Characterization of the influence of the sample thickness upon the background in energy dispersive x-ray fluorescence (EDXRF)

The influence of sample thickness to the background region in energy dispersive x-ray fluorescence (EDXRF) system was investigated. The investigated spectrum was from 4.09 keV to 79.03 keV and was divided into 8 regions. Some of these regions include contributions by photons from tails of fluorescent lines. HgO samples with thicknesses from 0.010 to 0.335 cm were prepared. The samples were excited by 59.54 keV gamma rays from a 5 Ci Am-241 annular radioactive source in an energy dispersive x-ray fluorescence system. The scattered and emitted photons were counted by a high purity germanium (HPGe) detector. The results showed that the background intensity increases with the sample thickness and further enhancement in results in no further increase in the background intensity. The determined saturation (experimental) and critical (theoretical) thickness values considering the low and high energy tail regions of Compton scattering peak were compatible.