Design And Performance Research Of Multi-interface Shielding Configuration For Spatial High-energy Electron In A Magnetic Field

With the rapidly development of aerospace technology,the issue of space radiation protection has drawn more and more attention.And the research on spatial high-energy electron radiation protection is particularly important for spacecraft,space station and astronaut safety.The extreme radiation environment will induce radiation damage to spacecraft facilities and radiation diseases to astronauts because of huge energy deposition.Given the increasing secondary X-rays amounts caused by bremsstrahlung and the immense mass requirement of conventional passive method,and immense magnetic flux density demand and engineering application problems of active method,a multi-interface shielding configuration for spatial high-energy electron in a magnetic field based on electron return effects was proposed.The main research contents involved were as follows.(1)We proposed a multilayer configuration that couples active method with passive method.For 20 MeV and the continuous energy spectrum of spatial high-energy electron,we compared the shielding property of the multilayer configuration with that of the corresponding passive shield.The result indicated that the former is not only superior in high-energy electron shielding property but also significantly decreases secondary X-ray transmission.In addition,the influence of magnetic flux density and number of aluminum layers on the shielding properties for multilayer systems was also investigated by building a female phantom to calculate effective dose.The shielding ability decreased with increasing magnetic flux intensity.And the thin Al layer exhibits improved electron shielding property.(2)During the operation of spacecraft,its surface may suffer the collision from space debris and meteoroid.Thus,the excellent mechanical properties are essential for shielding configuration.In order to meet the needs of mechanical properties,honeycomb and foam systems were proposed to shield against spatial high-energy electrons in a magnetic field.The shielding properties were investigated by the Monte Carlo method.For 20 MeV and the continuous energy spectrum of spatial high-energy electron,the results indicated that the honeycomb and foam systems exhibit superior shielding capability,as indicated by the lower amounts of penetrating electrons and secondary X-rays;shielding property increases with increasing magnetic flux density;a small hollow cube enhances the shielding capacity of both the honeycomb and foam structures.Compared with the honeycomb structure,the foam structure exhibits better shielding performance.(3)The mechanical properties of honeycomb and foam structure were studied by finite element method.The results of stress distribution and stress-strain curve indicated that the hollow cube size of the honeycomb and foam structure with the same mass(porosity)has no significant effect on the compress ability.A small hollow cube exhibits more uniform stress distribution.In addition,compared with foam structure,the honeycomb structure shows larger elastic modulus,higher stress platform and better compression performance.In this thesis,we have designed and investigated a multi-interface shielding configuration for spatial highenergy electron in a magnetic field,which contains multi-layer,honeycomb and foam structure.These systems do not only exhibit superior high-energy electron shielding ability and less transmitted secondary X-rays,but also reduce magnetic flux density requirements;thus,these systems may have extensive application prospects in radiation protection against spatial high-energy electrons.