We have investigated the applicability of Laser Induced Breakdown Spectroscopy (LIBS) for analyzing the changes in the composition and fuel retention of W and W-Ta coatings following exposure to D ₂ or mixed D ₂ -N ₂ plasma beams in the linear plasma device Magnum PSI. The exposed samples were characterized by in situ ns-LIBS and complementary analysis methods Secondary Ion Mass Spectroscopy, Energy Dispersive x-ray spectroscopy and Nuclear Reaction Analysis. In agreement with the used complementary analysis methods, LIBS revealed the formation of up to 400 nm thick co-deposited surface layer in the central region of the coatings which contained a higher concentration of the main plasma impurities, such as N, and metals, such as Ta and Mo, the latter originating mainly from the substrate and from the plasma source. The deuterium retention on the other hand was highest outside from the central region of the coatings.

Controlling plasma fuel retained in the plasma facing components of the first wall of a fusion reactor is one of the most important challenges influencing safe operation of the International Thermonuclear Experimental Reactor in the first place. This issue is proposed to be addressed by the laser-induced breakdown spectroscopy (LIBS) diagnostics, which is particularly powerful in studying the near-surface deposits and analyzing their composition. The main goal of the present study is determining the depth profiles of different elements in beryllium-based materials and the possible co-deposited layers that are formed on the walls of the Joint European Torus (JET) fusion device. Depth profiles estimated by LIBS are compared with those measured by secondary ion mass spectrometry, furthermore, the differences are discussed. In particular, the evolution of spectral lines of Be, as well as the main gaseous elements, such as Ne, N, O, and D, incorporated into the samples were extracted at different depths in the layers. LIBS diagnostics allowed making a fairly accurate analysis of the detected spectral lines of the elements on the samples. The effect of variations of the ablation rate and uncertainty that it introduces in LIBS measurements was also discussed. This investigation will have a significant impact on the development of pre-processing algorithms for machine learning models in terms of adaptation models operating on synthetic data for processing experimental spectra and is important from a point of view of LIBS tests being under preparation at JET.