Alpha decay

Alpha decay is radioactive decay in which an unstable nucleus emits a helium-4 nucleus, lowering its proton number by two and mass number by four.

Alpha particle: An alpha particle is a helium-4 nucleus containing two protons and two neutrons. It is the particle emitted when an unstable nucleus undergoes alpha decay.
Atomic nucleus: An atomic nucleus is the dense, positively charged center of an atom, composed of protons and neutrons. Alpha decay is a transformation of the nucleus rather than the surrounding electrons.
Alpha spectroscopy: Alpha spectroscopy measures the energies and intensities of alpha particles emitted by radioactive materials. Discrete alpha energies help identify decaying isotopes and their daughter nuclei.
Beta decay: Beta decay is radioactive decay in which a nucleus emits an electron or positron through a weak-interaction transformation. Unlike alpha decay, it changes proton number by one without ejecting a four-nucleon cluster.
Quantum tunneling: Quantum tunneling is the passage of a particle through an energy barrier it could not cross classically. Alpha particles escape the nuclear barrier by tunneling through it.
Proton number: Proton number is the number of protons in an atomic nucleus and determines the element’s identity. Emitting two protons changes the parent atom into a different element.
Alpha decay chain: An alpha decay chain is a sequence of radioactive transformations connected by successive nuclear decays. Heavy nuclides often reach stable products through repeated alpha emissions and other decays.
Gamma decay: Gamma decay is the emission of a high-energy photon as an excited nucleus loses energy. It changes nuclear energy but does not reduce proton number or mass number.
Nuclear potential: A nuclear potential describes the forces and energy experienced by particles inside and around an atomic nucleus. Its attractive interior and repulsive exterior create the barrier an alpha particle must escape.
Mass number: Mass number is the total number of protons and neutrons in a particular nucleus. The emitted helium-4 nucleus lowers the parent’s mass number by four.

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