The relative intensity is one of the parameters of the spectral lines that indicate the emission strength of such lines. The spectral lines relative intensity database for most elements has been recorded a long time ago through spectroscopic data obtained by arc, spark, and vacuum tube. The problem is that relative line intensity is source dependent and the current database cannot be used for Laser-Induced Breakdown Spectroscopy (LIBS). Since LIBS is dealing with transient plasma, then a lot of parameters should be studied in order to find suitable conditions and a suitable way to record this database.
In this work, we are trying to find a way to construct a database for relative lines intensities that can be used properly in LIBS analysis. The LIBS spectral lines have been recorded for different delay times for different copper alloy samples. Then, some chosen copper' spectral lines were compared. An empirical formula has been proposed to calculate the spectral line intensity for each delay time. It was found that for delay times between 1000 ns and 2000 ns the spectral lines were related together in a way that the copper concentration doesn't affect the spectral line relative intensity but it only affects the value of the spectral line intensity.