SBIR-STTR Award

Neutron scattering facilities are a key resource aiding the diverse and growing revolution in nano-science and technology-An ongoing challenge for these facilities is providing sufficient neutron flux for an acceptable signal-to-noise ratio for ever more precise experiments-Presently much of the neutron flux is lost because of inefficiencies in the hundreds of meters beam guides and other optics- Reflecting and focusing neutrons requires optical surfaces that smooth to the level of atomic dimensions (»1 Å)-This level of smoothness is extremely difficult, time-consuming, costly, and often impossible to achieve using conventional mechanical polishing methods, particularly when smoothing the metallic substrates and the 3-demensionally curved surfaces that are most desired for this application- The goal of our project is to produce two advanced neutron optics for Oak Ridge National Laboratories’ neutron scattering facilities- The first optic will be immediately upstream of the experimental stations and will require a complex 3-dimensional curvature to focus the neutron beam in both dimensions to a small spot-size that will allow the use of smaller sample sizes and pressure cells- The second optic will be used near the spallation neutron target or the reactor core, where the flux of high-energy neutrons is greatest, to increase the lifetime of these optics and to allow greater shielding from the high-energy neutrons- This optic will use a novel substrate material such as stainless steel- American Physics and Technology will apply two innovative new surface nano-smoothing technologies based on using high-energy, focused beams of nano-scale cluster ions to bombard the surface for the critical final smoothing steps required to produce the desired 1 Å surface finish- In phase I will demonstrate the cluster ion beam technology and produce a preliminary design of the two optics and the method of manufacturing them-

Neutron scattering facilities are a key resource aiding the diverse and growing revolution in nano-science and technology. An ongoing challenge for these facilities is providing sufficient neutron flux for an acceptable signal-to-noise ratio for ever more precise experiments. Presently much of the neutron flux is lost because of inefficiencies in the hundreds of meters beam guides and other optics that are used to transport the neutron from the source to the experiments. Reflecting and focusing neutrons requires optical surfaces that are smooth to the level of atomic dimensions (?1 Å). This level of smoothness is extremely difficult, time- consuming, costly, and often impossible to achieve using conventional mechanical polishing methods, particularly when smoothing the metallic substrates and the 3-demensionally curved surfaces that are most desired for this application. The goal of our project is to apply new surface smoothing technologies to improve the performance of neutron optics. In phase l we investigated two innovative, new, surface nano-smoothing technologies based on using high- energy, focused beams of nanoscale cluster ions to bombard a surface for the critical final smoothing steps required to produce the desired atomically-smooth surface finish. As a demonstration we manufactured flat m=3 neutron supermirrors on glass substrates. These will be evaluated soon using neutron reflectometry. In phase ll we will investigate the smoothing capability of these technologies for novel metallic substrate materials and for curved surfaces, and then we will demonstrate their performance by producing an advanced neutron optic for Oak Ridge National Laboratories’ neutron scattering facilities. The planned optic can be used upstream of an experimental station to reduce the spot size of the neutron beam to accommodate the use of small samples and high-pressure cells. These innovative polishing methods will allow more capable, quicker to manufacture and less expensive neutron optics for use at the many neutron scattering centers that are now operating or are under construction worldwide.