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

•Random packing density affects the intensity fluctuations of LIBS emission lines.•Excellent agreement between modeling and experiment using iron and carbon.•Approach may be explored for use of LIBS to determine the size of particles.

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.