Application of a free-standing graphene film as a carbon stripper film for heavy ion accelerator

Abstract

The application relates to an application of an independent self-supporting graphene film as a carbon stripping film of a heavy ion accelerator. The ID / IG of the graphene film is less than 0.01, and the AB structure content is more than 90%. The structure makes the carbon film have high electric conductivity, high heat conductivity, good mechanical properties and flexibility. High electron content and long carrier total duration make particles more easily capture electrons from film atoms, change the charge state of the particles, and the generated heat is easily conducted by the carbon film, prevents the center from overheating and makes the carbon film curl and tear, and is damaged. Good mechanical properties ensure that the carbon film is not easily damaged in the use process, the flatness and appearance are not easily damaged, and a long service life is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heavy ion accelerator carbon stripping film, in particular to the application of independent self-supporting graphene film as heavy ion accelerator carbon stripping film. BACKGROUND

[0002] Ion accelerator is a device for artificially producing fast heavy ion beam (ion with mass greater than alpha particle). It uses certain form of electromagnetic field to accelerate heavy ions, which can provide high-energy heavy ion beam with speed up to several thousand, several ten thousand or even close to 300,000 km / s, to bombard atomic nucleus, atom, molecule, solid lattice or even biological cell. It has important and wide application in industrial and agricultural production, medical and health care, science and technology and other fields.

[0003] Stripping film is an important part of the heavy ion acceleration process. Since the melting point of carbon is the highest among elemental materials and it has good chemical stability, the accelerator generally uses carbon film as the stripping body of the outer charge of heavy ion nucleus to obtain higher charge state. The service life of the stripping film will directly affect the service life of the accelerator. The conventional carbon stripping film is prepared by alternating current and direct current carbon arc discharge method. The carbon stripping film obtained by this method is amorphous carbon, which has poor mechanical properties and cannot accurately control uniformity, and often has a short service life. At the same time, due to the stress of the carbon stripping film prepared in the preparation process, it cannot be self-supported without external force, and has to be attached to the film by using a target frame or a glass sheet substrate. The introduction of the target frame or the release agent reduces the quality of the beam flow, such as the size of the beam flow, and affects the operating efficiency of the accelerator. In addition, the expensive preparation equipment and high-quality carbon source also increase the production difficulty of the preparation process.

[0004] The service life of the carbon stripping film is mainly determined by its mechanical properties and the performance of the ion beam. Since diamond-like carbon film (DLC) has good mechanical properties, diamond-like stripping film is now commonly used to replace ordinary carbon film, which has made certain progress in service life enhancement. Commonly used methods include plasma enhanced chemical vapor deposition (PECVD), magnetic filter cathode vacuum arc deposition (FCVA), direct current glow sputtering method, laser plasma ablation method, etc. However, diamond-like carbon film (DLC) needs to be attached to a substrate. A large number of studies have found that there is a lot of residual stress in the diamond-like carbon film (DLC), which not only weakens the bonding strength between the film and the substrate, but also causes the film to peel off and fail prematurely during service, so the service life is still not ideal. SUMMARY

[0005] The present application aims at the shortcomings of the prior art and provides an application of independent self-supporting graphene film as heavy ion accelerator carbon stripping film.

[0006] The technical scheme of the present application is: application of an independent self-supporting graphene film as a carbon stripping film of a heavy ion accelerator, wherein the ID / IG of the graphene film is less than 0.01, and the AB structure content is more than 90%; the graphene film has a complete graphite structure, and the total carrier duration is greater than 15 ps, so that the graphene film has high conductivity, high thermal conductivity, high mechanical properties and flexibility (elongation at break is greater than 4%); the high electron content and long total carrier duration make it easier for the beam particles to capture electrons from the film atoms, so that the charge state of the particles changes, and the heat generated is easily conducted away by the high thermal conductivity graphene film, preventing the graphene film from being overheated and curled and torn, and thus being damaged; the good mechanical properties ensure that the graphene film is not easily damaged in the process of use, and the independent self-supporting structure does not need a substrate, so that the graphene film is clamped by a clamp and placed on a carrier during use, and the graphene film is installed by being aligned and closed, thereby avoiding damage to the beam by the target frame or release agent, and ensuring the high efficiency of the heavy ion accelerator.

