Packing density effects on the fluctuations of the emission lines in laser-induced breakdown spectroscopy

In an earlier publication, we reported the results of a nanosecond-laser-induced breakdown spectroscopy (LIBS) analysis of pellets of Iron and Carbon and have shown that the shot-to-shot variations of the intensities of iron emission lines measured in iron to be much stronger than those measured in carbon. Here, we present a numerical model based on two-dimensional random close packing of disks in a confined geometry that shows that the fluctuation effects observed in C and Fe are essentially due to the packing density of the samples interrogated.