The W‐1%La₂O₃ alloy has been irradiated by a single laser pulse (λ = 1064 nm) to simulate transient thermal loads of high energy occurring in a tokamak under operative conditions. A zone with a diameter of ~2 mm, namely, much larger than the focal spot, results to be affected by the pulse, and a crater of about 300 μm is observed in its center. La₂O₃ particles are not present inside the crater. The change of surface morphology is accompanied by elemental redistribution. Multipoint XPS analysis evidenced that the concentration of La is very low in the crater and increases moving toward the border of the affected zone while that of W shows an opposite trend. The composition changes involve only the outmost 5 nm of the sample: through depth profiling, no differences of chemical composition were detected deeper in the alloy between the center and external border of the affected area.

中文翻译：

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单个激光脉冲在W-1％La2O3的坑表面上的La分布

单个激光脉冲（λ= 1064 nm）照射了W-1％La ₂ O ₃合金，以模拟在工作条件下在托卡马克中发生的高能瞬态热负荷。直径约为2mm（即远大于焦点）的区域受脉冲影响，并且在其中心观察到约300μm的凹坑。La ₂ O ₃陨石坑内没有颗粒。表面形态的变化伴随着元素的重新分布。多点XPS分析表明，火山口中的La浓度很低，并向着受影响区域的边界移动，而W的浓度却呈现相反的趋势。成分变化仅涉及样品的最远5 nm：通过深度分析，在受影响区域的中心和外部边界之间的合金中未检测到更深的化学成分差异。