[0007] The preparation method of the independent self-supporting graphene film comprises a method a for preparing an independent self-supporting graphene film with a thickness of less than or equal to 50 nm and a method b for preparing an independent self-supporting graphene film with a thickness of greater than 50 nm.

[0008] a. Preparation of an independent self-supporting graphene film with a thickness of less than or equal to 50 nm

[0009] (a1) preparing an oxidized graphene aqueous solution with a concentration of 0.5-10 ug / mL, and performing filtration on the oxidized graphene aqueous solution to form a film on an aluminum oxide (AAO) substrate;

[0010] (a2) placing the oxidized graphene film on the AAO film in a four-fluorine tank, and performing high-temperature fumigation on the oxidized graphene film with hydriodic acid at 85 DEG C for 12 h;

[0011] (a3) heating and sublimating camphor to uniformly adsorb on the surface of the reduced graphene oxide film, and then cooling at room temperature, so that the reduced graphene oxide film automatically separates from the AAO film;

[0012] (a4) volatilizing the camphor from the reduced graphene oxide film to obtain an independent self-supporting reduced graphene oxide film; and sintering the reduced graphene oxide film at high temperature to repair defects, so as to obtain an independent self-supporting graphene film with a thickness of less than or equal to 50 nm.

[0013] b. Preparation of an independent self-supporting graphene film with a thickness of greater than 50 nm

[0014] (b1) uniformly dispersing oxidized graphene and graphitizable polymers in an easy-to-dissolve solvent to form a mixture, and uniformly coating the mixture on a substrate to form a composite film;

[0015] (b2) insert the substrate into deionized water at an angle, the composite film is quickly phase separated and formed to be peeled off from the substrate; dry the film floating on the surface of the solution with an infrared lamp.

[0016] (b3) transfer the composite film to a volatile solvent with a porous substrate;

[0017] (b4) after infiltration, transfer the film and the substrate out, and after drying, the film is automatically separated and collected to obtain an independent self-supporting graphene oxide nanofilm;

[0018] (b5) high-temperature sintering of the graphene oxide nanofilm obtained in step (b4) to obtain an independent self-supporting graphene film with a thickness greater than 50 nm.

[0019] Further, the size of the graphene oxide sheet is 30-100 um.

[0020] Further, the temperature of the high-temperature sintering is greater than or equal to 2800°C.

[0021] Further, the porosity of the AAO film in step (a1) is not less than 50%.

[0022] Further, the graphitizable polymer in step (b1) is polyacrylonitrile (PAN), polyimide (PI), mesophase pitch, etc. The mass ratio of the graphene oxide is 7:3-5:5.

[0023] Further, the solvent in step (b1) is dimethylformamide (DMF), dimethylacetamide (DMAC), or N-methyl pyrrolidone (NMP).

[0024] Further, the solid content of the mixture in step (b1) is 1-1.5%.

[0025] Further, the substrate in step (b1) is a flat substrate of common materials such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), silicon dioxide (SiO2), silicon wafer, aluminum oxide, etc.

[0026] Further, the coating method in step (b1) is using a Mayer rod to scrape.

[0027] Further, the solvent content of the composite film in step (b2) is more than 97%.

[0028] Further, the insertion angle in step (b2) is between 0-45° (not including the endpoints).

[0029] Further, the porous substrate in step (b3) is a filter screen with a mesh size less than 500.

[0030] Further, the step (b3) uses ethanol, isopropyl alcohol, ethyl acetate and other solvents with small surface tension.

[0031] In the above preparation method, the wet assembly method is used instead of the traditional AC carbon arc discharge method for preparation, which is more cost-effective (reflected in the need for expensive sputtering equipment and raw materials), and can obtain multiple carbon stripping films with different thicknesses in a short time, and the time cost is less. The preparation method b uses graphitizable polymers, which is more cost-effective than graphene oxide, and the use of graphene oxide to induce the formation of graphite structure in high polymer at high temperature greatly reduces the cost of raw materials. The Mayer rod coating ensures uniform coating of the liquid, solving the problem of uneven thickness in the traditional method. The perfect graphite structure and highly ordered AB stacking formed after high-temperature sintering ensure long carrier total duration and abundant electronic content, which can be applied to the field of heavy ion accelerators. Excellent mechanical properties and thermal conductivity make the carbon stripping film less likely to be damaged by the beam in the application process, and have a longer service life.

