CPB Ljubljana 2018 course book

Radioactive Decay

▪ Gamma Decay and Internal Conversion (IC)

The internal conversion process occurs mainly in nuclei with a high nuclear charge (high atomic number Z), where due to the strong electromagnetic attractive forces the atomic electrons at the inner orbits have a finite probability of staying in nucleus of that atom. In these atoms, the inner orbits are at very close distances to the nucleus. Thus an electron from such an orbit can directly take over the energy excess of the nucleus.

The energy distribution of the conversion electrons show a line spectrum , that is, as also for the case of γ-rays, characteristic for each nucleus.

In internal conversion, there will be a missing electron (hole) at the involved electron orbit. This will be then filled by another electron of a higher orbit, where characteristic X-rays or Auger electrons production will be the result.