In this work, fluorescence yields and Coster–Kronig transition probabilities of the tantalum L-shell are determined with a reliable uncertainty budget.

Fluorescence yields and Coster–Kronig factors of the ruthenium L-shell are determined experimentally for the first time with reliable uncertainty budgets.

Using radiometrically calibrated instrumentation of Physikalisch-Technische Bundesanstalt, the L-shell fluorescence yields and Coster-Kronig factors of tantalum (including the uncertainty budget) were experimentally determined based on transmission and X-ray fluorescence experiments. The determined fluorescence yields (ω L3 = 0.247(12), ω L2 = 0.278(15), ω L1 = 0.157( 12)) were independently validated trough XRR-GIXRF experiments. Both, the Coster-Kronig factors (f 23 = 0.123(84), f 13 = 0.328(152), f 12 = 0.14( 11)) as well as the fluorescence yields are in good agreement with the most established databases in the field of X-ray fluorescence.