Standardless calibration for micro-XRF with capillary optics

CARLOS SOSA; JUAN JOSÉ LEANI; D. PEREZ; H.J. SÁNCHEZ

Villa Carlos Paz

Congreso; Latin-American Seminar of Analysis by X-Ray Techniques (SARX). 2014; 2014

FaMAF, Universidad Nacional de Cordoba

The XRF emission from a bulk sample has not a linear dependence with elementalof the so called matrix effects. The most versatile approach to correct matrix effects consists of theapplication of the Fundamental Parameter method (FP) which requires few calibration standards for thequantification of a wide range of matrices.For FP, the physical processes in the sample leading to the XRF emission are described by a set ofanalytical equations. It requires a database of fundamental parameters and the spectral distribution of theexcitation radiation as well. For the Microanalysis by XRF (microof the photon flux at the output of the focalization lens difficult a direct determination of the emergentspectrum. Different techniques have been used in the past to estimate the exindirect measurements, such as attenuation of the primary intensity [1], xray fluorescence in targets [3]. The first two methods are based on approximated theoretical models whichproduces limitations in accuracy.A recent induced XRF methodology consists of the measurement of the Kfrom several thin targets covering the emission energy interval of the xmean value theorem to obtain the traassuming an empirical energy dependence of the transmission function.In the present work this last methodology is expanded to obtain the excitation spectrum for micromeans of the employment of robust thick targets and avoiding assumptions on the physical characteristicsof the x-ray source. The proposed approach is described in detail and applied to characterize the xsource of our laboratory. Validation by means of quantitative anashown as well.