Dependence of XRF intensity on the tilt of the propagation plane: Experimental

The geometrical properties of the x‐ray fluorescence (XRF) intensity related to the α‐parameterization were confirmed experimentally. A special sample stage was built to allow the rotation of the sample with the propagation plane (the plane defined by the incident and take‐off beam directions) and was coupled to an energy‐dispersive spectrometer. The device and the way in which it was carefully aligned with the collimated x‐ray beams are described. The fluorescence spectra of three NBS standard samples were measured for 16 different positions of the α angle. The incident and take‐off angles were both 45° for sample rotations between α = 0 and the maximum angle of 86°. XRF intensities from non‐enhanced lines do not show any dependence on α as predicted by theory. Enhanced lines, on the contrary, decrease in intensity when α increases, allowing the isolation of the primary emission by extrapolation to the limiting case α = π/2. Copyright © 1991 John Wiley & Sons Ltd.