CPB Ljubljana 2018 course book

daughter *

Radioactive Decay

γ-rays

daughter

▪ Gamma Decay and Internal Conversion (IC)

For all the decay schemes, the daughter nucleus is in most of the cases in an excited energetic state. Its energy excess is usually emitted as γ-rays: these are photons, having their origin in nucleus and showing a line energy spectrum (photons emitted at discrete energies) . This process of emitting γ-rays is called gamma decay . In addition to the γ-ray emission, there is another mechanism by which the daughter nucleus can loss its energy excess. This is by transferring its energy excess directly to an inner orbital electron, which then escapes the atom with a kinetic energy equal to the difference of the nucleus excess energy and the binding energy of the involved electron. This process is called internal conversion (IC) and the involved electron is called internal conversion electron or simply conversion electron (CE) . In both gamma decay and internal conversion process, the atomic number Z, the mass number A as well as the number of neutrons N in the nucleus remain unchanged ( isomeric transition ).