[0032] The application has the advantages that: the application uses an independent self-supporting graphene film as a carbon stripping film for a heavy ion accelerator, effectively promotes the change of particle charge state, and the excellent thermal conductivity and mechanical properties and the self-supporting characteristics effectively ensure the service life. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Figure 8 is a Raman test graph of a 25nm graphite-based carbon stripping film;

[0034] Figure 2 Figure 9 is a carrier total duration graph of graphite-based carbon stripping films with different thicknesses a) 25nm ultra-thin film of a pure graphene oxide system; b) 30nm ultra-thin film of a pure graphene oxide system; c) 50nm ultra-thin film of a pure graphene oxide system; d) 50nm ultra-thin film of a graphene oxide composite system; e) 100nm ultra-thin film of a graphene oxide composite system; f) 150nm ultra-thin film of a graphene oxide composite system;

[0035] Figure 3 Figure 10 is a stress-strain graph of graphite-based carbon stripping films a) 25nm ultra-thin film of a pure graphene oxide system; b) 30nm ultra-thin film of a pure graphene oxide system; c) 50nm ultra-thin film of a pure graphene oxide system; d) 50nm ultra-thin film of a graphene oxide composite system; e) 100nm ultra-thin film of a graphene oxide composite system; f) 150nm ultra-thin film of a graphene oxide composite system;

[0036] Figure 4 Figure 11 is a cross-sectional TEM graph of a 50nm graphite-based carbon stripping film;

[0037] Figure 5Raman test graph of the graphite-based carbon stripping film 50, 100, 150 nm prepared for the graphene oxide composite system. DETAILED DESCRIPTION

[0038] To further illustrate the technical means and effects adopted by the present application to achieve the predetermined inventive objectives, the specific embodiments, structures, features and effects according to the present application are described in detail below in conjunction with the drawings and preferred embodiments.

[0039] The application discloses an application of an independent self-supporting graphene film as a carbon stripping film of a heavy ion accelerator, and utilizes a wet assembly method to obtain a carbon stripping film with a complete graphite structure, more than 90% AB ordered stacking, and a long carrier total duration (more than 15 ps). The structure enables the carbon film to have high electric conductivity, high heat conductivity, good mechanical properties and flexibility. Meanwhile, the independent self-supporting structure avoids damage of a target frame or a release agent to a beam, and guarantees high efficiency application of the heavy ion accelerator.

[0040] The application is further described below in conjunction with examples:

[0041] Example 1: pure graphene oxide system

[0042] (1) graphene oxide is dispersed in deionized water at 0.5 ug / ml, and an AAO film with a porosity of 60% is used as a substrate to draw about 50 nm of graphene oxide ultra-thin film.

[0043] (2) the graphene oxide film on the AAO film is placed in a four-fluorine tank, and is high-temperature smoked with hydriodic acid at 85 DEG C for 12 hours;

[0044] (3) camphor is heated to sublimate and uniformly adsorbed on the surface of the reduced graphene oxide film, and then is cooled at room temperature, so that the reduced graphene oxide film is automatically separated from the AAO film;

[0045] (4) the reduced graphene oxide film obtained above is volatilized to remove camphor, and an independent self-supporting reduced graphene film is obtained. ℃ high-temperature sintering, and repairing defects, so that a graphite-based carbon stripping film with a thickness of about 25 nm is finally obtained.

[0046] The film has low defect content, perfect graphite structure, and uniform structure thickness, such as Figure 1 Raman data show that ID / IG is less than 0.01 (almost invisible D peak), AB content is 96%, and carrier total duration is 26 ps (such as Figure 2 a). Meanwhile, the mechanical properties are good, and the elongation at break is 9.5% (such as Figure 3 a). The film edge is clamped by a clamp, the film is placed on a carrier, and after alignment and closing of the carrier are completed, the beam current through the stripping film has no obvious change, so that the film can be installed and used. The beam current is 107 Ag- The ion beam (160 nA, beam spot is Ф8 mm) was tested for film service life. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the 50% decrease of the ion beam intensity after the carbon film was stripped was recorded. It was found that the service life was 170 min, and the service life was long. At the same time, the equipment is simple and the cost is lower.

