Non linear effects in TXRF spectroscopy. A procedure for the evaluation of the dead time

In this work we have studied the non-linear effects in TXRF spectroscopy, in the upper limit of linear response of the technique, when the analyzed specimen can not be considered as a thin film. In order to evaluate the Dead Time effects a mathematical methodology was developed, and an experimental sequence have been applied to spectra obtained from "ad-hoc" made samples. Specimens were obtained from samples affected by a preestablished serial dilution, so their spectra were acquired in conditions of high, medium and low counts. In these conditions, the nonlinear effects were sequentially evaluated as a function of the sample amount. For the simple inorganic samples studied here, with Dead Times values around 10%, this effect proved to be more important than the Matrix Effects. Since the non linear distortions produced by the Dead Time are unpredictable and irreversible, the amount of the analyzed specimen should be carefully evaluated before the measurements are made.