Все науки. №6, 2022. Международный научный журнал

Such nuclear reactions are exo-energetic or energy-releasing. The first nuclear reaction was carried out by Ernest Rutherford in 1917, when alpha particles bombarded the nuclei of nitrogen atoms. It was completely fixed due to the appearance of secondary ionizing particles, whose mileage in the gas was greater than the mileage of alpha particles, after which they were identified as protons. The process was later photographed.

By the way, about this, it is important to say that a Wilson camera is used to photograph nuclear reactions.

Speaking about the mechanisms of interaction, we can distinguish two types of such interaction, namely:

1. Reaction with the formation of a composite nucleus, this process consists of two stages, while the incoming particle combines with the bombarded nucleus itself, forming a common core, which later decays. Such a nuclear reaction proceeds at low energies, up to 10 MeV;

2. Direct nuclear reactions that take place immediately, in nuclear time, which is the smallest fractions of a second and are calculated based on other factors, one of which is the time of crossing the nucleus by a particle.

Basically, this type of reaction is expressed only at very high energies of the bombarding particles.

If the original nuclei are preserved after the nuclear reaction itself, no new particles are also born, then the reaction is considered elastic scattering in the field of nuclear forces, without any internal interaction.

Such a reaction is accompanied only by the transfer of kinetic energy and momentum of one incoming particle to the target nucleus, being called potential scattering and fully obeying the laws of conservation of momentum in this case.

The reaction mechanisms were mentioned earlier, but it is worth dwelling on them in more detail. The first reaction, namely the mechanism of the composite nucleus, was first developed and proposed by Niels Bohr in 1936 together with the famous theory of the droplet model.

This theory even today underlies the great ideas about all nuclear reactions.

If we follow this theory, then, as described, the nuclear reaction follows in two stages, while the entire process from collision, formation of a composite nucleus and its decay takes within 10-23-10-21 seconds.