Hybrid Neutron Supermirrors

RMD proposed to address these challenges with a novel hybrid manufacturing technique that combines the precision of ALD and efficiency of PVD. This innovative approach leverages ALD's precision in growing the ultrathin features required for high reflectivity and PVD's capacity for depositing thicker layers at a fast rate for efficient manufacturing. During this phase I project, RMD found e-beam evaporation to be the preferred technique to be paired with ALD for hybrid neutron supermirror manufacturing. Based on this, RMD designed an advanced highuniformity-over-a-large-area e-beam evaporation system. Concurrently, RMD created a sophisticated simulation code for designing supermirrors, called SuperMirror Layer Engineering aka SMiLE. SMiLE is able to switch materials based on film thickness from ALD metal nitrides to PVD metals and is designed to break up supermirrors into smaller modules accounting for real-world changes such as in the interfacial roughness with film thickness. SMiLE designs neutron supermirrors with the minimal total thickness required reducing the time required to deposit for efficient manufacturing. With SMiLE, RMD has produced a mirror design with an average reflectivity of 65% based on applying the hybrid approach, a 1.2x improvement of the state-of-the-art mirrors produced by SwissNeutronics. Building on this success, Phase II will focus on the demonstration of a m=7 neutron supermirror designed by SMiLE and deposited via the hybrid method combining established ALD processes for the thinnest layers and the PVD method developed in this phase I project for the thicker layers. 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.