensure thorough mixing. Then, connect the two-necked flask to a vacuum pump and vacuum treat for 90 min. A gel-like mixture G is obtained in the flask.

[0032] 5) The gel-like mixture G was transferred to a glass substrate that had been sequentially cleaned and dried with water, ethanol, and acetone. Using a 500 μm high electric doctor blade, G was rapidly electric-coated at a speed of 2 m / min. The substrate was then annealed at 150 °C for 60 min. After cooling to room temperature, the film was peeled off to obtain a NaLuF4:Tb@PDMS flexible thermoluminescent film. Finally, this flexible thermoluminescent film was integrated with a CCD linear array, a hot stage, and a terminal device to obtain a cumulative radiation dose intelligent monitoring system. The monitoring process is as follows: The thermoluminescent film storing the cumulative dose was placed on the hot stage, and the dose was measured at 1 K·s. -1 The temperature is increased to 360 K and held at 360 K for 200 s. During this period, the CCD linear array can collect the light signal emitted by the thermoluminescent film, and then wirelessly transmit the light signal to the terminal device via the WiFi module to display spectral information and cumulative dose values.

[0033] Example 3 A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter includes the following steps: 1) High-purity NH4F, NaF, and Lu(NO3)3 6H2O and Tb(NO3)3 6H2O was added to an ultrasonic vibrating mill in a molar ratio of 110:60:20:7. Ethyl acetate was then added to the mill in a ratio of 5 mL to 0.1 g of NaF powder. The mixture was then ground thoroughly at an ultrasonic vibration frequency of 80 kHz for 9 min to obtain a milky white viscous mixture B. After infrared drying for 50 min, a white powder C was obtained. 2) Transfer white powder C to an induction heating-stirring vessel and add carbon balls with a diameter of 1 cm as an induction source. Move the induction heating-stirring vessel into an induction heating-stirring device and heat it from room temperature to 500 °C at an induction frequency of 600 kHz and keep it at that temperature for 3 h. Set the stirring speed to 400 rpm. Then remove the carbon balls, wash them with ethanol and deionized water in sequence, centrifuge and dry the product to obtain rare earth fluoride D. 3) Add rare earth fluoride D and 6 mm PMMA particles to an ethanol solution at a mass ratio of 1:2. Add 3 g of the PMMA particle and rare earth fluoride D mixture to every 5 mL of ethanol solution. Stir at 500 rpm for 15 min to obtain a uniformly dispersed mixed solution. Then, use a dropper with a 1 mm inner diameter to transfer the mixed solution to a dichloromethane solution of the same volume as the ethanol solution and continue stirring at 500 rpm for 15 min to form mixed solution E. Weigh polydimethylsiloxane (PDMS) prepolymer and curing agent at a mass ratio of 15:1. Add 10 g of the PDMS and curing agent mixture to every 5 mL of dichloromethane. Sonicate at 100 kHz to form a uniformly dispersed body F. 4) Transfer the mixed solution E to a two-necked flask. Under stirring at room temperature, slowly add the dispersion F to the mixed solution E at a volume ratio of 2:1 to ensure thorough mixing. Then, connect the two-necked flask to a vacuum pump and vacuum treat for 120 min. A gel-like mixture G is obtained in the flask.

[0034] 5) The gel-like mixture G was transferred to a glass substrate that had been sequentially cleaned and dried with water, ethanol, and acetone. Using a 1000 μm high electric doctor blade, the gel-like mixture G was rapidly coated at a speed of 3 m / min. The substrate was then annealed at 200 °C for 90 min. After cooling to room temperature, the film was peeled off to obtain a NaLuF4:Tb@PDMS flexible thermoluminescent film. Finally, this flexible thermoluminescent film was integrated with a photoresistor, a hot stage, and a terminal device to obtain a cumulative radiation dose intelligent monitoring system. The monitoring process is as follows: The thermoluminescent film storing the cumulative dose was placed on the hot stage, and the dose was measured at 1 K·s. -1 The temperature is increased to 360K and held at 360K for 200 s. During this time, a photoresistor collects the light signal emitted by the thermoluminescent film, which is then wirelessly transmitted to a terminal device via a WiFi module to display spectral information and cumulative dose values.

[0035] Depend on Figure 1-3 The XRD patterns show that the X-ray diffraction peaks of the NaLuF4:Tb@PDMS thermoluminescent films in Examples 1-3 correspond to the standard card of NaLuF4 and are relatively sharp, indicating that the samples have high purity and crystallinity. Figure 4The radiation emission spectra show that the NaLuF4:Tb@PDMS thermoluminescent films in Examples 1-3 emit Tb 3+ The characteristic emission spectrum of Example 2 is shown, and the radiative emission intensity of Example 2 is higher than that of Examples 1 and 3. Figure 5 The thermoluminescent spectra show that the NaLuF4:Tb@PDMS thermoluminescent films in Examples 1-3 exhibit significant thermoluminescent signals, and the thermoluminescence intensity of Example 2 is higher than that of Examples 1 and 3. Figure 6 As can be seen from the flexible emission patterns, the NaLuF4:Tb@PDMS thermoluminescent films in Examples 1-3 exhibit flexibility. Considering the excellent radiative emission and thermoluminescence properties of Example 2, the following tests focus on Example 2. Figure 7 As can be seen from the cyclic stress-strain diagram, the NaLuF4:Tb@PDMS flexible thermoluminescent film in Example 2 has excellent flexibility. Figure 8 Figure 9(a) shows a comparison of the dose response curves of NaLuF4:Tb powder and commercially available LiF:Mg, Cu, P (GR-200A) dosimeters. The sensitivity of NaLuF4:Tb powder is 14 times that of commercially available LiF:Mg, Cu, P (GR-200A) dosimeters. Figure 9(a) shows the model scheme of the intelligent monitoring system constructed in Example 2 for monitoring the cumulative X-ray dose level. Figure 9(b) shows the linear relationship between the cumulative dose and the thermoluminescent integral intensity obtained using the intelligent monitoring system. The goodness of fit between them is 99.8%, indicating that the flexible thermoluminescent film has an excellent linear response to the cumulative dose.

