Detection of deuterium retention by LIBS at different background pressures

ITER plans foresee the quantitative diagnostics of fuel retention in reactor walls at near-atmospheric pressures. Using laser induced breakdown spectroscopy (LIBS) for this purpose assumes a reliable resolving of Balmer α-lines of hydrogen isotopes in spectra of plasma produced by focused laser radiation onto the target surface. To develop LIBS for quantitative diagnostics of fuel retention during the maintenance breaks of ITER, the effect of background gas pressure on the laser-induced plasma characteristics has been studied. The background pressure limits the expansion rate of plasma and as a result it leads to higher plasma concentrations. At the same time the limiting factor of the reso…