  In this work we have studied the limitations of the TXRF spectroscopy in the
upper limit of validity of the technique, when the analyzed specimen ceases to
be a thin film. We have evaluated the non-linear effects in spectra obtained
from samples made ad-hoc, which were acquired in a pre-established sequence of
dilutions. So, the spectra were obtained in conditions of high, medium and low
counts, thus the nonlinear effects were sequentially evaluated, as a function
of the sample amount. According to the conclusions of this work, the Dead Time
should be avoided since its effects are unpredictable and irreversible once the
spectra are obtained.
