Analysis of small angle scattering data by model fitting

摘要

Small angle scattering is a common technique for investigating fluctuations in materials, for sizes ranging from about ten to a few hundred Angstroms. The technique could be more widely used if data analysis were more convenient; however, expressions relating the small angle scattered intensity to materials parameters of interest tend to be complicated. Non-linear regression fitting of experimental small angle scattering data from metallurgical systems is discussed, and the analysis procedure is demonstrated for two models on data from a Ni-Si alloy undergoing phase separation. It is concluded that if sufficient information is available to permit the proper model to be identified, quantitative values for the relevant materials parameters can be extracted in a rather routine manner, provided the parameters are not too closely coupled.