A method for preparing a polyester film surface aluminum film for a nuclear radiation detector window

Abstract

This invention discloses a method for preparing an aluminum film on the surface of a polyester film for use in nuclear radiation detector windows. The method involves magnetron sputtering ion plating on a polyester film substrate to deposit an aluminum-coated ultrathin polyester film. This invention selects a polyester film only a few micrometers thick, as such films possess strong chemical and physical stability, abrasion resistance, chemical resistance, high temperature resistance, and high toughness, making them easy to process and inspect. Aluminum is chosen as the film layer material because it has high reflectivity from the ultraviolet to the infrared region, and aluminum does not easily produce induced radiation, i.e., it does not have secondary radioactivity, thus not affecting subsequent detection and obtaining accurate measurement results. The designed aluminum-coated ultrathin polyester film includes a polyester film and aluminum films deposited on both sides of the polyester film, making it an excellent material for preparing nuclear radiation detector windows.

Description

Technical Field

[0001] This invention belongs to the field of polymer material surface coating technology, specifically relating to a method for preparing an aluminum film on the surface of a polyester film for use in nuclear radiation detector windows. Background Technology

[0002] While nuclear science and technology bring enormous economic benefits, they also pose significant safety risks. Nuclear radiation detection technology is one of the crucial means of effectively utilizing and protecting against nuclear radiation. The aluminized polyester film is the first component through which radiated particles pass into the optical dark chamber of the detector for analysis. It needs to have a certain filtering capability, be resistant to secondary radiation, and allow radiated particles to pass through, in order to block stray light signals, avoid electromagnetic interference, and accurately detect radiation. Although domestically produced nuclear radiation monitoring instruments can be well applied in engineering projects after years of engineering applications and practice, a critical shortcoming remains: the need to import some core components, one of which is the aluminized film window. Preparing an aluminized polyester film that meets the requirements for use and studying its microstructure and properties provides an important theoretical and practical foundation for the realization of domestically produced nuclear radiation detectors.

[0003] Metallized polyester film is produced by depositing an extremely thin layer of aluminum atoms onto the surface of a polyester film substrate in a vacuum environment. Currently, polyester films are available in thicknesses of 2μm, 6μm, 10μm, and 12μm. However, the thickness requirements for polyester films used in nuclear radiation detector windows are stringent, falling within the micrometer range. The material is soft and has very high tensile strength, making aluminum deposition on its surface extremely difficult. First, the metallization temperature is typically 35-45℃. Polyester film, being a large organic molecule, has poor temperature resistance. Regardless of the process used, vacuum metallization inevitably subjectes the substrate material to thermal effects, thus limiting the deposition temperature. Furthermore, the properties of plastics and aluminum differ significantly. For example, plastics have low surface energy and poor surface polarity, making it easy for polyester film surfaces to attract small particles such as dust. Regarding their coefficients of thermal expansion, they differ by an order of magnitude. During or after the formation of the metallized polyester film, the resulting thermal stress can cause the aluminum film layer to crack or even detach. These factors lead to poor adhesion between the polyester and aluminum film layers. In addition, because polyester film is light and thin, wrinkles or scratches, or even deformation and breakage, are easily found on the film surface. Therefore, strict requirements are placed on the sputtering process and the control of the operating speed of the polyester film.

[0004] Due to the aforementioned factors, the preparation of aluminum coatings on the surface of polyester films that meet the requirements presents significant challenges. Domestically produced products cannot meet the requirements for use in nuclear radiation detectors, and currently, imports are the primary source of supply. Considering the risk of supply disruptions and the massive demand for α and β surface contamination monitoring equipment in China, the development of domestically produced aluminum-coated polyester films is imperative.

