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Influence of some practical factors on background extrapolation in EELS quantification
Author(s) -
Liu DR.,
Brown L. M.
Publication year - 1987
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1987.tb02816.x
Subject(s) - extrapolation , minor (academic) , element (criminal law) , noise (video) , residual , statistics , limit (mathematics) , curve fitting , algorithm , mathematics , physics , computer science , mathematical analysis , law , artificial intelligence , political science , image (mathematics)
SUMMARY The detectability of a minor element with EELS in a STEM is of great interest. This paper first describes errors resulting from a conventional background extrapolation scheme and other faults in the collected spectra which in effect greatly reduce the seemingly good signal to noise ratio of a spectrum and therefore impose much more stringent statistical counting requirement on spectra if a small amount of element is to be quantified with good accuracy. Secondly, the systematic variation of the index r of the power law background fitting curve of an ionizatoin edge tail is discussed. Its effect on the detectability of a minor element is analysed. It puts a lower limit on the detectability of an element, however many counts are accumulated. Also a scheme is proposed of some non‐conventional linear least squares fits by which one might suffer from less quantification error due to background extrapolation and achieve lower detectability of a minor element.