Speaker
Description
I will summarize various atomistic computational efforts to understand materials science effects on the sensitivity of BeEST experiments. Quantum mechanical simulations based on density functional theory (DFT) were applied to understand possible uncertainties (broadening) of capture peak energies due to defects (impurities, clustering, intersitial vs substitutional doping, crystal damage, grain boundaries) in the host matrix (Ta vs Al) were evaluated. Molecular dynamics simulations based on an empirical potential, as well as a custom-crafted machine-learned interatomic potential trained to closely reproduce DFT, were applied to understand clustering of Li in Ta. Comparisons to experimental characterization with atom probe tomography and electron microscopy will be presented. The molecular dynamics simulations were also applied to help understand Doppler broadening of nuclear recoil spectroscopy performed during coincidence measurements with BeEST STJ array; the MD was used to model details of the nuclear stopping, as well as assess validity of analytical stopping power (ion slowing) models, used in the analysis.