[0005] Therefore, in view of the existing technical problems and the actual situation, there is a need for a method to prepare a double-sided aluminized polyester film that meets the requirements of nuclear radiation detector windows. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing an aluminum film on the surface of a polyester film for use in nuclear radiation detector windows. This method involves depositing an aluminum-coated ultrathin polyester film onto a polyester film substrate using magnetron sputtering ion plating. The polyester film possesses strong chemical and physical stability, resistance to abrasion and chemicals, high temperature resistance, and high toughness, making it easy to process and subsequently tested. Aluminum is chosen as the film material because it has high reflectivity from the ultraviolet to the infrared region, and aluminum does not easily produce induced radiation (i.e., no secondary radioactivity), thus not affecting subsequent testing and allowing for accurate measurement results. Therefore, the designed aluminum-coated ultrathin polyester film is one of the excellent materials for preparing nuclear radiation detector windows.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing an aluminum film on the surface of a polyester film for a nuclear radiation detector window, characterized in that the method includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to obtain the magnetron sputtering equipment containing the polyester film substrate. Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field of the target material is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a mass purity greater than 99.99%, the target current is 1.5A~3.0A, the negative bias voltage of the substrate is -60V~-200V, the gas pressure in the sputtering equipment is 0.3Pa~1.0Pa, the target-substrate distance is 20cm~50cm, the rotation speed of the turntable is 2r / min~5r / min, and the coating deposition time is 10min~60min. The changes in equipment operating parameters and process parameters are recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained; the aluminum-coated ultrathin polyester film includes a polyester film and an aluminum film coated on both sides of the polyester film.

[0008] This invention involves mounting a metal frame fixture with a polyester film substrate onto a substrate turntable within a magnetron sputtering device. The turntable revolves, causing the polyester film substrate to rotate. The polyester film is then sequentially cleaned and coated, with controlled preparation parameters to ensure aluminum film deposition on both sides of the polyester film without damage. Data is recorded every 5 minutes to track changes in equipment and process parameters during the coating process, allowing for continuous monitoring and ensuring the quality of the aluminum film. This results in an ultrathin aluminum-coated polyester film that is opaque but allows the passage of α, β, and γ radioactive particles, making it suitable for use in nuclear radiation detector windows. The choice of negative bias voltage in the deposition process of this invention affects whether the polyester film substrate is damaged during deposition. By controlling the negative bias voltage to -60V to -120V, a complete and undamaged aluminum film can be prepared. The gas pressure in the sputtering equipment affects the density of the aluminum film, and the time affects the thickness of the aluminum film. By controlling the gas pressure to 1.0Pa to 3.0Pa and the deposition time to 5min to 20min, a dense aluminum film with the required thickness can be prepared. The rotation speed of the turntable affects the uniformity of the prepared aluminum film. A rotation speed of 2r / min to 5r / min can prepare a uniform aluminum film. The aluminum film deposited on both sides of the polyester film in this invention has a high reflectivity from the ultraviolet to the infrared region, which can effectively block stray light signals such as visible light and ultraviolet light. In addition, aluminum easily forms a thin aluminum oxide film, which protects the aluminum film. Furthermore, aluminum is relatively light and will not easily generate induced radiation, so it will not affect subsequent detection.

[0009] The above-mentioned method for preparing an aluminum film on the surface of a polyester film for a nuclear radiation detector window is characterized in that, in step one, the vacuuming is performed by evacuating the sputtering equipment to a vacuum level of 7 × 10⁻⁶. -3 Pa ~ 6×10 -4 Pa. This invention prevents impurities from affecting the film deposition by controlling the vacuum level.

[0010] The above-described method for preparing an aluminum film on the surface of a polyester film for a nuclear radiation detector window is characterized in that, in step two, the negative bias voltage of the glow discharge cleaning is -60V to -120V, the gas pressure in the sputtering equipment is 1.0Pa to 3.0Pa, the time is 5min to 20min, and the rotation speed of the rotary table is 2r / min to 5r / min. This invention ensures the cleaning effect by controlling the parameters of the glow discharge cleaning, thereby guaranteeing the quality and flatness of the subsequently prepared aluminum film.

[0011] The above-described method for preparing an aluminum film on the surface of a polyester film for a nuclear radiation detector window is characterized in that, in step three, the sputtering equipment containing the clean polyester film substrate with an electromagnetic field is filled with an inert gas, wherein the inert gas is argon or helium with a mass purity greater than 99.999%. This invention provides an inert atmosphere through the use of an inert gas, preventing the metal material from oxidizing or reacting with other gases during the coating process. Furthermore, it can adjust the composition and structure of the film, making the film composition more uniform and improving the film quality and performance.

