Computer-aided parallel EELS techniques: acquisition, processing, & imaging

Abstract

The recent commercial introduction of the parallel detection electron energy-loss spectrometer has undoubtedly made electron energy-loss spectroscopy (EELS) more viable as a technique for routine microanalysis. Additionally, the increased recording efficiency of parallel EELS (PEELS) warrants the use of more involved acquisition and processing techniques than was necessary, or even possible with serial EELS. This increased complexity places greater demands on the computer systems controlling data acquisition. Multichannel analyzers systems with small resources and limited programming facilities are not capable of exploiting the full capabilities of the PEELS spectrometer.Preliminary efforts of the author with the Gatan PEELS spectrometer were concentrated on development of a flexible acquisition system at National Institutes of Health. Hardware control is performed through machine-language drivers called from high-level languages (HLL) such as FORTRAN and C. The software drivers and hardware were designed to minimize processor involvement in the data collection process, resulting in the capability to collect data while processing continues within the parent HLL. This design simplifies the HLL program structure and minimizes data collection dead time.