Radioactive Decay

The spontaneous change of an atomic nucleus accompanied by the emission of alpha, beta particles or gamma radiation.

Alpha Decay

Nuclear decay by emission of an alpha particle (⁴He nucleus).

Beta Decay

Nuclear decay by emission of an electron or a positron. Positron decay is always accompanied by electron capture decay.

Gamma Rays

Gamma ray emission is a decay mode by which the excited state of a nucleus de-excite to lower (more stable) state in the same nucleus.

See also: Activity, Alpha Particle, Beta Particle, Gamma Rays, Scintillation Counter.