Détection en temps réel de nanoparticules par spectroscopie de plasma induit par laser

Christophe Dutouquet (1) , Tanguy Amodeo (1) , Olivier Le Bihan (1) , Emeric Frejafon (1)

1 INERIS - Institut National de l'Environnement Industriel et des Risques

Laser-Induced Breakdown Spectroscopy (LIBS) has been employed to detect sodium chloride and metallic particles with sizes ranging from 40 nm up to 1 μm produced by two different particle generators. The LIBS technique combined with a Scanning Mobility Particle Sizer (SMPS) was evaluated as a potential candidate for workplace surveillance in industries producing nanoparticle-based materials. Though research is still currently underway to secure nanoparticle production processes, the risk of accidental release is not to be neglected. Consequently, there is an urgent need for the manufacturers to have at their command a tool enabling leak detection in situ and in real time so as to protect workers from potential exposure. In this context, experiments dedicated to laser-induced plasma particle interaction were performed. To begin with, spectral images of the laser-induced plasma vaporizing particles were recorded to visualize the spatio-temporal evolution of the atomized matter and to infer the best confi guration for plasma light collection, taking into account our experimental set-up specifi city. Then, on this basis, time-resolved spectroscopic measurements were performed to make a fi rst assumption of the LIBS potentialities. The influence on the LIBS signal of parameters such as chemical nature of particles, their concentrations, laser wavelength, laser energy, kind of background gas was investigated and temporal optimization of the LIBS signal recording settings was achieved. Eventually, repeatability and limits of detection were assessed and discussed.

Les potentialités du système LIBS ont été évaluées en termes de détection de nanoparticules au voisinage des procédés de production. Pour optimiser l’enregistrement du signal LIBS des expériences d’imagerie ont été réalisées. Puis l’évolution temporelle du signal LIBS a été étudié en fonction de divers paramètres expérimentaux, tels que la nature du gaz ambiant, la longueur d’onde et l’énergie laser afin de mieux comprendre les mécanismes mis en jeux dans le plasma et d’optimiser les paramètres d’enregistrement temporels du signal. Suite à ces optimisations, les premières limites de détection du système LIBS ont été évaluées et comparées aux valeurs limites d’exposition des travailleurs.

Domaines: Sciences de l'environnement

Christophe Dutouquet, Tanguy Amodeo, Olivier Le Bihan, Emeric Frejafon. Détection en temps réel de nanoparticules par spectroscopie de plasma induit par laser. Rapport Scientifique INERIS, 2009, 2008-2009, pp.36-39. ⟨ineris-01869243⟩