[0012] The above-described method for preparing an aluminum film on the surface of a polyester film for a nuclear radiation detector window is characterized in that the thickness of the polyester film in step five is 1 μm to 3 μm, and the thickness of the aluminum film is 50 nm to 500 nm. This invention, by controlling the thickness of the polyester film, ensures a smooth and clean surface, good thermal stability, strong chemical and physical stability, and resistance to photoaging. It also effectively blocks some ultraviolet light. The aluminum film with a thickness of 50 nm to 500 nm is a nanofilm, possessing high aluminum reflectivity and high α and β particle transmittance.

[0013] Compared with the prior art, the present invention has the following advantages: 1. The polyester film selected in this invention has advantages such as strong chemical and physical stability, abrasion resistance, chemical resistance, high temperature resistance and high toughness. It is easy to process and conduct subsequent testing. Aluminum is selected as the film material because it has high reflectivity from the ultraviolet light region to the infrared light region, and aluminum does not easily produce induced radiation, that is, it will not have secondary radioactivity, thus it will not affect subsequent testing and can obtain accurate measurement results. Therefore, the designed aluminum-coated ultrathin polyester film is one of the excellent materials for preparing the window of the nuclear radiation detector.

[0014] 2. This invention employs magnetron sputtering ion plating, which has the advantage of low-temperature deposition and can effectively avoid the problems of substrate deformation and melting caused by the low melting point of polyester film and the high deposition temperature of aluminum film. In addition, this process has a high deposition rate, good reproducibility and is environmentally friendly, making it the best choice for preparing aluminum film on the surface of polyester film.

[0015] 3. In this invention, the thin film is adhered to a lightweight metal frame fixture to form a window shape and fixed on a substrate turntable. During sputtering cleaning and preparation of the working layer, the frame rotates at a constant speed, ensuring thorough cleaning and uniform preparation of the film layer.

[0016] 4. This invention provides an opaque, non-transparent aluminum-coated polyester film for use as a window in a nuclear radiation detector, which allows radioactive particles such as α, β, and γ to pass through, and a method for preparing the same.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a microstructure image of the aluminum-coated ultrathin polyester film prepared in Example 1 of the present invention.

[0019] Figure 2 This is a morphological image of the cross-section of the aluminum-coated ultrathin polyester film prepared in Example 1 of the present invention.

[0020] Figure 3 The image shows the AFM three-dimensional morphology of the aluminum-coated ultrathin polyester film prepared in Example 1 of this invention.

[0021] Figure 4 The XRD patterns are of the aluminum-coated ultrathin polyester films prepared in Examples 1 to 4 of this invention.

[0022] Figure 5 The transmittance curves of the aluminum-coated ultrathin polyester film and the polyester film substrate prepared in Examples 1 to 4 of this invention are shown in the ultraviolet and visible light regions. Detailed Implementation

[0023] Example 1 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 7×10⁻⁶. -3 Pa, thus obtaining a magnetron sputtering device containing a polyester film substrate; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -80V, the gas pressure inside the sputtering equipment is 1.5Pa, the time is 5min, and the speed of the turntable revolving is 3r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a purity greater than 99.99%, the target current is 1.7A, the negative bias voltage of the substrate is -80V, the gas pressure inside the sputtering equipment is 0.6Pa, the target-substrate distance is 30cm, the rotary table rotation speed is 2r / min, and the coating deposition time is 20min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0024] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 50 nm to 110 nm.

[0025] Figure 1 The image shows the microstructure of the aluminum-coated ultrathin polyester film prepared in this embodiment. Figure 1 As can be seen from the figure, the aluminum film prepared in this embodiment has a dense and flat surface, without defects such as large particle accumulation and pores, and the film quality is good. The Al particles in the film are small in size and uniformly distributed, which lays the foundation for good light blocking properties.

[0026] Figure 2 Here is a morphology image of the cross-section of the aluminized ultrathin polyester film prepared in this embodiment. Figure 2 As can be seen, the aluminum film prepared in this embodiment is intact, without any peeling, and has a thickness of 107.2 nm, which is very thin, thus eliminating the possibility of pinholes to a certain extent.

