Compton-scattered tungsten X-rays as a measure of mass absorption coefficients in rocks

The intensity of Compton-scattered WLα_c X-rays may be used to estimate mass absorption coefficients (μ) analogous to Reynolds’ (1963) method for MoKα_c radiation. This procedure depends on removal of two interfering sources of radiation: (1) Rayleigh-scattered WLα X-rays at 1.476 Å may be eliminated by use of a Ni filter (absorption edge = 1.488 Å). (2) Fluorescent Nikβ radiation generated in any Ni-bearing rock occurs at the same wavelength (1.500 Å) as the WLα_c peak. The constant relative intensity of Nikα and NiKβ permits determination of an empirical correction factor (independent of sample Ni content) for this interference. Application of these procedures with a linear calibration curve (μ vs WLα_c intensity) generally yields a μ. within 5 percent of that calculated from chemical composition.