HIGH-RESOLUTION, BROAD-BAND MICROCALORIMETERS FOR X-RAY-MICROANALYSIS

Scanning electron microscope (SEM)-based x-ray analyzers have employed wavelength-dispersive x-ray (WDX) diffractometers or energy-dispersiv e x-ray (EDX) detectors as the spectrally resolving elements. In spite of their relatively poor energy resolution (Delta E = 130 eV at 6 keV ), the solid-state EDX instruments have enjoyed much wider use than th e WDX systems (Delta E = 1-10 eV) because of their convenience and eff iciency. A microcalorimeter detector with 95% quantum efficiency at 6 keV has been developed that can produce spectra with an energy resolut ion of 7 eV over the broad energy band of 0.2-20 keV. This performance will advance the state-of-the-art for elemental analysis by virtue of its 20-fold increase in x-ray energy resolution. When coupled to an S EM it will permit the evolution of a new generation of microanalysis t ools with greatly improved spatial resolution and increased sensitivit y for minor elemental constituents. Since it will allow the SEM to ope rate at low electron energies, it will provide the ability to identify unambiguously x-ray signatures from a mixture of light and heavy elem ents. The latest performance of these detectors is presented along wit h a discussion of how they will eventually improve SEM-based microanal ysis for small particle defect review and sub-micron depth studies.