[0047] Example 2: Pure graphene oxide system

[0048] (1) Disperse graphene oxide in deionized water at 5 ug / ml, and use a 50% porosity AAO film as a substrate to extract a graphene oxide ultra-thin film of about 60 nm.

[0049] (2) Put the graphene oxide film on the AAO film into a four-fluorine tank, and high-temperature fumigate with hydriodic acid at 85°C for 12 h;

[0050] (3) Heat camphor to sublimate and uniformly adsorb on the surface of the reduced graphene oxide film. Then cool at room temperature, and the reduced graphene oxide film will automatically separate from the AAO film;

[0051] (4) Volatilize the camphor from the obtained reduced graphene oxide film to obtain an independent self-supporting reduced graphene film. The reduced graphene film 2800 ℃ High-temperature sintering, defect repair, and finally obtain a graphene-based carbon stripping film of about 30 nm.

[0052] The film has low defect content, perfect graphite structure, uniform structure thickness, ID / IG less than 0.01 (almost invisible D peak), AB content of 95.3%, and total carrier duration of 25.5 ps (as shown in Figure 2 b). At the same time, the mechanical properties are good, and the elongation at break is 9.5% (as shown in Figure 3 b). The edge of the film is clamped by a clamp, and the film is placed on the carrier. After the installation is completed, the beam current through the stripping film has no obvious change, and the film can be installed and used. The beam current is 107 Ag - The ion beam (160 nA, beam spot is Ф8 mm) was tested for film service life. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the 50% decrease of the ion beam intensity after the carbon film was stripped was recorded. It was found that the service life was 170 min, and the service life was long. At the same time, the equipment is simple and the cost is lower.

[0053] Example 3: Pure graphene oxide system

[0054] (1) Disperse graphene oxide in deionized water at 10 ug / ml, and use a 55% porosity AAO film as a substrate to extract a graphene oxide ultra-thin film of about 100 nm.

[0055] (2) Place the graphene oxide film on the AAO membrane in a tetrafluoroethylene tank and fumigate with hydroiodic acid at 85°C for 12 hours.

[0056] (3) The camphor is heated and sublimated, and uniformly adsorbed on the surface of the reduced graphene oxide film. After cooling at room temperature, the reduced graphene oxide film will automatically detach from the AAO film.

[0057] (4) The camphor was evaporated from the reduced graphene oxide film obtained above to obtain an independent, self-supporting reduced graphene film. The reduced graphene film was then subjected to a 2800-degree rotation. ℃ High-temperature sintering repairs defects, ultimately yielding a graphite-based carbon exfoliation film of approximately 50 nm.

[0058] The film has a low defect content, a well-developed graphite structure, and uniform thickness (e.g., Figure 4 The ID / IG ratio is less than 0.01 (the D peak is almost invisible), the AB content is 94.7%, and the total carrier duration is 25 ps (e.g., Figure 2 c). It also possesses good mechanical properties, with an elongation at break of 9.4% (e.g., ...). Figure 3 c). Clamp the membrane edge with the fixture, place the membrane on the carrier, align and close the carrier. After installation, if the beam intensity does not change significantly after passing through the stripping membrane, it is ready for use. Use 107Ag. - The membrane lifetime was tested using an ion beam (160 nA, beam spot size Ф8 mm). With a constant incident current, the time it took for the ion beam current to decrease by 50% after carbon film stripping was recorded, revealing a lifetime of 160 minutes, which is long. Furthermore, the equipment is simple and has a lower cost.

[0059] Example 4: Graphene Oxide Composite System

[0060] (1) Graphene oxide and polyacrylonitrile are uniformly dispersed in DMF, wherein the mass ratio of graphene oxide to polyacrylonitrile is 5:5; the solid content of the mixture is 1%.

[0061] (2) A 12µm film was coated onto a PP substrate using a Mayer rod by coating a mixture of graphene oxide and polyacrylonitrile. When the solvent content of the film was 99%, the substrate was inserted into water at a 44° angle.

