“…The pursuit of high detection efficiencies through the development of parallel-detection electron energy loss spectrometers, which was initiated by Egerton [2], Johnson [3], and others, and developed into an efficient instrument by Shuman [4], has resulted in a commercially available spectrometer [5,6], which is now permitting new levels of performance to be attained in many laboratories. Energy-filtered imaging, which was originally developed by Castaing and Henry [7], has also lead to a commercially available instrument, and is now being used for imaging with improved contrast as well as for chemical mapping of major constituents [8]. There is also much interest in improving the attainable energy resolution, both by optimizing the performance of spectrometers attached to microscopes using cold field emission guns with a narrow energy spread [9][10][11], and by decreasing the energy spread of the gun further through the use of a monochromator [12,13].…”