Beta radiation

The nuclei of some atoms are characterized by instability, which manifests itself in their ability to transform (spontaneous decay), accompanied by the emission of radiation (ionizing radiation). The most common type of nuclear decay is beta radiation.

Radiation refers to various microparticles and physical fields that have the ability to ionize substances. It exists until its own absorption by some substance. Sources of radiation (technical nuclear installations or simply radioactive substances) are capable, in contrast to the radiation itself, of a very long time. Natural radiation is present in our lives all the time. Ionizing radiation existed before the birth of the first forms of life on Earth.

Beta radiation is a continuous stream of positrons or electrons that is emitted in beta-radioactive atomic decay. Such a decay is not peculiar to all atoms, but only to certain substances. Electrons (or positrons) are formed in nuclei in the process of conversion of neutrons into protons or vice versa. The resulting stable particles, which do not have a rest mass and charge, are called neutrinos and antineutrinos.

In the case of electron decay, a nucleus is formed, the number of protons in which increases by one, in comparison with the amount before decay. In the case of positron decay, the nuclear charge per unit decreases. In both cases, the mass number does not change.

Emitted electrons (or positrons) have different energies, ranging from zero to the maximum limiting energy Em (equal to several megaelectronvolts).

Beta-radiation has a continuous spectrum of energy. The energy levels of the nucleus are discrete in this case. This means that with each subsequent decay, a new energy will be released. This continuity of the emission spectra is explained by the fact that during decay, excess atomic energy is able to be distributed differently between the emitted particles. Therefore, the spectrum of neutrinos that are emitted during decay is also characterized by continuity.

Beta radiation is measured by beta spectrometers, special beta counters and ionization chambers

Radioactive isotopes, which are accompanied by radiation of this type, are called beta emitters. These include isotopes of sulfur (S35), phosphorus (P32), calcium (Ca45), etc. If decay is not accompanied by gamma radiation, it is called pure beta radiation.

Many radiators (P32, C14, Ca45, S35, etc.) are used in radioisotope diagnostics and are used for experimental purposes.

Passing through the substance, beta rays (beta radiation) interact with the nuclei of its atoms and electrons, spending on it all its energy and almost completely stopping its movement. The way that a beta particle passes through a substance is called a run. It is expressed in grams per square centimeter (denoted as g / cm2).

Beta-radiation is able to penetrate into the tissues of a living organism to a depth of up to 2 centimeters. Protect against such radiation can a screen made of plexiglass of appropriate thickness.

Beta rays are one of the types of ionizing radiation. When passing through a substance, the rays lose their energy, causing ionization. The absorption of this energy by the medium can cause a number of secondary processes in the material that has been irradiated. For example, this can manifest itself in luminescence, radiation-chemical reactions, changes in the crystal structure of substances, etc. Just like other types of radiation, beta rays have a radiobiological effect.

The use of beta radiation in medicine is based on its penetrating properties in tissue. Rays are used in superficial, intracavitary and interstitial radiation therapy.