The energetic spectrum of alpha decay is composed of lines. That is why, during alpha decay, the emission of monoenergetic alpha particles is accompanied by the emission of γ radiation quantum. Then the nuclei almost immediately transitions into the ground state, via the emission of an electromagnetic γ radiation quantum. After the emission of an alpha particle, the daughter nucleus is in an excited state. The kinetic energy of the emitted alpha particle usually does not equal the decay-energy (Q), but is somewhat lower. Due to the low weight, the nuclear kinetic energy during the emission of alpha particle is practically negligible. The emitted particle has a low weight compared to the weight of the emitting nucleus. In the periodic table this nucleus is located 2 places to the left from the original paternal nucleus. When emitting an alpha particle, the paternal nucleus undergoes radioactive transformation as described bellow:įollowing this transformation, a daughter nucleus is formed. Alpha particle has two positive elementary charges due to the presence of two protons. As these 4 nucleons possess quite a high binding energy, the group behaves like one single particle. The repulsive forces increase with the increasing proton number.Īlpha particle is composed of two protons and two neutrons. This decay occurs only in heavy natural radionuclides, and can be explained by the mutual repulsive forces between protons. Nuclear transformation serves the purpose of reaching a more stable energetic state.Īlpha decay is the longest known and the most often observed case of a spontaneous emission of a heavy particle from an atomic nucleus. The total energy remains the same when transforming a nucleus according to the scheme X → X´ + particle + hυ. The sum of the momentum of the daughter nucleus and the momentum of the emitted particles equals zero when transforming a nucleus according to the scheme X → X´ + emitted particle. The number of parental nucleus‘ nucleons before transmutation will equal the sum of the daughter nucleus‘ nucleons + the emitted nucleons.
For example, if the nucleus emits one electron carrying negative elementary charge, the nucleus gains one positive elementary charge.
The electric charge is the algebraic sum of the charge of the nucleus, and the charge of the emitted particles remains constant. The dimensions referred to are the electric charge, the number of nucleons, the momentum, and the energy. In all cases of transformation, the physical dimensions remains preserved. In some cases, electromagnetic radiation γ quantum (pure γ emitters are usually nuclear isomers) is emitted. The transformation of radioactive nuclei is accompanied by an emission of a particle. Previous chapter: 5.2.2 Quantities and Units
0 kommentar(er)
