An accuracy assessment of photo-ionization cross-section datasets for 1-2 keV x-rays in light elements using PIXE

作者：Heirwegh C M^*; Pradler I; Campbell J L

来源：Journal of Physics B: Atomic, Molecular and Optical Physics , 2013, 46(18): 185602.

DOI：10.1088/0953-4075/46/18/185602

Proton-induced x-ray emission (PIXE) was used to assess the accuracy of the National Institute of Standards and Technology XCOM and FFAST photo-ionization cross-section databases in the low energy region (1-2 keV) for light elements. Characteristic x-ray yields generated in thick samples of Mg, Al and Si in elemental and oxide form, were compared to fundamental parameters computations of the expected x-ray yields; the database for this computation included XCOM attenuation coefficients. The resultant PIXE instrumental efficiency constant was found to differ by 4-6% between each element and its oxide. This discrepancy was traced to use of the XCOM Hartree-Slater photo-electric cross-sections. Substitution of the FFAST Hartree-Slater cross-sections reduced the effect. This suggests that for 1-2 keV x-rays in light element absorbers, the FFAST predictions of the photo-electric cross-sections are more accurate than the XCOM values.

• 出版日期2013-9-28