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This paper deals principally with the diagnosis and correction of contamination effects in energy dispersive microanalysis of low atomic number thin films on silicon substrates. Carbon contamination can be treated as an additional surface layer with a thickness that varies with time. It is possible to apply an elementary correction X-ray spectra under identical operating conditions but with different acquisition times, then extrapolating the experimental data to the zero contamination case. Ice build-up on the crystal is a particularly insidious problem for windowless detectors, since it results in gradual modifications of the detector efficiency curve, most noticeably in the low energy regime. This can lead to errors in analysis unless appropriate corrective action is taken, either by physical removal of the ice layer or, for moderate icing, by allowing for the additional absorption effect in the quantification. It is shown that the assessment of the degree of detector icing by the commonly recommended method of determining the NiL/NiK alpha ratio is inadequate for analysis with very low energy X-rays, because the absorption of NiL in the ice layer is relatively weak compared to that of the emissions of practical interest.

Additional information

Authors: RICKERBY D, JRC Ispra (IT)
Bibliographic Reference: Paper presented: EMAS '95, St. Malo (FR), May 14-19, 1995
Availability: Available from (1) as Paper EN 38972 ORA
Record Number: 199510705 / Last updated on: 1995-07-07
Original language: en
Available languages: en