Electron beam radiation biology, human cells, tissues, body fluids, such as material interaction, causes ionization of atoms or molecules, so some macromolecular structures can directly damage the body, such as protein molecular chain breaks, broken RNA or DNA, destroy some of the important significance for metabolic enzymes, and so on, and even directly damage the cell structure. In addition, the rays can ionize the water molecules widely existing in the body to form some free radicals, and damage the body through the indirect action of these free radicals.
The pathogenesis of radiation injury is the same as other diseases. After the pathogenic factors act on the body, they will not only cause the change of molecular level and cell level, but also produce a series of secondary effects, which eventually lead to the disorder of organ level or even the change of overall level. Signs and symptoms of radiation injury may appear in clinical practice.
Lead glass for protection is an amorphous transparent protective material, which often contains a lot of B20. Different density lead glass (3.7-6.2g / cm ') can be made according to the lead content. With the increase of the density of leaded glass, it can shield D and P radiation more effectively, and protect the leaded glass from - S9 back slip after (1-2) x1020 neutron / cm 'irradiation. At this time, silicate glass and jet glass are still in amorphous state.
In the process of heat treatment, the glass will also be unglazed, but its performance is different from that of neutron irradiation. Under neutron irradiation, the density of lead glass for protection decreased. After irradiation (8-16) X101. Neutrons per square centimeter, down 1.5%. After irradiation with 2x10z neutron / CMZ, the thermal conductivity of lead glass decreased by 38 [60,6 x].
When the absorbed dose of D irradiation reaches 1mgy, the irradiation colouring of mercury lamp almost disappears. After repeated irradiation of 1mgy, the optical density was higher than that after the first irradiation. ·Before the absorption dose of 5x10agy, the change of optical density of lead glass for protection has an exponential relationship with the absorption dose, and then a linear relationship. After irradiation, the absorption bands of Pb-B, pb-al-b and pb-al-si glasses are 825t.tm (1.5ev), which may be related to the Pb2 + and B atoms in the glass structure.
Damage to human cells, limited to the individual itself, can lead to somatic effects. The damage of germ cells will affect the offspring of the irradiated individuals and produce genetic effects. When a single or a small number of cells are damaged by radiation (mainly chromosome aberrations, gene mutations, etc.), random effects will occur. When radiation damages or destroys a large number of cells, non random effects will occur. In the development of radiation injury, the body's response plays a more important role. First, it depends on the role of the nervous system, especially the higher nerve activity, and second, it depends on the regulation of body fluids. Therefore, diseases of higher animals can not be attributed to simple or isolated processes, which involve very complex processes.