SE EEDF N0(Ek) for argon ions on metallic titanium (Ti) and titanium oxide (TiOx) at argon ion energies of 500 eV (a), 800 eV (b), 1000 eV (c), and 2000
eV (d). The symbols present the SE EEDFs from the beam experiment. The lines connecting the data points serve as a guide for the eye. The solid lines show the SEEEDF of the extended Hagstrum model using Pt,33 = 0.02 and Pt,58 = 0.1, for details see text. The green solid line denotes the EEDF N0 of the secondary electrons outside the solid and the blue solid line its convolution with a Gaussian width of 8 eV, for details see text. The black solid line denotes the EEDF Ni(Ek) of the electrons inside the solid.

SE EEDF measurements with ECR source.