Intrinsic and effective sensitivities of analysis by X-ray fluorescence induced by protons, electrons, and photons

Abstract

The intrinsic analytic sensitivity to trace elements of X-ray fluorescence induced by protons, electrons and photons, defined in terms of an irreducible background and a “perfect” detector, is much lower than that observed with present source strengths. As ion flux densities increase and spatial resolutions improved, the sensitivity is likely to be limited by sample heating and by the Frenkel pair radiation damage. At a proton fluence density of ∼10 20/cm 2, the displacement damage is complete; the sample is amorphous. If the fluence density is limited to this value, then, at 1 μm resolution, the ultimate sensitivity of proton induced X-ray analysis will be about one atom of the trace element per million atoms of the host.