[0027] Figure 3 The image shows the AFM three-dimensional morphology of the aluminized ultrathin polyester film prepared in this embodiment. Figure 3 As can be seen from the above, the Al particles on the surface of the aluminum film prepared in this embodiment grow in a columnar manner along the Z-axis, the film layer is very dense, the height of the aluminum particles is very small, with a maximum of 9.8 nm and a minimum of -8.0 nm, and the aluminum film layer has high flatness.

[0028] Example 2 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 5×10⁻⁶. -3 A magnetron sputtering device containing a polyester film substrate was obtained; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -100V, the gas pressure inside the sputtering equipment is 1.0Pa, the time is 5min, and the speed of the turntable revolving is 3r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a purity greater than 99.99%, the target current is 2.0A, the negative bias voltage of the substrate is -100V, the gas pressure inside the sputtering equipment is 0.6Pa, the target-substrate distance is 40cm, the rotation speed of the rotary table is 2r / min, and the coating deposition time is 30min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0029] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 50 nm to 80 nm.

[0030] Example 3 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 6×10⁻⁶. -4 Pa, thus obtaining a magnetron sputtering device containing a polyester film substrate; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -60V, the gas pressure inside the sputtering equipment is 1.5Pa, the time is 10min, and the speed of the turntable revolving is 2r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. The target material for the coating deposition is an aluminum target with a purity greater than 99.99%, the target current is 2.3A, the negative bias voltage of the substrate is -80V, the gas pressure inside the sputtering equipment is 0.6Pa, the target-substrate distance is 20cm, the rotation speed of the rotary table is 2r / min, and the coating deposition time is 20min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0031] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 50 nm to 100 nm.

[0032] Example 4 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 6×10⁻⁶. -4 Pa, thus obtaining a magnetron sputtering device containing a polyester film substrate; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -120V, the gas pressure inside the sputtering equipment is 3.0Pa, the time is 5min, and the speed of the turntable revolving is 5r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a purity greater than 99.99%, the target current is 2.6A, the negative bias voltage of the substrate is -60V, the gas pressure in the sputtering equipment is 0.5Pa, the target-substrate distance is 50cm, the rotary table rotation speed is 3r / min, and the coating deposition time is 20min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0033] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 80 nm to 120 nm.

[0034] Figure 4 The XRD patterns of the aluminized ultrathin polyester films prepared in Examples 1 to 4 of this invention are shown below. Figure 4 As can be seen, four characteristic peaks appear in the range of 35°~90°, with peak positions at 2θ=38.4°, 44.7°, 65.1° and 78.2° respectively, and their diffraction indices are (111), (200), (220) and (311) respectively. This indicates that the aluminum nanoparticle coating deposited on the polyester film substrate by magnetron sputtering has a polycrystalline face-centered cubic structure, among which the Al(111) characteristic peak is the strongest peak. This shows that the aluminum nanoparticle coating prepared by DC magnetron sputtering technology can effectively control its preferential growth along the (111) crystal plane.

[0035] Figure 5 The transmittance curves of the aluminized ultrathin polyester film and the polyester film substrate prepared in Examples 1 to 4 of this invention are shown in the ultraviolet and visible light regions. Figure 5 As can be seen, the transmittance of the polyester film substrate is extremely low, almost zero, before 300nm. This is because the polymer film has a strong absorption effect on ultraviolet light. The transmittance between 300nm and 800nm ​​is about 80%. The transmittance of the aluminized polyester film is significantly lower than that of the substrate film. This is because Al has a very high reflectance coefficient. Therefore, the transmittance of the aluminized polyester film drops sharply. The transmittance is slightly higher at a current of 1.7A, about 10%, while the transmittance at other parameters is very low, almost zero.

[0036] Example 5 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 5×10⁻⁶. -3 Pa, thus obtaining a magnetron sputtering device containing a polyester film substrate; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -100V, the gas pressure inside the sputtering equipment is 2.0Pa, the time is 15min, and the speed of the turntable revolving is 4r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a purity greater than 99.99%, the target current is 1.5A, the negative bias voltage of the substrate is -80V, the gas pressure in the sputtering equipment is 1.0Pa, the target-substrate distance is 25cm, the rotation speed of the rotary table is 2r / min, and the coating deposition time is 60min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0037] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 50 nm to 100 nm.