[0036] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for producing a thermoluminescence film for an accumulated X-ray dosimeter, characterized by, Comprising the following steps: 1) Solution A was added to a mixture of NH4F, NaF, Lu(NO3)3 6H2O and Tb(NO3)3 6H2O and was ultrasonically vibrated and ground to obtain a milky white viscous mixture B, which was dried by infrared to obtain powder C; 2) Induction heating-stirring reaction of the powder C, heating from room temperature to a preset temperature at a preset induction frequency and holding, after the reaction, washing, centrifuging and drying the product successively with ethanol and deionized water to obtain rare earth fluoride D; 3) Adding the rare earth fluoride D and PMMA particles to an ethanol solution, stirring at room temperature to obtain a uniformly dispersed mixed solution, transferring the mixed solution to a dichloromethane solution for continuous stirring to form a mixed solution E; weighing the polydimethylsiloxane prepolymer and the curing agent, then adding the dichloromethane solution for ultrasonic treatment to form a uniformly dispersed body F; 4) Under the condition of stirring at room temperature, slowly adding the dispersed body F to the mixed solution E at a volume ratio of 2:1, and reacting for 60-120 min under vacuum to obtain a gel-like mixture G; 5) Transferring the gel-like mixture G to a pretreated substrate, coating the gel-like mixture G on the substrate, and then heating and annealing, and after cooling to room temperature, removing the film to obtain a NaLuF4:Tb@PDMS flexible thermoluminescence film, i.e. a thermoluminescence film for cumulative X-ray dosimeter.

2. The method for preparing a thermoluminescent film for an integrated X-ray dosimeter according to claim 1, characterized in that, NH4F, NaF, Lu(NO3)3 6H2O and Tb(NO3)3 The molar ratio of the NH4F, NaF, Lu(NO3)3 6H2O is (90-110):(40-60):(14-20):(1-7); the solution A is any one of anhydrous ethanol, acetone, isopropyl alcohol and ethyl acetate; the ratio between the solution A and the NaF powder is (1-5) mL:0.1 g; the ultrasonic vibration frequency is 40-80 kHz, and the grinding time is 3-9 min; the infrared drying time is 10-50 min.

3. The method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter according to claim 1, characterized in that, Step 2) is specifically: transferring the white powder C into an induction heating-stirring kettle, adding carbon balls as an induction source, moving the induction heating-stirring kettle into an induction heating-stirring device, heating from room temperature to a preset temperature at a preset induction frequency and holding, then taking out the carbon balls, and washing, centrifuging and drying the product successively with ethanol and deionized water to obtain rare earth fluoride D; wherein the diameter of the carbon ball is 1 cm, and the stirring speed is 200-400 rpm; The induction heating-stirring device is heated from room temperature to 200-500 °C at an induction frequency of 400-600 KHz, and is held for 1-3 h.

4. A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter according to claim 1, characterized in that, In step 3), the particle size of the PMMA particles added is 2-6 mm, and the mass ratio of the rare earth fluoride D to the PMMA particles is 1:2; 0.5-3 g of the mixture of the PMMA particles and the rare earth fluoride D is added to every 5 mL of the ethanol solution, and the pre-dispersed solution is transferred to a dichloromethane solution with the same volume as the ethanol solution, and is continuously stirred at a speed of 300-500 rpm at room temperature for 5-15 min to obtain a uniformly dispersed mixed solution.

5. A method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter according to claim 1, characterized in that, In step 3), the mass ratio of the dimethylsiloxane prepolymer to the curing agent is (8-15):1, and 1-10 g of the mixture of the dimethylsiloxane prepolymer and the curing agent is added to every 5 mL of the dichloromethane solution to form a uniformly dispersed body F under the condition of an ultrasonic frequency of 40-100 kHz.

6. The method for preparing a thermoluminescent thin film for a cumulative X-ray dosimeter according to claim 1, characterized in that, In step 5), the substrate is a glass plate, and the pretreatment process is specifically: washing the glass plate successively with water, ethanol and acetone, and then drying.

7. The method of claim 1, wherein the method is characterized by the steps of: a) preparing a mixture of a thermoluminescent material and a binder; b) coating the mixture on a substrate; c) drying the coated mixture; d) cutting the dried coated mixture into a desired shape; and e) packaging the desired shape in a protective material. In step 5), during the process of coating the gel-like mixture G on the substrate, the height of the doctor blade is 100-1000 μm, and the coating speed is 1-3 m / min; The annealing temperature is 100-200 °C, and the annealing time is 30-90 min.

8. A thermoluminescence film for an accumulated X-ray dosimeter, characterized by, The preparation method is prepared by any one of claims 1-7.

9. The use of a thermoluminescent film for a cumulative X-ray dosimeter according to claim 8 in an intelligent monitoring system, characterized in that, The intelligent monitoring system is used to accumulate X-ray dosimetry.

10. Use according to claim 9, characterized in that, The intelligent monitoring system comprises a photoelectric sensing element, a thermoluminescence film, a hot stage and a terminal device. In use, the thermoluminescence film for storing cumulative dose is placed on the hot stage, and the thermoluminescence film is heated at a rate of 1 K·s -1 -1 to 360 K, and kept at 360 K for 200 s. During this period, the photoelectric sensing element collects the light signal released by the thermoluminescence film, and then the light signal is wirelessly transmitted to the terminal device to display the spectral information and the cumulative dose value.

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