X-ray K satellites of copper

The supra-K1 satellite spectrum of Cu was measured using a high-resolution monolithic-double-crystal spectrometer. Its total intensity relative to that of the K1 line was found to be 6×10-3, in good agreement with the only published measurement and the theoretical predictions. The spectrum includes fine structure. Relativistic Dirac-Fock (RDF) and nonrelativistic Hartree-Fock calculations were carried out and compared with the measured data in detail. The RDF calculations allow assignment of all seven structural features detected in the measured spectrum to 2p-spectator-hole transitions, with a possible small contribution from 2s-spectator-hole transitions. The new line assignments are discussed and compared to earlier work. Similar measurements were also done in the energy range between the K1 and K2 lines. Only one possible feature, on the limit of statistical significance, was found close to the energy predicted for a radiative Auger transition involving a 3d electron. Its relative intensity, 5×10-4, is much lower than predicted theoretically but within a factor of 2 from recent measurements of equivalent electron-capture-excited transitions.