Patent ID: 8065094

Claim:
A method, implemented in a processor, of calculating the structure of an inhomogeneous sample in which an electron beam is used to cause excitation of x-rays from the sample under known conditions of beam energy and geometry with respect to the sample, and wherein the beam current is unknown, the method comprising: i) obtaining measured x-ray intensity data for the sample, the data corresponding to one or more sets of beam conditions and beam currents, and inputting the measured x-ray intensity data into the processor; ii) obtaining comparative x-ray intensity data for samples having known structures and inputting the comparative x-ray intensity data into the processor; iii) estimating, in the processor, a beam current factor for each beam condition; iv) calculating, in the processor, effective x-ray intensity data for each of the sets of conditions using the measured and comparative x-ray intensity data and the beam current factor; v) calculating, in the processor, the structure of the sample for each of the sets of conditions using the effective x-ray intensity data; vi) predicting, in the processor, x-ray intensity data corresponding to the calculated structure; vii) comparing, in the processor, the predicted and effective x-ray intensity data; and viii) repeating steps (iii) to (vii) in the processor using beam current factors revised in accordance with step (vii) until the predicted and effective x-ray intensity data achieve a predetermined similarity criterion.