About the use of electron energy-loss spectroscopy for chemical mapping of thin foils with high spatial resolution

Core-loss energy-filtered images have been suggested as a substantial contribution to the development of an analytical electron microscope with high spatial resolution. However, for many problems in complex materials, the characteristic signals can only be detected as slope variations of the continuously decreasing background. Therefore further data processing techniques are needed to extract satisfactorily the true chemical information. A discussion of the present limits and of the existing solutions clearly shows that the method can only be developed at the expense of more elaborate systems such as simultaneous detection channels (quite well suited to the STEM instruments). Typical numbers for realistic situations illustrate the field of application of the technique.