The thickness of boron-containing polyethylene board is 2cm-20cm. The technical field of the invention is ionizing radiation protection for nuclear technology applications. Boron-containing polyethylene sheets are used in the field of ionizing radiation protection to shield neutron radiation fields, fast neutrons in neutron and Y mixed radiation fields, and prevent neutron radiation from causing radiation hazards and damage to occupational workers and the public.
Boron-containing polyethylene sheet In order to improve the shielding effect of boron-containing polyethylene on fast neutrons and solve the problem that domestic boron-containing polyethylene sheets are difficult to commercialize large-scale production, a boron-containing polyethylene sheet with a boron content of 8% was developed. As far as the principle of shielding fast neutrons is concerned, since the rest mass of neutrons is 1.0086649U, and the rest mass of hydrogen atoms (that is, protons) is 1.007825u[1], the atomic mass of neutrons is similar to that of hydrogen atoms, Therefore, when fast neutrons collide elastically with hydrogen nuclei in the shield, it is easiest to transfer their energy to hydrogen nuclei and lose energy, thereby slowing fast neutrons into slow neutrons and thermal neutrons. The more hydrogen content in the shielding body, the stronger the moderation effect. Among the hydrogen content of commonly used neutron shielding materials, polyethylene has the highest hydrogen content, which can reach 7.92X IO atoms/cm3 gas. Therefore, polyethylene is a The best moderator for shielding fast neutrons. After the fast neutrons are moderated into thermal neutrons, a shielding material with a large absorption cross section for thermal neutrons without producing high-energy gamma radiation can absorb thermal neutrons, so as to achieve the purpose of completely shielding fast neutrons. Due to its high thermal neutron absorption cross section, which is (3840±11)×10_24cm2[3], and the abundance of kiB in natural boron is 18.98%[3], it is easy to obtain, so boron-containing materials are shielding Good absorber of thermal neutrons.
Application field of boron-containing polyethylene sheet Neutron radiation protection in nuclear power plants, medium (high) energy accelerators, atomic reactors, nuclear submarines, medical accelerators, neutron therapy equipment and other places.