[0038] Example 6 This embodiment includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to a vacuum level of 6×10⁻⁶. -4 Pa, thus obtaining a magnetron sputtering device containing a polyester film substrate; Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. The negative bias voltage of the glow discharge cleaning is -90V, the gas pressure inside the sputtering equipment is 2.5Pa, the time is 10min, and the speed of the turntable revolving is 4r / min. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material, and fill the sputtering equipment with argon gas with a mass purity greater than 99.999% to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a purity greater than 99.99%, the target current is 1.5A, the negative bias voltage of the substrate is -80V, the gas pressure in the sputtering equipment is 1.0Pa, the target-substrate distance is 40cm, the rotary table rotation speed is 2r / min, and the coating deposition time is 40min. Data is recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained.

[0039] Testing revealed that this embodiment produced an opaque, non-transparent, double-sided aluminum-coated ultrathin polyester film that allows α and β ray particles to pass through. The polyester film has a thickness of 2 μm, and the aluminum film has a thickness of 50 nm to 80 nm.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for producing a polyester film surface aluminum film for a nuclear radiation detector window, characterized by, The method includes the following steps: Step 1: Install the metal frame fixture with the polyester film substrate attached onto the substrate turntable inside the magnetron sputtering equipment, and then evacuate the sputtering equipment to obtain the magnetron sputtering equipment containing the polyester film substrate. Step 2: Open the turntable of the magnetron sputtering equipment containing the polyester film substrate obtained in Step 1, so that the turntable revolves and drives the polyester film substrate to rotate. Then, perform glow discharge cleaning on the polyester film substrate using argon ions to obtain a clean polyester film substrate. Step 3: Establish a horizontal orthogonal electromagnetic field between the clean polyester film substrate obtained in Step 2 and the target material to obtain a clean polyester film substrate with an electromagnetic field; the electromagnetic field of the target material is powered by a DC power supply, and the voltage of the pulse bias power supply is -50V to -1000V. Step 4: The clean polyester film substrate with an electromagnetic field obtained in Step 3 is coated and deposited using magnetron sputtering ion plating technology to obtain a sample. In the coating deposition, the target material is an aluminum target with a mass purity greater than 99.99%, the target current is 1.5A~3.0A, the negative bias voltage of the substrate is -60V~-200V, the gas pressure in the sputtering equipment is 0.3Pa~1.0Pa, the target-substrate distance is 20cm~50cm, the rotation speed of the turntable is 2r / min~5r / min, and the coating deposition time is 10min~60min. The changes in equipment operating parameters and process parameters are recorded every 5 minutes. Step 5: After the sample obtained in Step 4 is kept in the furnace and then cooled to room temperature, an aluminum-coated ultrathin polyester film is obtained; the aluminum-coated ultrathin polyester film includes a polyester film and an aluminum film coated on both sides of the polyester film.

2. The method for manufacturing a polyester film surface aluminum film for a nuclear radiation detector window according to claim 1, characterized by, The vacuuming in step one is to vacuum the sputtering apparatus to 7 x 10 -3 Pa~6 x 10 -4 Pa.

3. The method of claim 1, wherein the polyester film is a Mylar film.

3. The method of claim 1, wherein the polyester film is a Mylar film. In step two, the negative bias voltage for glow discharge cleaning is -60V to -120V, the gas pressure inside the sputtering equipment is 1.0Pa to 3.0Pa, the time is 5min to 20min, and the rotation speed of the turntable is 2r / min to 5r / min.

4. The method of claim 1, wherein the polyester film is a Mylar® film. In step three, the sputtering equipment containing the clean polyester film substrate with the electromagnetic field is filled with an inert gas, which is argon or helium with a mass purity greater than 99.999%.

5. The method of claim 1, wherein the polyester film is a Mylar® film. The thickness of the polyester film in step five is 1μm to 3μm, and the thickness of the aluminum film is 50nm to 500nm.

Images