Type of radioactivity in the most common form of which an unstable atomic nucleus dissipates energy by gamma emission, producing gamma rays .
Gamma decay also includes two other processes, internal conversion and internal pair production . In internal conversion, excess energy in a nucleus is transferred to one of its own orbiting electrons and the electron is ejected from the atom . In internal pair production, excess energy is converted into an electron and a positron , which are emitted together. Typical half-lives (see half-life ) for gamma emission range from about 10 -9 to 10 -14 second.