[0062] (3) The composite membrane is transferred to ethanol using a filter screen. After wetting, the membrane and substrate are transferred out. After drying, the membrane is automatically detached and collected to obtain an independently supported composite membrane.

[0063] (4) Take the ultrathin film 2800 obtained in step (3) ℃ High-temperature sintering ultimately yields a graphite-based carbon film of approximately 50 nm.

[0064] The film has a low defect content and a well-developed graphite structure. For example...Figure 5 As shown, ID / IG is less than 0.01 (D peak is almost invisible), AB content is 94%, and total carrier duration is 25 ps (as shown). Figure 2 d). It also possesses good mechanical properties, with an elongation at break of 9.4% (e.g., Figure 3 d). The clamp holds the membrane edge, places the membrane on the carrier, aligns it, and closes the carrier. After installation, the beam current does not change significantly after passing through the stripping membrane, indicating it is ready for use. (Use 107Ag) - The membrane lifetime was tested using an ion beam (160 nA, beam spot size Ф8 mm). With a constant incident current, the time it took for the ion beam current to decrease by 50% after carbon film stripping was recorded, revealing a lifetime of 134 minutes, which is long. Furthermore, the equipment is simple, the polymer raw materials are inexpensive, and the overall cost is lower.

[0065] Example 5: Graphene Oxide Composite System

[0066] (1) Graphene oxide and polyimide (PI) are uniformly dispersed in NMP, wherein the mass ratio of graphene oxide to polyimide is 3:7; the solid content of the mixture is 1.2%.

[0067] (2) A 20µm film was coated onto a PE substrate using a Mayer rod to apply a mixture of graphene oxide and asphalt. When the solvent content of the film was 98%, the substrate was inserted into water at a 25° angle.

[0068] (3) The composite membrane is transferred to isopropanol using a filter screen. After wetting, the membrane and substrate are transferred out. After drying, the membrane is automatically detached and collected to obtain an independently supported composite membrane.

[0069] (4) Take the ultrathin film 2800 obtained in step (3) ℃ High-temperature sintering ultimately yields a graphite-based carbon film of approximately 100 nm.

[0070] The film has a low defect content and a well-developed graphite structure. For example... Figure 5 As shown, ID / IG is less than 0.01 (D peak is almost invisible), AB content is 93%, and total carrier duration is 23 ps (as shown). Figure 2 e). It also possesses good mechanical properties, with an elongation at break of 6.7% (e.g., Figure 3 e). Clamp the membrane edge with the fixture, place the membrane on the carrier, align and close the carrier. After installation, if the beam intensity does not change significantly after passing through the stripping membrane, it is ready for use. Use 107Ag. -The ion beam (160 nA, beam spot is Ф8 mm) was used to test the service life of the film. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the decrease of the ion beam flow intensity by 50% after the carbon film was stripped was recorded. It was found that the service life was 130 min, and the service life was long. At the same time, the equipment is simple, the polymer raw material is low, and the cost is lower.

[0071] Example 6: Graphene oxide composite system

[0072] (1) The graphene oxide and mesophase pitch were uniformly dispersed in DMAC, and the mass ratio of graphene oxide to mesophase pitch was 4:6; the solid content of the mixed solution was 1.5%.

[0073] (2) The graphene oxide and pitch mixture was coated on a polyethylene terephthalate (PET) substrate by a Mayer rod coating method to form a 25 um film. When the mass content of the solvent in the film was 98%, the substrate was inserted into water at an angle of 2°.

[0074] (3) The composite film was transferred to ethyl acetate by a filter screen, and after soaking, the film and the substrate were transferred out, and after drying, the thin film was automatically separated and collected to obtain an independently supported composite film.

[0075] (4) The ultrathin film obtained in step (3) was placed on a glass substrate and dried to form a graphene oxide film. ℃ High temperature sintering, finally obtained about 150 nm graphite-based carbon film.

