Compton Scattering Artifacts in Electron Excited X-ray Spectra Measured with a Silicon Drift Detector
Nicholas W. Ritchie, Dale E. Newbury, Abigail P. Lindstrom
Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive x-ray spectrometry. Peaks which result from non-ideal behavior in the detector or sample can fool even an experience microanalyst into believing that they have trace amounts of an element which is not present. Many artifacts, such as the Si escape peak, absorption edges and coincidence peaks, can be traced to the detector. Others like secondary fluorescence peaks and scatter peaks can be traced to the sample. We have identified a new sample-dependent artifact which we attribute to Compton scattering of energetic x-rays from a low atomic number matrix. It seems likely that this artifact has not previously been identified because it only occurs under specific conditions and represents a relatively small signal. However with the advent of silicon drift detectors and their utility for trace element analysis we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to misidentify the Compton scatter artifact as approximately one percent of an element which is not present.