Lauren Garrison

experiment to a single set of irradiation parameters (e.g., dose, fluence, injection rate, temperature etc.). Despite being capable of achieving damage rates up to three orders of magnitude higher than neutron irradiation, its overall sample throughput remains low due to the need to conduct separate irradiations for each unique parameter set. To address these limitations, a novel capability has been developed at the Michigan Ion Beam Laboratory (MIBL), enabling for the creation of two-dimensional lateral ion implantation gradients using recently installed motorized-controlled ion beam shutters. This advancement can generate a wide scope of the two dimensional (H+, He2+) implantation parameter space within a single sample. Integration of this new capability enables dual- and triple-ion beam experiments to be performed with full user control over not only the ion implantation depth profile, but also over the lateral imposed concentration gradients, thus providing researchers with a high-throughput means for material testing under various irradiation conditions. Furthermore, the recent installation of a microbeam in the ion-beam analysis (IBA) target station now allows for probing these concentration gradients in irradiated alloys with unprecedently high spatial resolutions. These developments promise to significantly improve ion irradiation capabilities, offering researchers a robust and high-throughput method to efficiently investigate candidate alloys for both advanced fission and fusion reactor applications, in both a time- and cost-effective manner. This paper demonstrates all the above through showcasing detailed implantation profiling and swelling characterization conducted over the lateral gradients imposed on single crystal Si and the fusion candidate alloy F82H-IEA.

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Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.