Parallel Data Collection Wavelength Dispersive X-ray Spectrometer for Scanning Electron Microscopy

This project will develop a new type of Wavelength Dispersive Spectrometer (WDS) for use on Scanning Electron Microscopes. Instead of the slow serial scan used in a conventional WDS, the new system will collect and display data in a parallel fashion, thereby enabling the user to make very fast decisions about his/her samples. The device will be a variation on the Von Hamos style x-ray spectrometer that uses (1) diffractors with a small radius of curvature and (2) new long charge couple detectors (CCDs) arranged to simultaneously collect data from a very wide spectral range. In Phase I, the parallel data collection technique was demonstrated on a proof-of-concept system over a very narrow (300 eV) spectral interval. Tests were conducted to demonstrate a higher resolution at this energy than for any commercially available spectrometer. A design for a Phase II spectrometer was determined and software was written to allow a user to limit noise levels. Phase II will involve the construction of a spectrometer that provides parallel data collection over the energy range from 2100 eV to 10,000 eV. This system will be extensively tested on an SEM and on a small spot x-ray fluorescence (XRF) system. The system also will be tested for its ability to produce spectral images of spots as large as 1 mm with 0.05 mm resolution.Commercial Applications and other Benefits as described by the awardee: The new system could be combined with an existing spectrometer to produce an expanded system that covers the entire energy range from 100 eV to 10,0000 eV for use on SEMs. In addition, the system could be used on stand-alone XRF systems for the analysis of small features, such as grains of rock, electronic circuits, and fibers.