The first object of radiation protection equipment is: α - ray alpha particle is the nucleus of helium-4 with high energy. Due to the Coulomb field effect and elastic collision, the energy of alpha particles is often consumed to absorb other substances. Therefore, the protection against radiation is relatively simple, and a piece of paper can basically prevent it. However, it does great harm to people in close range. Alpha particle internal irradiation will consume all the energy in a short distance, so it damages the cells and tissues exposed to short distance irradiation seriously.

射线防护器材之防护对象二：β射线 β粒子实质是高速运动的电子束，带有一个负电荷(对正电子是一个正电荷)，质量为质子或中子的1/1837。β射线的穿透能力一般，介于α、γ射线之间。

Protection object 2: beta ray beta particle is essentially a high-speed moving electron beam with a negative charge (a positive charge to a positron), with a mass of 1 / 1837 of a proton or neutron. The penetration ability of β - ray is between α - ray and γ - ray.

由于β射线与原子量较大的物质作用时容易产生轫致辐射，所以对于活度较大的β放射源，一般会选择有机玻璃等轻质材料进行防护，然后再选择原子量较大的物质进行屏蔽。对β射线的防护既要考虑内照射，又要考虑外照射。

Since bremsstrahlung is easy to be produced when β - ray interacts with substances with large atomic weight, for beta radiation sources with large activity, light materials such as plexiglass are generally selected for protection first, and then materials with larger atomic weight are selected for shielding. Both internal and external irradiation should be considered in the protection of β - ray.

射线防护器材之防护对象三：γ射线γ射线实质是高能光子束，由于光子不带电，且其静止质量为0，所以不太容易损失能量。γ射线只有在与物质相互作用发生光电效应、康普顿散射、电子对湮灭三种效应时才会损耗能量。

Protection object 3: gamma ray gamma ray is essentially a high-energy photon beam. Because the photon is not charged and its static mass is 0, it is not easy to lose energy. Only when the interaction between gamma ray and matter occurs photoelectric effect, Compton scattering and electron pair annihilation, will the energy be lost.

γ射线的穿透能力较强，所以一般会选择用原子序数较高的材料(如铅、贫铀、钨)或厚度较大的混凝土、水等进行屏蔽。除此之外，能量越高的γ射线越难防护。对γ射线的防护主要考虑外照射因素，但由于其通常还会伴随着α、β衰变的发生，所以内照射防护也不能忽视。

Because of the strong penetration ability of gamma ray, materials with higher atomic number (such as lead, depleted uranium, tungsten) or concrete and water with large thickness are generally selected for shielding. In addition, the higher the energy, the more difficult it is to protect. The protection of gamma ray mainly considers the external radiation factor, but because it is usually accompanied by α, β decay, so the internal radiation protection can not be ignored.