The thickness of boron-polyethylene board is 2cm-30cm. Its technical field is nuclear technology application of ionizing radiation protection. Boron-polyethylene board is used for shielding fast neutrons of neutron radiation field, neutron and Y mixed radiation field in the field of ionizing radiation protection, to prevent radiation harm and damage caused by neutron radiation to occupational workers and the public.
In order to improve the shielding effect of boron polyethylene on fast neutron and solve the problem that it is difficult to produce boron polyethylene board commercially in China, a boron-containing polyethylene board with boron content of 8% was developed. In terms of the principle of shielding fast neutrons, since the rest mass of neutrons is 1.0086649U, while that of hydrogen atoms (i.e. protons) is 1.007825 U [1], the atomic mass of neutrons is close to that of hydrogen atoms. Therefore, when the fast neutron collides with the hydrogen nuclei in the shielding body, It is easiest to lose energy by transferring it to the nucleus of the hydrogen atom, slowing down fast neutrons to slow neutrons and thermal neutrons. The more hydrogen the shielding body contains, the stronger the moderating effect will be. Among the hydrogen content of commonly used neutron shielding materials, the hydrogen content of polyethylene is the highest, up to 7.92x IO22 atoms /cm3 gas. Therefore, polyethylene is the best moderator for shielding fast neutrons. After fast neutrons are slowed down into thermal neutrons, shielding materials with large thermal neutron absorption cross section without high-energy Y radiation are needed to absorb thermal neutrons, so as to achieve the purpose of shielding fast neutrons completely. Due to the high thermal neutron absorption cross section of (3840 lL)X10_24cm2[3], and the abundance of kiB in natural boron is 18.98% [3], which is easy to obtain, boron-containing materials are good absorbent for shielding thermal neutrons.
Neutron radiation protection in nuclear power plants, medium (high) energy accelerators, atomic reactors, nuclear submarines, medical accelerators, neutron therapy equipment and other places.
Post time: May-31-2022
