A new method for calibration-free analysis by Laser-Induced Breakdown Spectroscopy using a time-integrated spectrometer

In this paper, we will discuss a new method for obtaining information about the plasma temporal evolution in Laser-Induced Breakdown Spectroscopy (LIBS) experiments using a time-integrated spectrometer. The method, inspired to the Bredice 3D-Boltzmann plot formalism, allows a precise determination of the temporal evolution of the emission line intensity in a LIBS plasma, starting from a series of time-integrated measurements obtained at different delay times after the laser pulse. In this way the application of a calibration-free algorithm using a time-integrated spectrometer is made possible. Examples of the application of the method are given in the analysis of two Zamac (a zinc alloy containing aluminum, magnesium, and copper) certified samples. A good agreement is obtained between the calculated and nominal concentrations of the two samples. A further validation of the method was performed on a third Zamac sample, of unknown composition. The sample was first characterized using a conventional CF-LIBS approach on a time-resolved spectrum; the obtained composition was then compared with the one determined using the series of time-integrated spectra.