Determination of hydrogen and deuterium in Zr-2.5Nb by laser ablation

Laser ablation is investigated as a microsampling technique for determining the content and spatial distribution of hydrogen and deuterium in zirconium alloys. Zr-2.5wt%Nb (Zr-2.5Nb) material is ablated under vacuum with the 1.06 μm output of a Nd:YAG laser. Elemental H and D in the ablation plume are detected in a time-of-flight mass spectrometer (TOF-MS) following photo-ionization via the 1s-2s two-photon resonance near 243 nm. The laser/surface interaction is shown to be characterized accurately by a simple thermal model and the subsequent ablation is consistent with volume evaporation from the melted alloy. Elemental compositions in the ablation plume are found to represent those in the alloy. The analytical capabilities of laser ablation sampling are studied and discussed using various Zr-2.5Nb samples with known deuterium concentration gradients and bulk deuterium content. (orig.)