Radioactive or ionizing radiation greatly affects living organisms. People are constantly exposed to radiation in small amounts that do not cause serious harm to he alth. However, stronger radioactive radiation leads to serious illnesses and a threat to life. Therefore, a special system of coefficients has been developed to measure the radiation dose.
What is radioactive radiation?
Ionizing radiation is the energy produced by the atoms of radioactive substances. Radiation sources are:
- natural origin - radioactive decay, cosmic rays, thermonuclear reactions;
- man-made - nuclear reactor, nuclear fuel, atomic bomb, medical equipment (eg X-ray machine).
Types of radioactivity
There are three types of radioactivity by origin:
- natural - inherent in heavy radioactive elements;
- artificial - intentionally created by man with the help of decay reactions andfusion of atomic nuclei;
- induced - observed in substances that have been heavily irradiated and themselves become a source of radiation.
Types of radiation
There are three types of ionizing radiation: alpha rays, beta rays and gamma rays.
Alpha radiation has a low penetrating power. The beams are a stream of helium nuclei. Almost any barrier can protect against alpha rays: clothes, skin, a sheet of paper. It is almost impossible to receive a dangerous dose of radiation in this case, if you follow the precautions.
Beta radiation is more dangerous to the body. It consists of a stream of electrons. Its penetrating power is much higher than that of alpha rays. The electron flow moves at high speed, so the radiation is able to pass through clothes and skin, penetrating the body and causing damage to he alth.
Gamma radiation is the most dangerous. This is electromagnetic radiation with an extremely short wavelength. Such rays have an enormous penetrating power and are detrimental to a living organism. If the absorbed dose of such radiation exceeds the allowable threshold, it can lead to serious illness and even death.
How is exposure measured?
To calculate the level of radiation, the concept of "absorbed dose" (D) is used. This is the ratio of the absorbed radiation energy (E) to the mass of the irradiated object (m). This value is expressed in two ways:
- in grays (Gy) - one gray is equal to the dose at whichone kilogram of matter accounts for the energy of 1 J;
- in roentgens (R) - used for x-rays and gamma rays and equals approximately 0.01 Gy.
A dose of 100 R leads to dangerous he alth effects. The lethal dose is 500 R.
The level of radiation is measured with a special dosimeter.
Equivalent dose of absorbed radiation
This value is used in assessing the destructive effect of radiation on the body. It is also called the biological dose. The equivalent dose is denoted by the letter H and is calculated by the formula: H=D x k.
K - quality factor. This value describes the impact on the body of a type of ionizing radiation (X-ray and gamma radiation).
The unit of equivalent radiation dose is called sievert (Sv). The name is given in honor of the radiophysicist Rolf Sievert, who studied the effects of radiation on living organisms. The units of millisievert (mSv) and microsievert (µSv) are also used.
An important concept is the equivalent dose rate of H. It is understood as the rate at which the dose of H accumulates in the body.
What doses are safe for the body? It has been established that the permissible equivalent dose of H, within which pathological processes in tissues and cells do not occur, is 0.5 Sv. A single lethal dose is 6-7 Sv.
A person during his life receives microdoses of radiation from natural and artificial sources. On average, the annual doses of absorbed radiation are 2mSv.
Danger of ionizing radiation
What happens to the body when irradiated? The main danger of radioactive radiation is that its effect goes almost unnoticed. Ionizing rays do not cause pain, are not visible visually and with the help of other senses. Therefore, a person may not even realize that they are being exposed to dangerous radiation until it is too late.
Even a small exposure is dangerous for living organisms. Radiation ionizes the atoms and molecules in the cells of the body. The chemical activity of cells changes, and this leads to radioactive damage to organs and tissues. Their functioning is disrupted.
The most radiation affects rapidly dividing cells. The circulatory system and bone marrow begin to suffer first, then the digestive system and other organs.
Also, radiation has a detrimental effect on the genes in the chromosomes, leading to severe hereditary diseases or reproductive dysfunction. The most common ailment is the so-called radiation sickness.
At high equivalent doses of radiation, it can develop already in the first minutes and hours after exposure. Acute radiation sickness is accompanied by symptoms such as nausea, vomiting, fever, and hemorrhages.
Often this disease is inherited. Many descendants of the victims of Hiroshima, Nagasaki and the Chernobyl accident still feel the effects of radiation sickness.
Benefits of ionizing radiation
Radioactive radiationdoes more than just harm. Under certain conditions, you can also benefit from it, which is actively used in various industries.
Small doses of radiation are used in medicine to treat cancer. Cells in malignant tumors are destroyed by ionizing radiation, so radiation therapy is used in the treatment of cancer. Also in medicine, special preparations created on the basis of radioactive substances are used. Ionizing rays contribute to the sterilization of medical devices.
The use of X-ray machines is invaluable in diagnosing diseases and determining the degree of damage.
Ionizing radiation is used to make smoke detectors, to screen luggage at airports and to ionize the air.
Radiation is also used in industries such as metallurgy, light industry, food industry, construction industry, agriculture.
Protection from radiation
When working with sources of ionizing radiation, precautions must be taken to protect the body from injury.
A simple but effective way to protect yourself from radiation is to move away from the source of radiation. Firstly, the radiation is absorbed by the air, and secondly, when moving away from the source, the radiation intensity decreases in proportion to the square of the distance.
If it is impossible to remove from the source, other means of protection must be used. Clothing made of special materials will become an obstacle toradiation paths.
Substances that absorb radiation well are lead and graphite.
Summing up, we can note the following
- radioactive radiation is of three types: alpha, beta and gamma rays;
- radiation strength changes in Grays and Roentgens;
- The equivalent dose unit is Sievert.
Radiation causes great harm to the body, but in prescribed doses and when used correctly, it can serve the benefit of mankind.
