Theoretical and experimental determination of $K$- and $L$-shell x-ray relaxation parameters in Ni

Fluorescence yields (FY) for the Ni $K$ and $L$ shells were determined by a theoretical and an experimental group within the framework of the International Initiative on X-ray Fundamental Parameters (FPs) collaboration. Coster-Kronig (CK) parameters were also measured for the $L$ shell of Ni. Theoretical calculations of the same parameters were performed using the Dirac-Fock method, including relativistic and QED corrections. The experimental values for the FY and CK were determined at the PTB laboratory in the synchrotron radiation facility BESSY II, Berlin, Germany, and are compared to the corresponding calculated values.

Figure 1

X-ray emission spectrum of the 500 nm free-standing nickel foil. The energy of the exciting radiation was 1030 eV which is above the $L_1$-absorption edge. The fitted model spectrum is plotted in green, the fluorescence lines in blue and satellite lines in red.

Figure 2

The partial photoelectric cross sections (PECS) derived from the transmission measurements of the thin Ni foil. Only relative cross sections were determined, the thickness $d$ of the sample is not needed to calculate the fluorescence yields and Coster-Kronig factors.

Figure 3

Derived partial fluorescence yields for each subshell. The final values (dashed lines) are averages performed in the regions that are color marked (blue for ${\omega }_{L_3}$ and red for ${\omega }_{L_2}$ and ${\omega }_{L_1}$).