Development of a robust in-vacuo and in-situ plasma-material interface (PMI) diagnostic elucidating plasma boundary-core confinement performance

Nuclear fusion is one of humanity’s grand challenges offering a non-fossil fuel, green energy source that is inherently safe and clean. There is a critical knowledge gap in fusion energy development on how the plasma-material interface correlates to plasma performance. Driving this gap is a lack of robust, in-situ and in-process diagnostics that can measure how the composition and structure of plasma-facing surfaces evolve and how theses changes affect plasma performance. Many of the important mechanisms that influence plasma performance at the material interface occur at ultrashallow length scales on a surface. Many of the known surface science techniques cannot operate under the extreme conditions of a fusion reactor. In other examples, plasma processing systems designed to grow semiconductor devices also suffer from this lack of metrology of the surface composition evolution of the materials fabricated. There is therefore a critical need for robust, reliable plasma-material interactions (PMI) diagnostics that can provide shot-to-shot surface diagnosis in fusion devices to optimize surface conditioning and discharge treatment improving plasma performance and similarly in low-temperature plasma processing devices to optimize device performance. Statement of How this Problem or Situation is Being Addressed: The new proposed approach in this program will focus on enabling the ability to measure surface composition and morphology in-process while the plasma-facing surface is exposed to the plasma environment. This would enable for dynamic correlations with plasma performance and the plasma-material interface increased by a time resolution of two orders of magnitude! Commercial Applications and Other Benefits: The proposed program will therefore focus on developing a design for two different PMI diagnostic platforms: 1) for fusion device plasmas and 2) for plasma processing tools. Phase 2 will consist of reliability and performance testing to scale up the compact, low-cost PMI diagnostic platform and identify fusion and plasma-based devices to enable performance testing and further development Key Words: Sputtering, surface, in-situ metrology, ion scattering spectroscopy, direct recoil, x-rays, plasma Summary for Members of Congress: To understand how fusion plasmas or plasma processing environments impact the device wall material and vice versa, a robust and versatile plasma-material interaction (PMI) diagnostic is being designed by Energy Driven Technologies LLC to measure surface composition and structure during the process of modification.