Method of determining a given characteristic of a material sample

A method of determining a given characteristic of a material sample by X-ray analysis, which method comprises

• a) making X-ray measurements on the sample to obtain an experimental X-ray diffraction profile determined at least in part by the given characteristic,
• b) calculating an expected X-ray diffraction profile for the sample using selected parameters,
• c) applying a degree of smoothing to the experimental profile to reduce the structural features thereby producing a smoothed experimental profile,
• d) applying the same degree of smoothing to the calculated profile to produce a smoothed calculated profile.
• e) comparing the smoothed calculated profile with the smoothed experimental profile to determine the difference between the smoothed calculated profile and the smoothed experimental profile,
• f) modifying the calculated profile by varying at least one of the parameters until the smoothed modified calculated profile fits the smoothed experimental profile,
• g) repeating steps c) to f) using each time a degree of smoothing less than the previous time so that the structural features return and the final modified calculated profile provides a desired fit to the experimental profile thereby enabling the given characteristic to be determined from the parameters used for the final modified profile.