We report on the use of a microcalorimeter X-ray detector with a transition edge sensor in an electron probe to perform quantitative analysis. We analyzed two bulk samples of multielement glasses that have been previously characterized by chemical methods for use as standard reference materials. The spectra were analyzed against standards using three different correction schemes. In one of the standards, the reference line was easily resolved despite its proximity within 45 eV of another line. With the exception of direct measurements of oxygen (a particularly challenging element), the results are in agreement with the certified characterization to better than 1% absolute or 8% relative. This demonstrates the potential of microcalorimeter detectors as replacements for conventional energy dispersive detectors in applications requiring high energy resolution.

Two recent developments in X-ray spectrometer technology provide dramatic improvements in analytical capabilities that impact the frontiers of electron microscopy. Silicon drift detectors (SDD) use the same physics as silicon (lithium) energy dispersive spectrometers [Si(Li) EDS] but differ in design: only 10% of the thickness of the Si(Li) EDS with an anode area below 0.1 mm2 and a complex rear surface electrode pattern that creates a lateral internal charge collection field. The SDD equals or betters the Si(Li) EDS in most measures of performance. For output versus input count rate, the SDD exceeds the Si(Li) EDS by a factor of 5 to 10 for the same resolution. This high throughput can benefit analytical measurements that are count limited, such as X-ray mapping and trace measurements. The microcalorimeter EDS determines the X-ray energy by measuring the temperature rise in a metal absorber. Operating at 100 mK, the microcalorimeter EDS achieves resolution of 2–5 eV over a photon energy range of 200 eV to 10 keV in energy dispersive operation, eliminating most peak interference situations and providing high peak-to-background to detect low fluorescence yield peaks. Chemical bonding effects on low energy (<2 keV) peak shapes can be measured.