The most common types of radioactive decay that do not cause transmutation are gamma decay and the related process internal conversion.

The internal conversion process competes with gamma decay.

These usually immediately undergo gamma decay but a small fraction of them are excited enough to be able to decay by emitting a neutron in addition.

An example is internal conversion, which results in electron and sometimes high-energy photon emission, even though it involves neither beta nor gamma decay.

The first gamma ray source to be discovered historically was the radioactive decay process called gamma decay.

A gamma decay was then understood to usually emit a single gamma photon.

Isomeric transition is the name given to a gamma decay from such a state.

A few gamma rays in astronomy are known to arise from gamma decay (see discussion of SN1987A) but most do not.

It has been reported experimentally by direct observation that the half-life of Ta to gamma decay must be more than 10 years.

It decays to the ground state via gamma decay with a half-life of 6 hours.