PIXE Analysis of Samples of Intermediate Thickness

A procedure for making accurate matrix corrections in PIXE analyses of samples of intermediate thickness has been developed. The transmission of a collimated X-ray beam through different parts of the sample is measured with a Si(Li) detector to determine the thickness and shape of the sample. Experiments have been performed using uniform polymer foils doped with known concentrations of different elements and with thicknesses ranging from 1.5 to 11 mg/cm2. The results from these samples indicate that the accuracy of the correction procedure is better than 5%. The correction procedure has been applied to, e.g., samples obtained in single orifice cascade impactors