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

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2020-08, Vol.972, p.164072, Article 164072
• Main Authors: Wu, Huarui, Wang, Zhiyuan, Zhang, Yao, Mo, Wenbo, Bai, Pulin, Song, Kun, Zhang, Zhong, Wang, Zhanshan, Hussey, Daniel S., Liu, Yun, Wang, Zhe, Wang, Xuewu
• Format: Article
• Language: English
• Subjects: Neutron-focusing mirrors; SANS; Supermirror assembly
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2020.164072

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 (Qmin), the non-geometrical component leading to the deterioration in Qmin 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.