Chemical sensitivity of the Kα X-ray emission of Ti and Cr compounds induced by 2 MeV protons

Kα x-ray emission induced by 2 MeV protons in thick Ti metal, TiO, Ti2O3, TiO2, MgTiO3, FeTiO3, TiC, TiN, TiB2, Cr metal, Cr2O3, CrO2, CrO3, K2Cr2O7 targets was measured using a wavelength dispersive spectrometer employing Johansson geometry to study chemical sensitivity of X-ray spectra. In the spectra the main Kα1 and Kα2 components as well as the KαL1 multiple ionization satellites were clearly resolved. The Kα1 and Kα2 peak positions and widths were extracted directly from the measured spectra in a consistent way. The results were compared with the existing data obtained by proton and photon induced ionization mechanisms, with the results of multiplet calculations, and with the observed chemical effects found in the related experimental Kβ spectra measured on the same Ti and Cr compounds at earlier times. The results obtained confirm linear correlations of the Kα1 first moments (M1) and the Kα center of gravity energy shifts with the central metal formal oxidation state, as well as between the Kα1 line widths and the Kα1 - Kβ1 M1 and/or centre of gravity energy shifts. The Kα energy shifts calculated by multiplet structure method for Cr compounds agreed with the experimentally obtained trends. Keywords: X-ray emission spectroscopy, High resolution X-ray spectra, Ti and Cr compounds, PIXE, Multiple ionization satellites.