Conformal Neutron Supermirrors by Atomic Layer Deposition

Neutron scattering techniques are essential for advancing research in areas such as energy storage, biomedicine, and quantum materials. However, current neutron optics are limited in their design and ability to efficiently focus and manipulate neutron beams, hindering the development of more advanced instruments. This project addresses the need for high-performance, 3D neutron focusing optics by developing conformal supermirror coatings using Atomic Layer Deposition (ALD). The overall objective of the combined Phase I and Phase II projects is to demonstrate the feasibility of ALD for fabricating neutron supermirrors on complex 3D geometries, overcoming the limitations of traditional fabrication methods like magnetron sputtering. In Phase I, the feasibility of depositing high-quality aperiodic multilayers using ALD was successfully demonstrated. Phase II focused on developing a novel Direct Liquid Injection ALD (DLI-ALD) system to enable faster deposition rates and the use of a wider range of materials. Alternative supermirror materials were explored, demonstrating excellent film quality and conformal coating capabilities. In Phase IIA, the project will focus on optimizing the DLI-ALD process for Ni/Ti-based supermirror deposition, fabricating these supermirrors on complex 3D optics designed in collaboration with researchers at MIT, and evaluating their performance in neutron scattering experiments at the MIT reactor and ORNL's Spallation Neutron Source. We will be aiming for fabricating mirrors with m-value>4. Presently there is no US-based commercial producer of supermirrors; the current suppliers are European small businesses. The success of this SBIR program will play a crucial path for establishing a domestic supplier that would be useful to U.S. neutron facilities in terms of price, quality, and supply. Apart from neutron optics, aperiodic multilayer coatings are also of interest for a variety of hard x-ray applications, including target diagnostics, astrophysics, high energy physics and free-electron lasers.