ALCHEMI: a new technique for locating atoms in small crystals

John Spence, J. Taftø

Research output: Contribution to journalArticlepeer-review

270 Scopus citations


Atom Location by Channelling Enhanced Microanalysis (ALCHEMI) is a quantitative technique for identifying the crystallographic sites, distribution and types of substitutional impurities in many crystals. The method involves no adjustable parameters, can be applied to areas as small as a few hundred Angstroms and to impurity concentrations down to about 0·1 atomic per cent. It is capable of distinguishing neighbours in the periodic table. The method uses the incident electron beam orientation dependence of characteristic X‐ray emission and uses an energy dispersive X‐ray microanalyser fitted to a transmission electron microscope. The method does not require the specimen thickness or precise orientation to be known, and makes few assumptions about the form of the dynamical electron wavefunction, which need not be calculated or predicted. The classical problems of cation ordering in spinels, feldspars and olivine have now been studied by this method. 1983 Blackwell Science Ltd

Original languageEnglish (US)
Pages (from-to)147-154
Number of pages8
JournalJournal of Microscopy
Issue number2
StatePublished - May 1983


  • X‐ray absorption
  • atom location by channelling enhanced microanalysis
  • enhanced X‐ray emission

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology


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