Traditional Culture Encyclopedia - Traditional culture - Why can lead plate prevent radiation? Why can Shaanxi lead plate prevent radiation well?

Why can lead plate prevent radiation? Why can Shaanxi lead plate prevent radiation well?

1 First of all, we know what ionizing radiation is.

Ionizing radiation refers to rays with short wavelength, high frequency and high energy. Ionizing radiation can ionize at least one electron from an atom or molecule. Ionizing radiation is a general term for all kinds of radiation that can cause ionization of substances. There are many kinds of high-speed charged particles, such as α particles, β particles and protons, and uncharged particles, such as neutrons, X-rays and γ-rays.

Secondly, we should know the properties of various rays in ionizing radiation.

Alpha ray

Alpha rays are a stream of charged particles, which are easily ionized wherever they go. Alpha rays have strong ionization energy and can be used. It also brings some harm, and it has great destructive ability to the tissues in the human body. Because of its large mass and poor penetration ability, its range in the air is only a few centimeters, which can be blocked by a piece of paper or healthy skin.

β ray

β -ray is also a kind of high-speed charged particle, its ionization power is much less than α-ray, but its penetration power is greater than α-ray, but its range with X and γ-ray is shorter than β-ray, so it is easily absorbed by aluminum foil, plexiglass and other materials.

X-rays and gamma rays

X-rays and gamma rays are basically the same in essence, both are electromagnetic waves, and there is no wavelength of radio waves. They are short in wave length, strong in penetration, long in range and dangerous, and must be shielded.

3] Third, we need to know the principle of radiation protection.

Shielding protection

The principle of shielding protection is that the intensity of radiation will be weakened when it contains penetrating substances, and shielding substances with a certain thickness can weaken the intensity of radiation. Setting a shield (shielding material) with sufficient thickness between the radiation source and the human body can reduce the radiation level, reduce the dose people receive at work to below the maximum allowable dose, ensure personal safety and achieve the purpose of protection.

The key point of shielding protection is to place a shielding material that can effectively absorb radiation between the radiation source and the human body. The commonly used shielding materials for X-rays are lead plate, concrete wall, steel plate, or barium cement (cement plus barium sulfate-also called barite powder) wall.

Any substance can block nuclear radiation. But the difference is that the blocking ability is different.

Blocking ability mainly depends on two aspects.

1) atomic number.

2) Density of matter.

The higher the atomic number, the greater the density of matter, and the gap between atoms and molecules is smaller than the wavelength of X-rays and γ-rays, so it cannot penetrate. The more atoms with the same volume, the easier it is for α-particle flow and β-particle flow to collide with atoms and change direction. This will play a role in preventing radiation.

Finally, we need to know the nature of lead.

Lead is a metallic chemical element with chemical symbol Pb (Latin plum Lead) and atomic number 82. It is the non-radioactive element with the largest atomic weight and the cheapest element with the largest density. ? Other elements are heavier, denser, more expensive or radioactive than lead, so it is best to use lead plate.

The radiation protection performance of Shaanxi lead plate is best to brag B, the essence is that the thicker the lead plate, the better the radiation protection effect.