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Abstract. 2014 We have designed and built an imaging filter which can be attached to most standard TEMs, and is capable of operating at primary energies of up to 400 keV. The filter uses a 90°m agnetic sector prism, a piezoelectrically controlled energy-selecting slit, and 6 quadrupole and 5 sextupole lenses. It fully corrects second-order aberrations and distortions in images formed with electrons of selected energies, and it also produces second-order aberration-corrected spectra of variable dispersion. We show the first applications of the filter at 200 keV primary energy, which indicate that the filter will excel in chemical mapping and spectroscopy, in improving contrast of electron images and diffraction patterns, and in making high resolution electron microscopy and diffraction more quantitative. We conclude the paper with a discussion about atomic resolution image formation using inelastically scattered electrons, and the relationship between energy-filtered diffraction patterns and images formed with electrons of the same energy.

Abstract. 2014 Recent developments in instrumentation for electron energy loss spectroscopy (EELS) at Gatan R&D are reviewed. A 10-channel intrinsic Si detector with single-electron detection capability is being developed for fast energy-filtered imaging and elemental mapping in the STEM mode. A new type of an imaging filter suitable for attachment at the end of the electron-optical column of a transmission electron microscope has been designed and built. The design of the filter is described, and its electron-optical properties are compared with the properties of an optimized 03A9-filter. Finally, an unconventional design of an ultra-high resolution electron spectrometer which does not use any retardation and yet should be able to attain an energy resolution of a few meV at primary energies around 200 keV is proposed.

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