Design of a three‐detector system on LUOSHU: a small‐angle neutron scattering instrument at China Mianyang Research Reactor

The LUOSHU small‐angle neutron scattering instrument is one of the neutron scattering instruments under construction at the China Mianyang Research Reactor. Research interests in the fields of materials science, physics, chemistry and biology require that LUOSHU provide a wide range of measured scattering vector magnitudes (Q), a large dynamic Q range and high resolution. A movable and combined three‐detector system that consists of a high‐resolution position‐sensitive 3He multi‐tube rear detector and two L‐shaped front detectors is designed in order to expand the Q range and dynamic Q. Analytical calculations validate that, with the three‐detector system, LUOSHU can cover a Q range of four orders of magnitude. Also, the three‐detector system will extend the dynamic Q range and provide simultaneous Qmax/Qmin higher than 800 in operation, satisfying the requirements of in situ experiments. The LUOSHU small‐angle neutron scattering instrument is designed to provide a wide scattering vector magnitude (Q) range of four orders of magnitude by 46 m total length, for studies of nano‐particles ranging from the sub‐nanometre to the sub‐micrometre scale in numerous fields. A high dynamic Q range (Qmax/Qmin) is realized by a unique three‐detector system, for better efficiency in experiments. High‐flux and high‐resolution modes are ensured by two switchable velocity selectors, for more flexibility in different situations.