ChemiSTEM Technology Provides Higher X-Ray Count Rate
Information on the chemical composition of materials on the nanoscale is pivotal for an understanding of nanostructures and devices, and X-ray spectrometry is a well-established, robust and easy to use technique to obtain this information. Better yet, in the Scanning/Transmission Electron Microscope (S/TEM), X-ray analysis pairs microstructural information obtained from high-resolution imaging with accurate chemical composition information. But there has been an historical limitation with X-ray systems for the S/TEM: they collect only about 1% of all X-rays generated by the electron beam passing through the very thin sample. Recently, as the desired spatial resolution of chemical analysis has become progressively greater, the X-ray signal has decreased because of fewer atoms excited in smaller analytical volumes (a consequence of smaller electron beams and thinner samples). This results in low signal strength, bringing about low sensitivity and hence long analysis times – until now.
ChemiSTEM technology overcomes the limitations of conventional energy dispersive X-ray (EDX) analysis to deliver enhanced performance improvements:
Speed- Increases in X-ray count rates of 50x or more translate directly into faster maps and analyses. Maps that took hours to acquire now take only minutes.
Sensitivity- Higher X-ray count rate can be used to enable detection of low elemental concentrations. The technology has detected elemental concentrations as low as a few hundredths of a percentage weight in specific applications
Light Elements– FEI’s proprietary windowless detector design has proven to be not only beneficial for enhancing light element detection sensitivity, but also in the detection sensitivity of all elements
ChemiSTEM Technology combines technical advances in beam generation with disruptive changes in EDX signal detection. The system comprises proprietary X-FEG high-brightness electron source, proprietary patent pending Super-X detector system consisting of 4 windowless SDD detectors integrated close to the saltmple area, and fast electronics capable of EDX spectral rates of up to 100,000 spectra/sec.