Minerals and Metals in Ancient India v1.c29.s1.6

v1.c29.s1.6

We have also demonstrated (Biswas, 1989: 20-21) that selective area electron diffraction (SAED) pattern analysis in transmission electron microscopy (TEM) reveals the X-ray amorphous phases and explained how simultaneous EDAX studies with secondary as well as back-scattered electrons permitted us to quantitatively determine as many as 14 elements in a narrow zone of 0.1 µm. These techniques have tremendous possibilities in the analysis of archaeological samples. The family of photo-electron spectroscopy (PES) techniques such as ESCA or electron spectroscopy for chemical analysis involves the short escape depth of the excited electrons, and therefore can provide special information about a very thin surface layer (such as in gilded icons) as contraposed to the information of the bulk. Electron energy loss spectroscopy or EELS is ideally suited for the study of low atomic number elements in artefacts and archaeological residues.