[0076] The film has low defect content and perfect graphite structure. As shown in Figure 5 , the ID / IG is less than 0.01 (almost no D peak), the AB content is 92%, and the total carrier duration is 21.5 ps (as shown in Figure 2 f). At the same time, the mechanical properties are good, and the elongation at break is 4.5% (as shown in Figure 3 f). The film was placed on the carrier by clamping the edge of the film with the clamp, and after alignment and closing of the carrier, the beam current did not change significantly after the stripping film, and the installation could be used. The ion beam current was 107 Ag - The ion beam (160 nA, beam spot is Ф8 mm) was used to test the service life of the film. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the decrease of the ion beam flow intensity by 50% after the carbon film was stripped was recorded. It was found that the service life was 130 min, and the service life was long. At the same time, the equipment is simple, the polymer raw material is low, and the cost is lower.

[0077] Comparative Example 1: Film system that cannot be self-supported, pure graphene oxide system

[0078] (1) The graphene oxide was dispersed in deionized water at 5 ug / ml, and an AAO membrane with a porosity of 20% was used as a substrate to extract 50 nm graphene oxide ultrathin film;

[0079] (2) Put the graphene oxide film on the AAO membrane into a fluorotetra tank, and fumigate with hydriodic acid at 85°C for 12 h;

[0080] (3) Heat camphor to sublimate and uniformly adsorb on the surface of the reduced graphene oxide film. Then cool at room temperature. The reduced graphene oxide film cannot automatically separate from the AAO membrane.

[0081] Comparative Example 2: Film system that cannot be self-supported, graphene oxide composite system

[0082] (1) Uniformly disperse graphene oxide and polyacrylonitrile in DMF, wherein the mass ratio of graphene oxide to polyacrylonitrile is 3:7; the solid content of the mixed solution is 1%.

[0083] (2) Apply the graphene oxide and polyacrylonitrile mixed solution to a PP substrate by Mayer rod coating to obtain a 10 μm film. When the mass content of the solvent in the film is 90%, the substrate cannot be inserted into water at an angle of 30° to peel off the film.

[0084] Comparative Example 3: Film system that cannot be self-supported, graphene oxide composite system

[0085] (1) Uniformly disperse graphene oxide and polyacrylonitrile in DMF, wherein the mass ratio of graphene oxide to polyacrylonitrile is 8:2; the solid content of the mixed solution is 3%.

[0086] (2) Apply the graphene oxide and polyacrylonitrile mixed solution to a PET substrate by Mayer rod coating to obtain a 10 μm film. When the mass content of the solvent in the film is 98%, the substrate cannot be inserted into water at an angle of 30° to peel off the film.

[0087] Comparative Example 4: System that cannot be graphitized

[0088] (1) Uniformly disperse graphene oxide and polyether sulfone in DMF, wherein the mass ratio of graphene oxide to polyether sulfone is 5:5; the solid content of the mixed solution is 1%.

[0089] (2) Apply the graphene oxide and polyether sulfone mixed solution to a PP substrate by Mayer rod coating to obtain a 20 μm film. When the mass content of the solvent in the film is 98%, the substrate cannot be inserted into water at an angle of 30°.

[0090] (3) Transfer the composite film to ethanol by using a filter screen. After soaking, the film and the substrate are transferred out, dried, and the thin film is automatically separated and collected to obtain an independently supported composite film.

[0091] (4) The ultra-thin film obtained in step (3) is subjected to 2800 ℃ High-temperature sintering, and an intact carbon film cannot be obtained.

[0092] Comparative Example 5: Pure graphene oxide system, application comparative example

[0093] (1) Disperse graphene oxide in deionized water at 5 ug / ml, and use a 50% porosity AAO film as a substrate to draw-filter a graphene oxide ultra-thin film of about 50 nm.

[0094] (2) Place the graphene oxide film on the AAO film in a fluorotetra tank, and high-temperature fumigate with hydriodic acid at 85°C for 12 h;

[0095] (3) Heat camphor to sublimate and uniformly adsorb on the surface of the reduced graphene oxide film, and then cool at room temperature; the reduced graphene oxide film will automatically detach from the AAO film;

[0096] (4) Volatilize the camphor from the reduced graphene oxide film obtained above to obtain a self-supporting reduced graphene film. The reduced graphene film is 1200 ℃ high-temperature sintered, and finally a graphene-based carbon stripping film of about 30 nm is obtained.

[0097] The film contains a high number of defects and the graphite structure is imperfect, with ID / IG greater than 0.01, AB content of 12%, and total carrier duration of 8 ps. The mechanical properties are poor, with elongation at break of 0.8%. Bonding to the fixed instrument causes a hole.

