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Spurious contributions from scattered electrons in thin‐film X‐ray microanalysis
Author(s) -
LI Y. H.,
CHEN Z.,
LORETTO M. H.
Publication year - 1993
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.1365-2818.1993.tb03349.x
Subject(s) - bremsstrahlung , electron , microanalysis , acceleration voltage , materials science , optics , carbon fibers , substrate (aquarium) , thin film , spectral line , x ray , cathode ray , atomic physics , physics , chemistry , nuclear physics , nanotechnology , organic chemistry , astronomy , composite number , composite material , oceanography , geology
Summary Carbon films supported on half copper grids have been used in a JEOL 4000FX to investigate the source of Cu X‐rays generated when the electron probe is focused on the carbon film. Both horizontal and high take‐off angle detectors were used to collect the spectra with accelerating voltages at 200, 300 and 400 kV. Energy‐dispersive X‐ray results obtained with the electron beam focused either on the carbon film or to avoid the film have been compared. By tilting the copper grid along its cut edge, the contribution of X‐rays generated by electrons scattered by the sample has been distinguished from the contribution of specimen‐generated Bremsstrahlung. These observations, together with measurements made both with and without an objective aperture, show that the main spurious contribution is from the electrons, which interact with the lower objective pole‐piece, generating both backscattered electrons and high‐energy X‐rays which subsequently interact with the sample. This result is further confirmed by the observations on epitaxial CdTe and CdHgTe layers on a single‐crystal GaAs substrate.