Non-Sequential Spectral Acquisitions and Data Reconstruction to Remove Time-Dependent Effects from X-Ray Spectra.

Abstract

X-ray spectroscopy techniques may require prolonged exposure of a sample to an electron beam to generate X-rays. With typical spectroscopic methods the measured signal is acquired while varying the independent parameter in a systematic way, for example, stepping a photon detector in a series of energy steps from one end of the range of interest to the other incrementally or varying the energy of the incoming excitation incrementally. This can be a time-consuming process when signal strength is low, and if the sample is affected by prolonged beam exposure it could potentially change the shape and position of the obtained X-ray spectrum. Hydrocarbon contamination is of particular concern in electron beam instruments because of the interaction between the hydrocarbons and the electron beam at the point of impact on the sample surface. The authors suggest that hydrocarbon contamination does affect the generated spectra and present methods for removing this (and other) time-dependent artifacts for low-voltage X-rays. The software is freely available as a compiled Windows executable and as source code (http://geoscience.wisc.edu/geoscience/?p=16417).