Laser induced plasma; Laser-ablation; Laser induced breakdown spectroscopy;INDUCED BREAKDOWN SPECTROSCOPY; ABLATION; DIAGNOSTICS; PICOSECOND; DEPOSITION; EMISSION; DYNAMICS; SURFACE; PULSES; SINGLE

A detailed theoretical and experimental analysis is performed for a wide range of laser operating conditions, typical for laser induced breakdown spectroscopy(LIBS) and laser ablation (LA) experiments on copper metallic target. The plasma parameters were experimentally estimated from the line intensities ratio which reflects the relative population of neutral excited species in the plasma. In the case of LA experiments the highest temperature observed was 8210 +/- 370 K. In case of LIBS measurements, a maximum temperature of 8123 K has been determined. The experimental results are in good agreement with a stationary, hydrodynamic model. We have theoretically investigated the plasma emission based on the generalized collisional-radiative model as implemented in the ADAS interconnected set of computer codes and data collections. The ionic population density distribution over the ground and excited states into the cooper plasma is graphically displayed as output from the code. The theoretical line intensity ratios are in good agreement with experimental values for the electron density and temperature range measured in our experiments. (C) 2017 Elsevier B.V. All rights reserved.

INDUCED BREAKDOWN SPECTROSCOPY; SPECTROCHEMICAL ANALYSIS; GEOLOGICAL SAMPLES; ROCKS; OPTIMIZATION; EMISSION; METALS; ORIGIN; PULSES; MARS

We present a study of the plasma generated by transversely excited atmospheric (TEA) CO2 laser irradiation of a basalt sample. The plasma was induced in air at atmospheric pressure. The same sample was also analyzed using a commercial LIBS system based on Nd:YAG laser and time-gated detection. The main plasma parameters, temperature, and electron number density were determined and analytical capabilities of the two systems compared. Despite differences in laser wavelength, pulse duration, applied fluence, and signal detection scheme, the two systems are comparable in terms of element detectability and limits of detection. In both cases, all elements usually present in geological samples were identified. The estimated limits of detection for most elements were below 100 ppm, while for Cu, Cr, and Sr they were around or below 10 ppm. The obtained results led to the conclusion that simple, cost- effective TEA CO2 LIBS system can find applications for geological explorations.