Demonstration of small-angle neutron scattering measurements with a nested neutron-focusing supermirror assembly

摘要

Neutron-focusing mirrors with both a nested structure and supermirror coatings enable a large collecting area, and consequently a large neutron current gain for mirror-based instruments. A nested neutron-focusing supermirror assembly has been fabricated with nested conical optics. Here, we demonstrate a series of small-angle neutron scattering (SANS) measurements using this supermirror assembly. A prototype instrument was built to measure the absolute scattering intensity of a solution of silica colloids, and the instrumental resolution was calibrated with highly ordered SBA-15. By comparing the theoretical and experimental values of the minimum Q (O_(min)), the non-geometrical component leading to the deterioration in Q_(min) is estimated and employed to calculate the performance of mirror-based SANS instruments. These results, together with the discussion on the capability of mirror-based instruments and other practical issues, are meaningful for promoting the development of neutron-focusing optics and mirror-based SANS instruments.