1 Answers
Delayed nuclear radiation is a form of nuclear decay. When an isotope decays into a very short-lived isotope and then decays again to a relatively long-lived isotope, the products of the second decay are delayed. The short-lived isotope is usually a meta-stable nuclear isomer.
For example, gallium-73 decays via beta decay into germanium-73m2, which is short-lived. The germanium isotope emits two weak gamma rays and a conversion electron.
Because the middle isotope is so short-lived, the gamma rays are considered part of the gallium decay. Therefore, the above equations are combined.
However, since there is a short time delay between the beta decay and the high energy gamma emissions and the third and fourth gamma rays, it is said that the lower energy gamma rays are delayed.