[0098] Comparative Example 6: Graphene oxide composite system, application comparative example

[0099] (1) Disperse graphene oxide and polyacrylonitrile uniformly in DMF, with a mass ratio of graphene oxide to polyacrylonitrile of 5:5; the solid content of the mixed solution is 1%.

[0100] (2) Use a Mayer rod to coat the graphene oxide and polyacrylonitrile mixed solution on a PP substrate in the form of a 20 um film. When the mass content of the solvent in the film is 97%, insert the substrate into water at an angle of 30°.

[0101] (3) Transfer the composite film to isopropanol using a filter screen, and after soaking, transfer the film and substrate out, and after drying, the film automatically detaches and is collected, to obtain a self-supporting composite film.

[0102] (4) The ultra-thin film obtained in step (3) is 1200 ℃ high-temperature sintered, and finally a graphene-based carbon film of about 150 nm is obtained.

[0103] The film contains a high number of defects and the graphite structure is imperfect, with ID / IG greater than 0.01, AB content of 5%, and total carrier duration of 6 ps. The mechanical properties are poor, with elongation at break of 1.2%. After being fixed and installed, the beam current through the stripping film does not change significantly, and it can be installed and used. The use of 107Ag- The ion beam (160 nA, beam spot is Ф8 mm) was tested for film service life. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the 50% decrease of the ion beam intensity after the carbon film was stripped was recorded. It was found that the service life was 30 min, and the service life was shorter.

[0104] Comparative Example 7: Test of traditional carbon film, using Comparative Example 6

[0105] A carbon stripping film was prepared by an alternating carbon arc method. The steps are as follows,

[0106] (1) Select a suitable glass sheet as a smooth substrate, and clean the glass sheet;

[0107] (2) Spin the release agent, place the glass sheet with the spin-coated release agent into the vacuum device, and perform film plating by the alternating carbon arc method. The thickness is monitored by a film thickness monitor. A carbon stripping film with a thickness of about 200 nm is prepared;

[0108] (3) Take out the plated glass sheet for demolding to obtain a self-supporting carbon stripping film;

[0109] (4) Fix the self-supporting carbon stripping film to a special target frame and install it on the stripping device in the accelerator.

[0110] The film contains defects, the graphite structure is imperfect, the ID / IG is greater than 0.01, the AB content is 14%, and the total carrier duration is 8.5 ps. At the same time, the mechanical properties are poor, and the elongation at break is 2.1%. After fixing and installing, the beam current through the stripping film has no obvious change, and it can be installed and used. The 107Ag - The ion beam (160 nA, beam spot is Ф8 mm) was tested for film service life. Under the condition that the incident flow intensity was constant, the time from the start of irradiation to the 50% decrease of the ion beam intensity after the carbon film was stripped was recorded. It was found that the service life was 40 min, and the service life was shorter. At the same time, the arc instrument equipment is expensive, and the price of high-crystalline carbon is not cheap, and the cost is high.

[0111] Comparative Example 8: Test of diamond-like carbon film, using Comparative Example 6

[0112] A carbon stripping film was prepared by a magnetic filter cathode vacuum arc technology. The steps are as follows,

[0113] (1) Select a P-type single crystal silicon wafer, clean and dry;

[0114] (2) Spin the release agent, place the spin-coated silicon wafer on the sample clamp table in the vacuum chamber, and deposit by the magnetic filter cathode vacuum arc technology. During deposition, the workpiece disc always rotates (30 r / min) and revolves (15 r / min). A diamond-like carbon stripping film with a thickness of about 200 nm is prepared;

[0115] (3) The silicon wafer is taken out for demolding to obtain a self-supporting diamond-like peeling film;

[0116] (4) The self-supporting diamond-like peeling film is fixed into a special target frame and installed on a peeling device in an accelerator.

