AlphaEmission
Alpha emission, also known as alpha decay, is a form of radioactive decay in which an unstable atomic nucleus releases an alpha particle, a helium-4 nucleus consisting of two protons and two neutrons. This process reduces the parent nucleus by four mass units and by two atomic numbers, producing a lighter daughter nuclide. For example, uranium-238 decays to thorium-234 via alpha emission: 238U → 234Th + 4He.
Mechanism and energetics: The alpha particle is pre-formed in the nucleus and must overcome the Coulomb barrier
Penetration and safety: Alpha particles have high ionizing power but very short range in matter, being stopped
Applications and significance: Alpha decay explains the transmutation of heavy elements and contributes to radiometric dating