Specimen surface and thickness effects on EDS mapping

Gatan instrument used

EDAX^® Octane Elect Plus EDS analysis system with APEX™ software and PECS™ II broad beam ion mill

Background

Determination of compositional variations in a sample can quickly and efficiently be done using energy dispersive x-ray spectroscopy (EDS) mapping. This can yield region of interest (ROI) intensity, background corrected, and fully quantitative maps. On bulk samples with a flat surface, the spectral processing can correct for variations in EDS signal due to compositional changes to produce images that can be directly interpreted. However, when the specimen surface is rough, or if a sample is electron transparent and not of equal thickness, differences in x-ray generation and detection may shield the true compositional microstructure. During EDS mapping with the APEX software, a counts per second (CPS) map is automatically collected to assist with correcting these artifacts.