[0117] The film contains defects and the graphite structure is imperfect, the ID / IG is greater than 0.01, the AB content is 10%, and the total carrier duration is 7 ps. However, the mechanical property is good, the elongation at break is 6.2%. After being fixed and installed, the beam current through the peeling film does not change obviously, and the peeling film can be installed and used. The film is used for peeling. 107 Ag - The film is tested by an ion beam (160 nA, beam spot is Φ8 mm) for service life. In the case that the incident current is unchanged, the time from the start of irradiation to the decrease of the ion beam current by 50% after peeling through the carbon film is recorded. It is found that the service life is 90 min, and the service life is short. At the same time, the magnetic filtering arc instrument is expensive, and the diamond-like film is expensive, so the cost is high.

[0118] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments according to the technical essence of the present application, which does not depart from the technical solution of the present application, still belongs to the scope of the technical solution of the present application.

Claims

1. Use of a freestanding self-supporting graphene film as a carbon stripper film for a heavy ion accelerator, characterized in that, The ID / IG of the graphene film is less than 0.01, and the AB structure content is more than 90%; the graphene film is prepared by the following method: (a1) preparing graphene oxide into a graphene oxide aqueous solution with a concentration of 0.5-10 ug / mL, and filtering into a film on an aluminum oxide (AAO) substrate; (a2) reducing the graphene oxide film on the AAO film by high-temperature fumigation with 85°C hydroiodic acid for 12 hours to obtain a reduced graphene oxide film; (a3) heating and sublimating camphor to uniformly adsorb on the surface of the reduced graphene oxide film, and then cooling at room temperature, so that the reduced graphene oxide film automatically separates from the AAO film; (a4) volatilizing the camphor from the obtained reduced graphene oxide film to obtain a self-supporting reduced graphene oxide film; repairing defects after high-temperature sintering to obtain a graphene film with a thickness of less than or equal to 50 nm.

2. Use of the freestanding self-supporting graphene film according to claim 1 as a carbon stripper film for a heavy ion accelerator, characterized in that, The size of the graphene oxide sheet is 30 um-100 um.

3. Use of the freestanding self-supporting graphene film according to claim 1 as a carbon stripper film for a heavy ion accelerator, characterized in that, The temperature of the high-temperature sintering is greater than or equal to 2800 ℃.

4. Use of the freestanding self-supporting graphene film according to claim 1 as a carbon stripper film for a heavy ion accelerator, characterized in that, The porosity of the AAO film in step (a1) is not less than 50%.

5. Use of a freestanding self-supporting graphene film as a carbon stripper film for a heavy ion accelerator, characterized in that The ID / IG of the graphene film is less than 0.01, and the AB structure content is more than 90%; the graphene film is prepared by the following method: (b1) uniformly dispersing graphene oxide and graphitizable polymer in a readily soluble solvent to form a mixture, and uniformly coating the mixture on a substrate to form a composite film; (b2) inserting the substrate into deionized water at a certain angle, and peeling the composite film from the substrate; (b3) using a porous substrate to fish out the composite film and transfer it to a readily volatile solvent; (b4) after soaking, the film and the porous substrate are transferred out, and after drying, the film automatically separates and is collected to obtain a self-supporting graphene oxide nanofilm; (b5) high-temperature sintering the graphene oxide nanofilm obtained in step (b4) to obtain a graphene film with a thickness of greater than 50 nm.

6. Use of the freestanding self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The size of the graphene oxide sheet is 30 um-100 um.

7. Use of the freestanding self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The temperature of the high-temperature sintering is greater than or equal to 2800 ℃.

8. Use of the freestanding self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The graphitizable polymer in step (b1) is polyacrylonitrile (PAN), polyimide (PI), or mesophase pitch polymer; the mass ratio of the graphene oxide to the graphitizable polymer is 7:3-5:5; the readily soluble solvent is dimethylformamide (DMF), dimethylacetamide (DMAC), or N-methyl pyrrolidone (NMP); and the solid content of the mixture is 1wt%-1.5wt%.

9. Use of the freestanding self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The substrate in step (b1) is a flat substrate of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), silicon dioxide (SiO2), a silicon wafer, or aluminum oxide.

10. Use of the free-standing, self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The insertion angle in step (b2) is between 0-45°, excluding the end values.

11. Use of the freestanding self-supporting graphene film according to claim 5 as a carbon stripper film for a heavy ion accelerator, characterized in that, The readily volatile solvent in step (b3) is a solvent with a small surface tension, such as ethanol, isopropyl alcohol, or ethyl acetate.

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