Study of material migration in thermonuclear reactors by CF LIBS method - case of molybdenum

The aim of this work was to perform basic research leading to the simplification of the diagnostics of the inner walls of the ITER tokamak (mirrors, limiters, parts of walls with molybdenum substrate, etc.). Being able to select optically thin molybdenum lines and correctly determine the basic parameters of laser-induced plasma from them proved, that we can perform a quantitative analysis of the divertor under all measured conditions. The best conditions, where the examined spectra were distinguished well, were under argon flow and for plasma diagnostics, the most suitable gate delay was 750 - 2000 ns after laser pulse in the case of nanosecond laser and 200 ns after laser pulse in case of picosecond laser. Using the correct temperature determined from the Saha-Boltzmann graph for molybdenum and the Boltzmann graphs for its ionization stages, it is possible to determine the concentration of impurities and fuel trapped on the tokamak wall, as shown by measurements of molybdenum-titanium-zirconium alloy sample. (Author)