What are the basic methods of radiation protection

With the continuous development of science and technology, we have to deal with computers and mobile phones all the time in our lives, which are also part of the sources of radiation. Some people are affected by radiation every day due to the particularity of their work. If they are in this environment for a long time, people's health and safety will be affected. In order to reduce the radiation to the human body, radiation protection is now studied, mainly including radiation protection standards, technology, and evaluation and self-management.

introduce

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 radiation that can cause ionization of matter. There are many types of radiation. High-speed charged particles include alpha particles, beta particles, and protons, and uncharged particles include neutrons as well as X-rays and gamma rays.

Electromagnetic radiation, also known as electronic smog, consists of electrical and magnetic energy that are transferred together through space. This energy is generated by the movement of electric charges. For example, the moving charges emitted by a radio frequency antenna that is transmitting a signal will generate electromagnetic energy. The electromagnetic "spectrum" includes all forms of electromagnetic radiation, from extremely low frequency electromagnetic radiation to extremely high frequency electromagnetic radiation. In between there are radio waves, microwaves, infrared rays, visible light and ultraviolet light. The radio frequency portion of the electromagnetic spectrum is generally defined as radiation with frequencies from about 3 kHz to 300 GHz.

Radiation characteristics

Alpha rays

Alpha rays are a stream of charged particles. Because of their charge, they can easily cause ionization wherever they go. Alpha rays have a strong ionizing ability, and this property can be utilized. It also brings certain damage and has great destructive ability to human body tissues. Due to its large mass and poor penetration ability, its range in the air is only a few centimeters, and it can be blocked by a piece of paper or healthy skin.

Beta rays

β rays are also a kind of high-speed charged particles. Their ionization ability is much smaller than that of α rays, but their penetrating ability is greater than that of α rays. However, compared with X-rays and γ-rays, β rays have a shorter range and are easily absorbed by materials such as aluminum foil and plexiglass.

X-rays and gamma rays

X-rays and gamma rays have roughly the same properties. They are non-electrical short-wavelength electromagnetic waves. They have short wavelengths, strong penetrating power, long range, are dangerous, and must be shielded.

Radiation Hazards

In the work of exposure to ionizing radiation, if the protective measures are not appropriate, the operating procedures are violated, and the dose of radiation to the human body exceeds a certain limit, harmful effects may occur.

use. Under the influence of electrical radiation, the degree of the body's reaction depends on the type, dose, irradiation conditions and sensitivity of the ionizing radiation. Ionizing radiation can cause radiation sickness, which is a systemic reaction of the body. Almost all organs and systems undergo pathological changes, but the changes in the nervous system, hematopoietic organs, and digestive system are the most obvious. The damage caused by ionizing radiation to the body can be divided into acute radiation damage and chronic radiation damage. Exposure to a certain dose of radiation in a short period of time can cause acute damage to the body, which is commonly seen in nuclear accidents and radiation therapy patients. Exposure to a certain dose of radiation over a long period of time can cause chronic radiation damage, such as skin damage, hematopoietic disorders, leukopenia, and impaired fertility. In addition, radiation can cause cancer and fetal death and deformity.

Protection standards

Radiation dosimetry studies radiation dose and its measurement. Radiation protection standards are the basis for implementing radiation protection. Currently, all countries formulate corresponding standards based on the recommendations of the International Commission on Radiological Protection (ICRP) and in combination with their own national conditions [1]. Radiation protection evaluation includes evaluation of radiation equipment, radiation safety, and radiation pollution to the environment.

Protection elements

The three elements of radiation protection are distance, time and shielding, or the main methods of radiation protection are time protection, distance protection and shielding protection. The specific principles are as follows:

Time protection

The principle of time protection is that the cumulative dose received by people in the radiation field is proportional to the time. Therefore, if the exposure rate remains unchanged, shortening the exposure time can reduce the dose received. Or, if people work within a limited time, the radiation dose they receive may be below the maximum allowable dose, ensuring personal safety (this method is only used in extraordinary circumstances) and achieving the purpose of protection.

The key point of time protection is to minimize the human body's contact time with radiation (shorten the time the human body is exposed to radiation).

Distance protection

Distance protection is an effective method of external radiation protection. The basic principle of distance protection is to first regard the radiation source as a point source. The exposure and absorbed dose of a point in the radiation field are inversely proportional to the square of the distance between the point and the source. We call this law the inverse square law, that is, the radiation intensity varies inversely with the square of the distance (when the source radiation intensity is constant, the dose rate or exposure is inversely proportional to the square of the distance from the source). Increasing the distance between the radiation source and the human body can reduce the dose rate or exposure, or working at a certain distance so that the radiation dose people receive is below the maximum allowable dose can ensure personal safety. So as to achieve the purpose of protection.

The key point of distance protection is to increase the distance between the human body and the radiation source as much as possible.

Shielding protection

The principle of shielding protection is: the intensity of radiation will weaken when penetrating matter. Shielding material of a certain thickness can weaken the intensity of radiation. By setting a sufficiently thick shield (shielding material) between the radiation source and the human body, the radiation level can be reduced, so that the dose people receive at work is reduced to below the maximum allowable dose, ensuring personal safety and achieving 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. Common shielding materials for X-rays are lead sheets and concrete walls, steel plates, or barium cement (cement with barium sulfate - also called barite powder - added) walls.

Ionizing radiation sign

Specifications of ionizing radiation warning sign: 250*350mm. The triangle in the picture has black text on a yellow background.