Poster Spotlight: Accelerated Assessment of Primary Radiation Damage using High-Throughput Methods

Elena Botica Artalejo ^{1, 2} , Gregory M Wallace², Michael P. Short^{2, 3}

1. Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States.
2. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, United States.
3. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States. 

Elena Botica Artalejo ^{1, 2} , Gregory M Wallace², Michael P. Short^{2, 3}

1. Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States. 2. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, United States. 3. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States. 

In this project, we have developed a high-throughput approach using physical vapor deposition (PVD) to produce thick films with various compositions in a two-dimensional layout involving three different elements that form the alloy. Developing materials for plasma-facing components (PFCs) in fusion reactors is a difficult task, especially when additional functional requirements, such as electrical conductivity for radio-frequency (RF) antennas, need to be considered in addition to strength, heat tolerance, and radiation resistance. To complicate matters further, even trace amounts of certain elements (e.g. Nb) create an unacceptable amount of nuclear activation after neutron bombardment. Traditional approaches to determine suitable materials are time-consuming and involve numerous tests before and after irradiation to evaluate a limited number of alloy variations. However, our new approach allows us to simultaneously assess the evolution of properties in multiple compositions following consecutive radiation exposures, providing immediate insights.

To establish a baseline for the chemical composition, electrical properties, and thermo-elastic properties of the resulting thick film (measuring 3-4 µm), we employ rapid and non-destructive techniques such as electron dispersive spectroscopy (EDS), four-probe electrical resistivity measurement, and transition grating spectroscopy (TGS). Subsequently, we subject the sample to ion irradiation and reevaluate its properties to observe the relative changes created by the primary radiation damage. This iterative process is repeated until we reach the critical dose required for an RF antenna. By simultaneously evaluating hundreds of alloy compositions, our approach significantly accelerates the workflow compared to traditional methods, while maintaining the experimental reliability of radiation damage data. The extent of primary radiation damage is quantified by measuring the relative change in thermal conductivity using TGS, enabling us to correlate regions with better radiation damage resistance with their specific compositions. The decay of the TGS signal after irradiation directly corresponds to the presence of a greater number of vacancies in the microstructure. Additionally, we assess other properties relevant to an RF antenna, such as electrical resistivity at increasing radiation doses. Our study presents findings from the Cu-Cr-Nb and other Cu-Cr-X ternary systems, highlighting implications for the development of Nb-free Cu super-alloys in fusion environments.