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Knowledge of X-ray mass attenuation coefficients is necessary when the thick target PIXE method is applied for quantitative elemental analysis of materials. For this purpose, the X-ray mass attenuation coefficients of Veigele [Atom. Data Tables 5 (1973) 51] ave been parameterized in the photon energy range of 1–150 keV for all elements from hydrogen to plutonium ( Z = 1–94), taking into account the K-, L-, M- and N-shell absorption edge structure existing in this energy interval. This parameterization reproduces the original data of Veigele within 1%. The discrepancies existing between the Veigele data and the recent mass attenuation coefficients of Berger and Hubbell [National Bureau of Standards Internal Report NSBIR, no. 87-3597 (1987)] were compared with the experimental NBS data file [E.B. Saloman, J.H. Hubbell and J.H. Scofield, Atom. Data Nucl. Data Tables 38 (1988) 1] for the case of lead ( Z = 82). The fitted parameters were tabulated and were further used in a simple computer code generating X-ray mass attenuation coefficients for PIXE applications.

The L-X-ray production cross sections for L α1, 2 , L γ 1, 5 and L γ2, 3, 6 transitions have been measured for thin targets of nine heavy elements (Ag, Sn, Sb, Te, Ho, Ta, W, Pt and Bi) by proton and helium ion impact in the energy range 1.5 to 3.8 MeV. The ionisation cross sections for the L 1 , L 2 and L 3 subshells were extracted using fluorescence and Coster- Kronig yields of Krause and emission rates of Scofield. The influence of the uncertainties of these atomic parameters on the resulting cross sections was taken into account and discussed. The measured L-subshell ionisation cross sections were compared with results reported by other authors and with predictions of the ECPSSR theory of Brandt and Lapicki. Possible explanations for the observed discrepancies for the L 1 −, L 2 − and L-subshells are discussed.