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

The functionality of the computer package AXIL (Analysis of X-ray spec tra by Iterative Least squares), suitable for the evaluation of energy -dispersive X-ray spectra, has been extended in a number of ways. Firs t, a background modelling algorithm, based on the use of mutually orth ogonal 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 backgro und contributions. Both innovations are shown to improve the performan ce of the spectrum evaluation procedure. Third, the user-friendliness of the evaluation program was enhanced (a) by allowing a PC plug-in MC A card to be directly controlled from within the program and (b) by ex tending the command-interface to allow for repeated execution of serie s 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.