The first observation of all the basic components of the KLL Auger spectrum of Sm generated in the radioactive decay of 147,148,149Eu atoms in a solid state source

The KLL Auger spectrum of Sm ( Z = 62) following the electron capture decay of radioactive 147,148,149 Eu atoms in a solid state source was measured with the instrumental resolution of 14 eV. Energies and relative intensities of all the nine basic spectrum components were determined and compared with those of the previous measurement and theoretical predictions. Our absolute Auger transition energy 32627.3 ± 1.4 eV for the dominant KL 2 L 3 ( 1 D 2 ) transition was found to be higher by 16.0 ± 1.4 eV than that one of the widely used relativistic semi-empirical calculations by Larkins. Taking into account results of our measurements of the L 3 M 4 M 5 ( 1 G 4 ), L 3 M 5 M 5 ( 3 F 4 ), and KL 2 L 3 ( 1 D 2 ) Auger lines from both the EC decay and the β − decay for atomic numbers Z = 62 and 64 and also previous experimental data a conclusion is made that the discrepancy found is caused by the “atomic structure effect”. The measured value for the KL 1 L 2 ( 3 P 0 / 1 P 1 ) transition intensity ratio proved strong influence of the relativistic effects on the intensity distribution between the 3 P 0 and 1 P 1 doublet components.