By the law of Fajans, if an atom emits a beta particle, its electric charge increases by a positive unit and the atomic mass number does not change. This is because the mass or mass number only represents the number of protons and neutrons, which in this case the total number is not affected, since a neutron "loses" an electron, but becomes a proton, ie , a neutron becomes a proton and therefore the total number of atomic mass (protons plus neutrons) does not vary.
The interaction of beta particles with matter generally has a 10-fold greater range of action and an ionizing power equal to one tenth as compared to the interaction of alpha particles. They can be blocked completely blocked with a few millimeters of aluminum.
As far as health is concerned, beta particles are moderately penetrating in living tissue and can cause spontaneous mutations in DNA.
Beta sources can be used in radiation therapy to kill cancer cells.
This radiation takes the form of beta particles (β), which are high energy particles, ejected from an atomic nucleus in a process known as beta decay. There are two forms of beta decay, β - and β +, which respectively emit an electron or a positron.
In β + decay (observable in proton-rich nuclei), a proton interacts with an electron antineutrino to obtain a neutron and a positron (the direct disintegration of the proton in the positron has not yet been observed).
Due to the presence of the neutrino, the atom and the beta particle do not normally recoil in opposite directions. This observation seemed to violate the principle of conservation of energy and momentum, but as such did not seem likely, Wolfgang Pauli postulated the existence of a third neutral particle whose name, neutrino, was coined by the Italian Edoardo. Amaldi, a close collaborator of Enrico Fermi, who in turn developed a theory of beta decay that can still be considered valid within an optimal level of approximation. This decline is mediated by the weak nuclear force.
Uses of beta particles
Beta particles can be used to treat health problems such as cancer of the eyes and bones and are also used as markers. Strontium 90 is the most commonly used material to produce beta particles.
Beta particles are also used in quality control to test the thickness of an element, such as paper, that arrives through a roller system. Part of the beta radiation is absorbed as it passes through the product. If the product is too thick or thin, a correspondingly different amount of radiation will be absorbed. A computer program that monitors the quality of the manufactured paper will move the rollers to change the thickness of the final product.
A lighting device called betalight contains tritium and a phosphorus. When the tritium disintegrates, it emits beta particles; they hit phosphorus, causing phosphorus to emit photons, like a cathode ray tube on a television set. The illumination does not require external energy and will continue as long as tritium exists (and the phosphors do not change chemically); The amount of light produced will decrease to half of its original value in 12.32 years, the half-life of tritium.
Last review: March 8, 2019