Investigation of filter applicability at XRF analysis in the longwave range

Abstract

The theoretical and experimental results of evaluating the X-ray intensity variation of the analytical lines and X-ray bremsstrahlung radiation, scattered by the sample atoms with wavelengths in the 0.1-0.7 nm range, with the optimal thickness of the A1-filter are presented. The experiment was performed using WDXRF spectrometer S8 TIGER (Rh anode, Be-window 75 μm thick, LiF 200). The obtained data for the Al-filter with thickness more than 100 μm have shown that the background associated with scattering of the primary X-ray radiation by the sample in the first reflection order does not contribute to the background intensity for the Cs L α 1 line. However, the intensity of the scattered radiation in the second reflection order by Al-filters decreased less and, therefore, its contribution became predominant. The influence of the X-ray tube potential on the contribution to the background intensity of the primary X-ray bremsstrahlung radiation scattered by the analyzing crystal in the second order of reflection was studied. The experiment for Al-filter with 12.5 μm thickness has shown that the contrast of the Cs L α 1 line radiation increased by a factor of 1.5 in comparison with experiments without the filter. It was also shown that thicker filters lead to a significant decrease in the Cs L α 1 line intensity. However, the contrast of Ba L α 1 , La L α 1 , Ce L β 1 and Nd L α 1 lines radiation is not sensitive to the filter usage. Keywords : X-ray fluorescence analysis, filtration of the primary radiation DOI: http://dx.doi.org/10.15826/analitika.2018.22.2.009 (Russian) A.G. Revenko, D.S. Suvorova, E.V. Khudonogova Institute of the Earth’s Crust, SB RAS, 128 Lermontov St., Irkutsk, Russian Federation