| Abstract Scope |
The development of theories for predicting radiation damage across multiple length and time scales plays a vital role in materials design for future fusion reactors. This is a scientific area with an urgent need for experimental data that can validate modelling assumptions. However, existing techniques for irradiation testing are constrained by temporal resolutions and cannot reach ultrafast time scales required to understand the atomic dynamics in radiation-damaged materials. To address this challenge, we have developed an approach capitalizing on the unique strength of ultrafast-electron diffraction (UED) technique to interrogate structural dynamics of fusion materials at the atomic time and length scales. Our approach has enabled a detailed examination of how W responds to extremely high temperatures when it contains point defects induced by high-energy heavy-ion irradiation. Using the time-resolved electron scattering technique, we directly observed the melting process in W with exceptional structural sensitivity capable of resolving displacement damage level below 0.01 dpa [1]. More recently, we delved into the phonon dynamics of W using an innovative technique known as ultrafast electron diffuse scattering [2]. This endeavor opens up new avenues for exploring material behavior with momentum-resolved information on interactions between phonons and electrons. Such precise experiments allowed us to benchmark Molecular Dynamics simulations of pure W and determine the most accurate potential model to describe heat transport and the microscopic motions of atoms and electrons.
[1] M. Mo et al. Science Adv. 5, eaaw0392 (2019).
[2] M. Mo et al. Science Adv. 10, eadk9051 (2024). |