Lowering the limit of detection in high spatial resolution electron beam microanalysis with the microcalorimeter energy dispersive X-ray spectrometer

Low-beam-energy X-ray microanalysis with the field-emission-gun scanning el ectron microscope suffers limitations due to physical factors of X-ray gene ration. Instrumental limitations are imposed by the poor resolution of the conventional semiconductor energy dispersive X-ray spectrometry. Wavelength dispersive X-ray spectrometry provides sufficient resolution to solve spec troscopic problems, but the poor geometric efficiency and the single channe l nature of spectrum measurement restrict its practical use for low-beam-en ergy microanalysis. The microcalorimeter energy dispersive X-ray spectromet er combines high resolution ( < 10 eV) with energy dispersive operation. Th e utility of this new spectrometer is examined in four categories: (1) qual itative analysis; (2) quantitative analysis; (3) chemical speciation studie s, and (4) measurement of trace constituents. For the low-beam-energy regim e, the microcalorimeter energy dispersive X-ray spectrometer provides impor tant new performance capabilities for qualitative analysis and chemical spe ciation studies. However, there are limitations for quantitative studies im posed by detector geometrical characteristics. In addition, trace element d etection is impractical below 0.001 mass fraction with low-beam energy ( < 5 keV) because of count rate limitations. Published by Elsevier Science B.V .