Fabian Naab

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.

High moderation per unit volume solid moderator materials like yttrium hydride (YHx) are necessary for compact nuclear microreactors. However, the phase stability and hydrogen transport processes of YHx under high-temperature irradiation are largely unknown. Proton irradiation was conducted on YHx at 300 °C and 580 °C to 0.2 dpa using 1 MeV or 2 MeV protons in a high-vacuum environment. The hydrogen concentration was determined before and after irradiation using elastic recoil detection analysis, and microstructural evolution was examined via post-irradiation scanning transmission electron microscopy and Raman spectroscopy. Dislocation loops and cavities were observed in all conditions; their distribution was correlated with the bombarding proton energy and ion irradiation temperature. This work revealed that hydrogen retention is proportional to the formation of traps for hydrogen gas atoms and identified pathways for hydrogen release. The relative contributions of bulk or fast diffusion paths, such as grain boundaries, delamination boundaries, and stacking faults are discussed; the primary mechanisms of hydrogen loss are likely based on diffusion, ruling out artefacts of the experimental design. The study suggests proton irradiation may be a strong surrogate to study hydrogen transport in hydride moderator materials under irradiation.