In this appendix we list a number of radionuclides which have been referred to in the text in connection with the X-radiation emitted during decay. Many decay schemes are now understood to a high degree of complexity, and we have attempted to present the data in a simplified manner, so as to stress the emitted X- and γ-radiation, and including only those γ-rays which are relatively readily observable by γ-ray and X-ray spectroscopy. The data are based for the most part on the compilation by Lederer et al. (1966).

In table A3.1 are listed 14 radionuclides which decay wholly by electron capture and which yield little or no γ-radiation. If the decay goes directly to the ground state of the daughter nuclide, the only γ-radiation emitted will be the very weak internal Bremsstrahlung associated with the electron capture decay. If the decay proceeds to an excited state, some γ-radiation will be emitted, to an extent depending upon the fraction of electron capture events proceeding to that level, and upon the degree of internal conversion. The latter process becomes important for low transition energies and high multipolarities (large changes of angular momentum during the γ-transition). When internal conversion occurs, the conversion electrons are able to produce external Bremsstrahlung in the source material.

The Q-values for the electron capture transitions are given to enable the free-recoil energy of the nucleus to be calculated (Er = Ev2/2Mc2), and to facilitate the calculation of the ratio of K: L capture (7.14).