Mapping of hydrogen isotopes with a scanning nuclear microprobe

Elastic recoil detection analysis using heavy ions with a scanning nuclear microprobe was applied to determine the content of hydrogen isotopes in carbon material facing fusion plasma in the JET fusion reactor. The hydrogen and deuterium concentrations in re-deposited material were obtained by mapping a cross sectional cut of a wall sample. De-trapping and hydrogen release caused by the primary ion beam were investigated. For both the deuterium and hydrogen concentration a drop of ∼75% was observed from an extrapolated initial value to a final steady state region. A procedure was used to determine the initial concentration. In this way a mapping of the initial deuterium concentration could be obtained.