Statistical considerations in microanalysis by energy-dispersive spectrometry

X-ray counting statistics plays a key role in establishing confidence limit s in composition determination by X-ray microanalysis. The process starts w ith measurements of intensity on one or more samples and standards as well as related background determinations. Since each individual measurement is subject to variability associated with counting statistics, it is necessary to combine all of the counting variability according to established mathem atical procedures. The next step is to apply propagation of error calculati ons to equations for quantitative analysis and determine confidence limits in reported composition. Similar concepts can also be applied to trace elem ent determination. This approach can then be combined with spectral simulat ion modeling, making it possible to predict detectability limits without ad ditional measurements.