Graphene Collector Materials With Tolerance To High Current Electron Beam Bombardment

High-current electron beam(HCEB)is mainly used in high-power microwave(HPM),strong laser pumping,and small-volume thermonuclear fusion reactions.The high-current electron beam collector is an important part of the high-power microwave source.The high-current electron beam will collide with the collector and lose energy,triggering a series of reactions that may degrade the performance of the system.Therefore,the development can withstand the bombardment of the high-current electron beam The collector material is an important subject.The advantages of graphene’s low atomic number and high electrical and thermal conductivity meet the needs of ideal collector materials.However,the few-layer graphene film itself cannot be self-supporting.It is usually grown on a metal substrate with a low melting point such as copper.When it is directly used as a collector,the metal substrate will be heated and melted and damaged.Assembling graphene into macroscopic materials and applying it to the electron beam collector,it is necessary to solve the problem of substrate transfer removal or direct preparation of multilayer graphene films to achieve independent self-supporting.Based on the above analysis,this article proposes two preparation schemes: one is to prepare a few-layer graphene film supported by a copper mesh substrate by selective etching;the other is to prepare self-supporting multilayer graphene by high-temperature reduction of graphene oxide film.The obtained graphene film was characterized by SEM,XPS,FTIR,Raman,XRD and other means,and its tolerance to high current electron beam bombardment was studied through a magnetic compression high-power pulse drive source platform.In the preparation of a few-layer graphene film on a copper mesh substrate,the effects of spin-on PMMA support layer,plasma etching,ultraviolet lithography,chemical etching and other processes on the morphology and structure of the few-layer graphene film were systematically studied.The results show that the copper mesh supported graphene film prepared by selective etching has a regular network structure.As the aperture of the mask pattern increases,the hole translation period decreases.After chemical etching,the thickness direction of the copper base does not With the protection of photoresist,adhesion gradually occurs between the circular holes,which makes the copper mesh unable to have sufficient support.A mask pattern with a hole diameter of 10μm and a hole translation period of 50 μm can achieve the best etching effect.In the preparation of self-supporting multilayer graphene films,the effect of thermal reduction temperature on the composition and structure of graphene films was focused on.The results show that as the heat treatment temperature increases,the resistivity of the film decreases significantly,the crystallinity increases,and the flexibility decreases.The ratio of the Raman D peak and the G peak of the film before and after reduction decreased by 5.9%,and the carbon-oxygen ratio increased by 70.6%,indicating that the oxygencontaining groups in the film were effectively eliminated by thermal reduction.The high-current electron beam bombardment test showed that the electron beam bombardment tolerance of the few graphene films on the copper mesh substrate increased with the increase of the number of graphene layers.Among them,samples with 6-10 layers of graphene have better tolerance to high current electron beam bombardment.The RGO-1 film has a poor tolerance to high current electron beam bombardment.The RGO-2 film’s tolerance to electron beam bombardment also becomes stronger with the increase of the thickness of graphene.RGO-2-a and RGO-2-b are at 400 k V,The 6800 A electron beam keeps the shape intact and exhibits good tolerance to high current electron beam bombardment.Compared with the films prepared by the two methods,the film with more graphene layers has better tolerance to high current electron beam bombardment.