Designing the Next Generation of Materials for Rare-Event Searches: High-Strength, Ultra-Pure Copper Alloys

• Dimitra Spathara (University of Birmingham)

The quest to directly detect dark matter and unravel the nature of neutrinos has driven the development of experimental techniques with unprecedented sensitivity, placing extreme demands on detector-material-induced backgrounds. As a result, the choice of construction materials, particularly those in direct contact with the target medium, has become a critical limiting factor. Electroformed copper, thanks to its exceptional radiopurity, is the material of choice for low-background experiments. However, its limited mechanical strength and ductility restrict its application in large-scale, high-pressure, or load-bearing components. In this seminar, I will present a materials design perspective to address this challenge, focusing on recent advances in the synthesis and design optimisation of high-strength, radiopure copper-based alloys, specifically Cu-Cr and Cu-Cr-Ti, using computational thermodynamics. I will discuss how combining electrodeposition techniques with CALPHAD-based modelling enables rapid, predictive design of alloy compositions and thermal processing, allowing us to navigate the trade-offs between radiopurity, mechanical strength, and manufacturability. The physics impact of such materials breakthroughs will be illustrated through case studies of next-generation experiments.