ANALYSIS OF X-RAY-SPECTRA BY ITERATIVE LEAST-SQUARES (AXIL) - NEW DEVELOPMENTS

The functionality of the computer package AXIL (Analysis of X-ray spectra by Iterative Least squares), suitable for the evaluation of energy-dispersive X-ray spectra, has been extended in a number of ways. First, a background modelling algorithm, based on the use of mutually orthogonal polynomials was introduced to replace the linear or exponential polynomials employed previously. Second, the Gaussian photopeak model employed in previous versions of the program was extended to include the non-Gaussian parts of the characteristic peaks and related background contributions. Both innovations are shown to improve the performance of the spectrum evaluation procedure. Third, the user-friendliness of the evaluation program was enhanced (a) by allowing a PC plug-in MCA card to be directly controlled from within the program and (b) by extending the command-interface to allow for repeated execution of series of commands by means of control loops. A brief description of these changes is given; as an application, the accurate evaluation of micro-XRF images is discussed.