Atomic radiation is one of the most dangerous. Its consequences are unpredictable for humans. What is meant by the concept of radioactivity? What do the words “greater” or “lesser” radioactivity mean? What particles are part of various types of atomic radiation?
What is radioactive radiation?
The composition of radioactive radiation may include various particles. However, all three types of radiation belong to the same category - they are called ionizing. What does this term mean? The radiation energy is incredibly high - so much so that when the radiation reaches a certain atom, it knocks an electron from its orbit. Then the atom, which has become the target of radiation, turns into an ion, which is positively charged. That is why atomic radiation is called ionizing, whatever type it may be. High power distinguishes ionizing radiation from other types, for example, from microwave or infrared.
How does ionization occur?
To understand what may be part of radioactive radiation, it is necessary to consider in detail the ionization process. It happens as follows. An atom with magnification looks like a small poppy seed (the nucleus of an atom), surrounded by the orbits of its electrons, like a shell of a soap bubble. When radioactive decay occurs, the smallest grain - an alpha or beta particle - flies from this nucleus. When a charged particle is emitted, the charge of the nucleus also changes , which means that a new chemical substance is formed.
Particles that are part of radioactive radiation behave as follows. A grain flying off from the nucleus rushes forward with gigantic speed. On its way, it can crash into the shell of another atom and just knock an electron out of it. As already mentioned, such an atom will turn into a charged ion. However, in this case, the substance will remain the same, since the number of protons in the nucleus has remained unchanged.
Features of the process of radioactive decay
Knowledge of these processes allows us to evaluate how intense is the radioactive decay. This value is measured in becquerels. For example, if one decay takes place in one second, then they say: "The activity of the isotope is 1 becquerel." Once, instead of this unit, a unit called curie was used. It was equal to 37 billion becquerels. In this case, it is necessary to compare the activity of the same amount of substance. The activity of a certain unit mass of the isotope is called specific activity. This value is inversely proportional to the half-life of one or another isotope.
Characterization of radioactive radiation. Their sources
Ionizing radiation can occur not only in the case of radioactive decay. The sources for radioactive radiation can be: the fission reaction (as a result of an explosion or inside an atomic reactor), the synthesis of so-called light nuclei (occurs on the surface of the Sun, other stars, as well as in a hydrogen bomb), as well as various accelerators of charged particles. All these radiation sources have one thing in common - a powerful level of energy.
What particles are included in alpha radiation?
The differences between the three types of ionizing radiation - alpha, beta and gamma - are in their nature. When these radiations were discovered, no one had any idea what they might be. Therefore, they were simply called letters of the Greek alphabet.
As their name implies, alpha rays were discovered first. They were part of radioactive radiation during the decay of heavy isotopes such as uranium or thorium. Their nature has been determined over time. Scientists have found that alpha radiation is quite heavy. In the air, it can not overcome even a few centimeters. It turned out that the composition of radioactive radiation can include nuclei of helium atoms. This is what applies to alpha radiation.
Its main source is radioactive isotopes. In other words, it represents positively charged “sets” of two protons and the same number of neutrons. In this case, they say that the composition of radioactive radiation includes a- particles, or alpha particles. Two protons and two neutrons form the nucleus of helium, characteristic of alpha radiation. For the first time in humanity, such a reaction was able to get E. Rutherford, engaged in the conversion of nitrogen nuclei into oxygen nuclei.
Beta radiation, discovered later, but no less dangerous
Then it turned out that the composition of radioactive radiation can include not only helium nuclei, but simply ordinary electrons. This is true for beta radiation - it consists of electrons. But their speed is much greater than the speed of alpha radiation. This type of radiation also has a lower charge than alpha radiation. Beta particles “inherit” different charges and different speeds from the parent atom.
It can reach from 100 thousand km / s up to the speed of light. But in the open air, beta radiation can spread to several meters. Their penetrating ability is very small. Beta rays cannot overcome paper, fabric, a thin sheet of metal. They only penetrate into this matter. However, exposure without protection can cause burns to the skin or eyes, as is the case with ultraviolet rays.
Negatively charged beta particles are called electrons, and positively charged are called positrons. A large amount of beta radiation is very dangerous for humans and can lead to radiation sickness. Much more dangerous may be getting inside the radionuclides.
Gamma Radiation: Composition and Properties
The next was discovered gamma radiation. In this case, it turned out that the composition of the radiation can include photons with a certain wavelength. Gamma radiation is like ultraviolet, infrared rays of radio waves. In other words, it is electromagnetic radiation, but the energy of the photons entering it is very high.
This type of radiation has an extremely high ability to penetrate any obstacles. The denser the material standing in the way of this ionizing radiation, the better it can contain dangerous gamma rays. Lead or concrete is most often chosen for this role. In the open air, gamma radiation can easily travel hundreds and thousands of kilometers. If it affects a person, then this leads to damage to the skin and internal organs. By its properties, gamma radiation can be compared with x-ray. But they differ in their origin. After all, x-rays are received only in artificial conditions.
What is the most dangerous radiation?
Many of those who have already studied which rays are part of radioactive radiation are convinced of the danger of gamma rays. After all, it is they who can easily overcome many kilometers, destroying the lives of people and leading to a terrible radiation sickness. In order to protect themselves from gamma rays, nuclear reactors are surrounded by huge concrete walls. Small pieces of isotopes are always placed in containers made of lead. However, the main danger to humans is the dose of radiation.
Dose - this is the amount that is usually calculated taking into account the body weight of a person. For example, for one patient, a dose of 2 mg will be appropriate. For another, the same dose may have an adverse effect. The dose of radiation is also evaluated. Its danger is determined by the absorbed dose. To determine it, first measure the amount of radiation that has been absorbed by the body. And then this amount is compared with body weight.
Dose of radiation - a criterion of its danger
Different types of radiation can cause different harm to living organisms. Therefore, one must not confuse the penetrating power of various types of radioactive radiation and their damaging effect. For example, when a person does not have the opportunity to protect himself from radiation, alpha radiation is much more dangerous than gamma rays. After all, it contains heavy hydrogen nuclei. And such a type as alpha radiation, shows its danger only when it gets into the body. Then internal irradiation occurs.
So, the composition of radioactive radiation can include three types of particles: these are helium nuclei, ordinary electrons, and also photons with a certain wavelength. The danger of a particular type of radiation is determined by its dose. The origin of these rays does not matter. For a living organism, there is absolutely no difference where radiation came from: be it an X-ray machine, the Sun, a nuclear power plant, a radon resort, or an explosion. Most importantly, how many hazardous particles were absorbed.
Where does atomic radiation come from?
Along with the natural radiation background, human civilization is forced to exist among many artificially made sources of dangerous ionizing radiation. Most often it is the result of terrible accidents. For example, the disaster at the Fukushima-1 nuclear power plant in September 2013 led to the leakage of radioactive water. As a result of this, the content of strontium and cesium isotopes in the environment has increased significantly.