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Sub‐surface charging, a source of error in microprobe analysis
Author(s) -
Graham J.,
Butt C. R. M.,
Vigers R. B. W.
Publication year - 1984
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.1300130308
Subject(s) - microprobe , electron microprobe , potassium , sodium , alkali metal , magnesium , analytical chemistry (journal) , chemistry , mineralogy , materials science , metallurgy , chromatography , organic chemistry
Qualitative microprobe analysis of sodian potassian hydroxonian meta‐autunite failed to reveal any sodium, although nearly 3% was present. Potassium, magnesium and calcium were underestimated to a smaller extent in related natural and synthetic structures. The effect is due to the migration of these interlayer cations from the analysed region—almost instantaneously in the case of sodium—and a consequent decrease in count rates, under the influence of the space‐charge resulting from the incident electron beam. Experiments with the autunites and with a soda‐glass subjected to various coating treatments showed that the effect of charging can be dramatic. Such charging also occurs when alkali metals are not present, a fact which has important implications for all microprobe analyses.