Gamma Decay
A radioactive decay process where an excited atomic nucleus transitions to a lower energy state by emitting a high-energy gamma-ray photon.
Governing formula
ᴬ_Z X* → ᴬ_Z X + γ (High-energy photon emission)
SI unit
MeV or keV (Photon Energy)
In depth
Gamma decay alters neither atomic number Z nor mass number A. It frequently follows alpha or beta decay when daughter nuclei are left in excited nuclear energy levels, de-exciting via electromagnetic photon emission.
Examples in the real world
Technetium-99m de-exciting to Technetium-99 by emitting a 140 keV diagnostic gamma-ray photon.