Sputter-deposition of ultra-thin film stacks from EUROFER97 and tungsten: characterisation and interaction with low-energy D and He ions

Abstract

We have sputter-deposited stacks of ultrathin layers from EUROFER97 and tungsten on silicon substrates. Ion beam analysis techniques are used for composition characterisation and microscopy methods are employed for structural examination. The films are subsequently studied by time-of-flight low-energy ion scattering (ToF-LEIS) for primary 10 keV He+ and 8 keV D+ ions to demonstrate an approach of providing accurate and precise experimental reference electronic stopping cross-sections for fusion-relevant steels. The energy-converted ToF-LEIS spectra are compared to Monte-Carlo simulations for quantitative analysis explicitly considering the influence of plural and multiple scattering. We discuss the deduced stopping cross-sections of EUROFER97 in comparison to predictions by SRIM using Bragg’s rule of stopping power additivity.

Focus on plasma-facing materials in nuclear fusion reactors

“…While the materials science community has a long history of conducting fundamental and applied research on plasma-materials interactions [6][7][8], this collection focuses on the same type of physics with respect to a nuclear fusion environment. The topics covered are unique to 'Plasma-Facing Materials in Nuclear Fusion Reactors' such as: deuterium and tritium retention in PFCs [9][10][11][12][13]; fundamental processes at the plasma-surface interface [10,[14][15][16][17][18][19][20]; evolution of structure and properties under fusion-reactor-relevant heat loads [21]; material degradation under ion exposure [15,16,19]; material degradation under neutron irradiation [9,21]; material erosion, migration, and deposition [14,15,18,20,22]; plasma fueling [12]; and diagnostics for plasmamaterials interactions [23]. Although the details of the underlying mechanisms that govern the above phenomena remain largely unresolved, the results presented here will drive the emergence of engineering solutions to the amelioration of plasma-facing materials degradation.…”