Developments in Dynamic Analysis for quantitative PIXE true elemental imaging

Dynamic Analysis (DA) is a method for projecting quantitative major and tra ce element images from PIXE event data-streams (off-line or on-line) obtain ed using the Nuclear Microprobe. The method separates full elemental spectr al signatures to produce images that strongly reject artifacts due to overl apping elements, detector effects (such as escape peaks and tailing) and ba ckground. The images are also quantitative, stored in ppm-charge units, ena bling images to be directly interrogated for the concentrations of all elem ents in areas of the images. Recent advances in the method include the corr ection for changing X-ray yields due to varying sample compositions across the image area and the construction of statistical variance images. The res ulting accuracy of major element concentrations extracted directly from the se images is better than 3% relative as determined from comparisons with el ectron microprobe point analysis. These results are complemented by error e stimates derived from the variance images together with detection limits. T his paper provides an update of research on these issues, introduces new so ftware designed to make DA more accessible, and illustrates the application of the method to selected geological problems. (C) 2001 Elsevier Science B .V. All rights reserved.