Quantitative X‐ray microanalysis of thin foils in STEM

Abstract

A method, denoted MCAF, is described for the correction of x-ray intensities obtained during energydispersive analysis of alloy thin foils. The procedure is based on a Monte Carlo simulation of electron trajectories which defines the x-ray generation distribution, together with absorption and fluorescence corrections.Results ace presented for the analysis of three alloys: Nimonic C263, Type 304 stainless steel and a specifically cast and homogenised Ni-Al-Ti single-crystal alloy. The results indicate that the correction procedure works well at various foil thicknesses and take-off angles. The extent to which absorption of Mo in C263 and Al in the Ni-Al-Ti alloy and fluorescence in the stainless steel occurs is discussed. It is shown that fluorescence in thin foils, even of stainless steels, can be ignored below about 350 nm. Some comparison is made between the results predicted by MCAF and those obtained with a commercially available, thin foil correction procedure, RTM.