CF-LIBS quantification and depth profile analysis of Be coating mixed layers

A remote LIBS system is being considered as an analysis tool in ITER for monitoring the erosion and fuel retention in the first wall. This necessitates further investigation of the performance of LIBS for thick co-deposited layers consisting of ITER-relevant materials. The main goal of this work is determining the fuel content of the samples and D depth profile by LIBS and to compare the results with those obtained by other methods. The studied samples were Be-based mixed coatings on W substrates, containing D and in some cases C, O, or both. These impurities are relevant not only for ITER, but also for other fusion devices, such as JET-ILW. The laser ablation was performed at 10 mbar Ar pressure using a 5 ns pulse Nd:YAG laser at 1064 nm. Suitable Be and Ar spectral lines were employed for the evaluation of the electron temperature of the plasma using multi-elemental Saha-Boltzmann (MESB) plots. The electron density was obtained from the Stark broadening of the D_α and H_α spectral lines following deconvolution. The average elemental content of each coating was then obtained by calibration-free LIBS (CF-LIBS) and are in agreement with other techniques (TOF–ERDA, IBA).