/ / Alpha, gamma, beta radiation. Properties of particles alpha, gamma, beta

Alpha-, gamma, beta radiation. Properties of particles alpha, gamma, beta

What is a radionuclide?Do not be afraid of this word: it simply means radioactive isotopes. Sometimes in speech you can hear the words "radionuclide", or even less literary version - "radionucleotide". The correct term is precisely a radionuclide. But what is radioactive decay? What are the properties of different types of radiation and how do they differ? About everything - in order.

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Definitions in radiology

Since the time when the first explosion occurredatomic bomb, many concepts from radiology have changed. Instead of the phrase “atomic boiler” it is customary to say “atomic reactor”. Instead of the phrase "radioactive rays" use the expression "ionizing radiation." The phrase "radioactive isotope" is replaced by "radionuclide".

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Long-lived and short-lived radionuclides

Alpha, beta and gamma radiation accompanythe process of decay of the atomic nucleus. What is the half-life? The nuclei of radionuclides are not stable - this is what distinguishes them from other stable isotopes. At some point, the process of radioactive decay starts. In this process, radionuclides are converted into other isotopes, during which alpha, beta and gamma rays are emitted. Radionuclides have different levels of instability — some of them decay for hundreds, millions, or even billions of years. For example, all uranium isotopes that are found in nature are long-lived. There are such radionuclides, which disintegrate within seconds, days, months. They are called short-lived.

Emission of alpha, beta and gamma particles accompaniesnot any decay. But in fact, radioactive decay is accompanied only by the release of alpha or beta particles. In some cases, this process is accompanied by gamma rays. Pure gamma radiation does not occur in nature. The greater the rate of decay of a radionuclide, the higher its level of radioactivity. Some believe that in nature there are alpha, beta, gamma and delta decay. This is not true. Delta decay does not exist.

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Radioactivity units

However, how is this value measured?Measurement of radioactivity allows us to express the decay intensity in numbers. The unit of measurement of radionuclide activity is Becquerel. 1 becquerel (Bq) means that 1 decay occurs in 1 sec. Once for these measurements a much larger unit of measurement was used - curie (Ci): 1 curie = 37 billion becquerels.

Naturally, you need to match the samemass of a substance, for example, 1 mg of uranium and 1 mg of thorium. The activity of a given mass unit of a radionuclide is called specific activity. The longer the half-life, the lower the specific radioactivity.

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Which radionuclides are a big danger?

This is quite a provocative question.On the one hand, short-lived ones are more dangerous, because they are more active. But after all, after their disintegration, the very problem of radiation loses its relevance, while the long-lived ones pose a danger for many years.

The specific activity of radionuclides can be comparedwith weapon. What weapon will be more dangerous: what makes fifty shots per minute, or what shoots once in half an hour? This question cannot be answered - it all depends on what the caliber of the weapon is, how it is charged, whether the bullet reaches the target, what the damage will be.

Differences between types of radiation

Alpha, gamma and beta types of radiation canattributed to the "caliber" of weapons. These radiations have both the general, and distinctions. The main common feature - all of them are classified as hazardous ionizing radiation. What does this definition mean? The energy of ionizing radiation has extraordinary power. Getting into another atom, they knock an electron out of its orbit. When a particle is emitted, the nuclear charge changes — a new substance is formed.

Nature alpha rays

And the common thing between them is that gamma,beta and alpha radiation have a similar nature. The very first alpha rays were discovered. They were formed during the decay of heavy metals - uranium, thorium, radon. Already after the discovery of alpha rays, their nature was clarified. They turned out to be flying with great speed the helium nuclei. In other words, these are heavy “sets” of 2 protons and 2 neutrons with a positive charge. In the air, alpha rays travel a very small distance - no more than a few centimeters. Paper or, for example, the epidermis completely stop this radiation.

alpha beta and gamma rays

Beta radiation

Beta particles discovered by the following provedordinary electrons, however, possessing tremendous speed. They are much smaller than alpha particles, and also have a lower electrical charge. Beta particles easily penetrate various materials. In the air, they overcome the distance to a few meters. The following materials can hold them: clothes, glass, thin metal sheet.

Properties of gamma rays

This type of radiation has the same nature asultraviolet radiation, infrared rays or radio waves. Gamma rays are photon radiation. However, with extremely high speed photons. This type of radiation penetrates materials very quickly. Lead and concrete are commonly used to hold it. Gamma rays can travel thousands of kilometers.

Danger myth

Comparing alpha, gamma and beta radiation, peoplegamma rays are usually considered the most dangerous. After all, they are formed during nuclear explosions, travel hundreds of kilometers and cause radiation sickness. All this is true, but not directly related to the danger of the rays. Since in this case they speak precisely about their penetrating ability. Of course, alpha, beta and gamma rays are different in this respect. However, the danger is not assessed by penetrating ability, but by the absorbed dose. This indicator is calculated in joules per kilogram (J / kg).

Таким образом, доза поглощенного излучения measured by fraction. Its numerator contains not the number of alpha, gamma and beta particles, but energy. For example, gamma radiation can be hard and soft. The latter has less energy. Continuing the weapon analogy, one can say: not only the caliber of a bullet matters, but what makes a shot from a slingshot or a shotgun is also important.