Alpha decay

Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or 'decays' into an atom with a mass number that is reduced by four and an atomic number that is reduced by two. An alpha particle is identical to the nucleus of a helium atom, which consists of two protons and two neutrons.

Mechanism of Alpha Decay

The mechanism of alpha decay can be explained using quantum mechanics. In quantum mechanics, alpha particles are described as a tunneling through a potential barrier. This is known as quantum tunneling. In classical mechanics, particles can only overcome potential barriers if they have enough energy, but in quantum mechanics, particles can tunnel through potential barriers even if they do not have enough energy.

Energy Release in Alpha Decay

The energy released in alpha decay is substantial. This energy comes from the mass difference between the parent atom and the products of decay. According to Einstein's equation E=mc^2, mass can be converted into energy, and this is what happens in alpha decay. The energy is carried away by the alpha particle and the recoil of the daughter nucleus.

Applications of Alpha Decay

Alpha decay has several applications. It is used in smoke detectors, where a small amount of americium-241, which decays by alpha emission, is used to ionize air and detect smoke particles. Alpha decay is also used in radioactive dating, specifically in dating rocks and minerals.

Health Effects of Alpha Decay

Alpha particles emitted by alpha decay are not very penetrating and can be stopped by a sheet of paper or the outer layer of human skin. However, if alpha-emitting substances are ingested or inhaled, they can be harmful, as alpha radiation is highly ionizing and can damage living cells.

See Also

• Beta decay
• Gamma decay
• Radioactive decay
• Quantum mechanics
• Quantum tunneling