A method for forward energy-dispersive x-ray fluorescence analysis of thin and intermediate samples

The usefulness of forward geometry in Energy Dispersive X-Ray Fluorescence (EDXRF) analysis has been investigated both experimentally and theoretically. This work relates to milli- and micro-beams, which limits this work to tightly collimated incident X-ray beams (<1 mm). The use of forward geometry also limits the targets to be of thin and intermediate thickness. The advantages and the peculiarities of using a forward geometry for XRF are discussed. Forward X-Ray Fluorescence (FXRF) has features including: (a) high geometrical efficiencies when using tightly collimated primary beams; (b) a minimisation in the uncertainty in the interaction volume; (c) a sample thickness at which the production of characteristic X rays is maximised; and (d) a filtering action by intermediate thickness samples resulting in an enhancement of the sensitivity for higher atomic number elements with respect to lower atomic number elements. For thin and intermediate thickness samples simultaneous forward and backward geometry XRF can be used to correct for self-absorption effect.