A Time-of-Flight Neutron Backscattering Spectrometer at the China Spallation Neutron Source: Principle, Design, and Its Prospects

The quasielastic neutron scattering technique is an indispensable tool for probing microscopic dynamics in condensed matter at the nanoscale. However, the lack of a high-resolution spectrometer has restricted comprehensive studies of dynamics in China. To address this gap, a new time-of-flight neutron backscattering spectrometer, NuBS, is currently under construction at the China Spallation Neutron Source. This review systematically introduces basic principles, instrumental design, and scientific opportunities of NuBS. NuBS is engineered to deliver high energy resolution with a broad dynamic range, based on the moderator pulse structure. Given the wide time window of NuBS, we highlight its research prospects in frontier areas, including energy storage materials and heterogeneous catalysis. NuBS is expected to provide new opportunities for studies of complex molecular dynamics and in situ investigations, significantly elevating the capabilities of the quasielastic neutron scattering community upon its scheduled completion.