About the N-series X-ray lines in the electron excited spectra of heavy elements

摘要

The electron excited N-series lines N₄N₆ and N₅N₇ of the element 74W were studied using both energy dispersive (ED) and wavelength dispersive spectrometry. In ED spectra these lines appear as one unresolved peak N_4,5N_6,7 at approximately 217 eV. The net peak height of this N-series peak relative to that of the unresolved Mα,β (M_4,5N_6,7) peak decreases rapidly with an increasing energy of the exciting electrons, E ₀. One of the reasons for this dependence is the much stronger absorption of the N-series lines. Their mass absorption coefficient (m.a.c.) in 74W was estimated to be approximately 17000 cm2 g−1. The observation of the N-series peak in the ED spectra of 70Yb and 92U leads to the assumption that, in principle, the N-series peak should be observable for all elements 70≤Z≤92. The lack of knowledge about the N-series peaks can lead to serious misidentifications. The danger of such misidentifications increases with decreasing E ₀.