Neutron induced damage in future nuclear materials can be studied using heavy ion beams only if the differences in the microstructure evolution are well understood. Large variations in the damage dose rate, caused by scanning of the ion beam, can alter the microstructure compared to steady-state irradiation. We study the effect of scanning on the microstructure by irradiating pure iron with a 10 MeV Fe ion beam to a dose of 0.2 dpa. The beam is scanned in one direction with frequencies of 200 Hz and 10 kHz. Different shapes of the beam are also used to study the effect of dose variation. All of the irradiations are conducted at room temperature using the DiFU chamber at RBI. TEM analysis shows differences between the narrow beam and defocused irradiation modes, including unusual void formation observed at 10 kHz. A wider beam reduces the effect of scanning speed and no voids are found in this scanning case.

中文翻译：

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束扫描模式对离子辐照铁显微组织的影响

只有充分了解微观结构演化的差异，才能使用重离子束研究未来核材料中的中子引起的损伤。与稳态辐照相比，离子束扫描引起的损伤剂量率的巨大变化可以改变微观结构。我们通过用 10 MeV Fe 离子束以 0.2 dpa 的剂量照射纯铁来研究扫描对微观结构的影响。光束以 200 Hz 和 10 kHz 的频率沿一个方向扫描。不同形状的光束也用于研究剂量变化的影响。所有照射均使用 RBI 的 DiFU 室在室温下进行。TEM 分析显示了窄光束和散焦照射模式之间的差异，包括在 10 kHz 下观察到的不寻常的空隙形成。较宽的光束降低了扫描速度的影响，并且在此扫描情况下没有发现空隙。