What is alpha decay?

Today we will talk about what is alpha decay and how it can be explained in terms of classical and alternative theories. The existence of the material world is possible only because the structures of which any substance consists are sufficiently stable. The forces connecting the particles in atoms together are the basis for the existence of the entire universe. Modern models of the atomic device allow not only to formulate laws, but also to explain many observed phenomena of the microworld. Within the planetary model in the center of each atom is a nucleus, which includes protons and neutrons in equal parts. The ratio of protons, neutrons and electrons is represented as 1: 1: 1. This only at first sight seems incredible, in fact, this dependence is a consequence of one of the key laws of the universe: the electric charge of the electron is -1, the proton is +1, and the neutrons, as a union of the two smaller, oppositely charged elements, are generally electrically neutral , Hence the name).

Thanks to the Coulomb forces, the protons in the nucleus repel each other, but the counterbalancing strong interaction keeps the particles together. What is alpha decay? The mechanism of its occurrence is very simple: if the protons are separated from each other, the force of the electro-repulsion becomes greater than the strong interaction, which leads to the formation of a lighter core and particle. The reasons for the initial distance are varied - these can be both external influences and structural features of the nucleus (entropy factor).

The collapse of the worldview

Until 1896 it was believed that the atoms are indivisible, and the structure of each is characteristic of a certain substance. But A. Becquerel (sometimes indicated by Rutherford), who studied uranium salts, discovered the phenomenon of radioactivity, which cast doubt on many of the postulates of the atomic theory of the time. Alpha decay is the emission of positively charged particles - helium-4 nuclei. It is noted that this process is characteristic primarily for nuclei of heavy elements. One of the features of the alpha particle is its double positive charge. This is explained by the fact that there are no two electrons in the structure. The total charge is then +2. Alpha decay was studied by Rutherford. He determined that such a particle structure (2 neutrons + 2 protons) is extremely stable and, theoretically, most other nuclei would have to decay into similar particles and nuclei of lighter elements. However, this does not happen. Rutherford suggested that any nuclear change is possible only if a helium atom (alpha particle) or a high-energy electron (beta particle) comes into it. Subsequently, this was confirmed, but it took tens of years of research and the introduction of a new concept from the field of quantum mechanics - the tunnel transition.

Overcoming the barrier

As mentioned above, a stable structure is an alpha particle. Its charge is from 2 to 10 MeV. In order for it to penetrate the basis of the atom, it is necessary to overcome the forces of electric repulsion (after all, the protons are present in the core and particle). This is the very barrier, after which the forces of intranuclear attraction begin to predominate. The laws of the microworld differ from those we are accustomed to, so in some cases, in order to pass through the wall, it is not necessary to destroy it. Through a tunnel junction, it is possible to overcome the barrier. The smaller the difference between the energy of the particle and the cost of passage, the higher the probability of overcoming repulsion. For most nuclei, the possibility of tunneling is so small that they can be considered as stable formations. Others, under certain conditions, allow the penetration from the outside (and outflow from within) of alpha particles.