Compound Refractive Lenses for Thermal Neutron Applications

Refractive lenses can dramatically improve neutron instrumentation in DOE facilities. In previous experiments, compound refractive lenses (CRLs) were shown to be capable of imaging using thermal neutrons. However, a number of problems exist that prevent the full implementation of these lenses: the initial prototype lenses, which used compression molding of metals, have long focal lengths, small fields of view, poor surface quality, and material inhomogeneities. To achieve shorter focal lengths and shorter neutron wavelengths, the radii of curvature must be reduced. This project will use an injection-molding bubble injection process to design and fabricate refractive lenses that will be able to focus, collimate, and image thermal neutrons. Both simple concave and Fresnel lenses will be investigated. Commercial Applications and other Benefits as described by the awardee: The new CRLs should provide better resolution and higher quality images. They will be inexpensive, compact, and capable of imaging using thermal neutrons with wide bandwidth spectra. Since CRLs should have very modest cost, they would be much less expensive than the large mirrors and other optics currently used. Many scientific and technological applications should ensue, including microscopy, scattering, interferometry, crystallography, and reflectometry.