Osti Naresh C, Jalarvo Niina, Mamontov Eugene
Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Mater Horiz. 2024 Sep 30;11(19):4535-4572. doi: 10.1039/d4mh00690a.
Quasielastic neutron scattering (QENS) is an experimental technique that can measure parameters of mobility, such as diffusion jump rate and jump length, as well as localized relaxations of chemical species (molecules, ions, and segments) at atomic and nanometer length scales. Due to the high penetrative power of neutrons and their sensitivity to neutron scattering cross-section of chemical species, QENS can effectively probe mobility inside most bulk materials. This review focuses on QENS experiments performed using a neutron backscattering silicon spectrometer (BASIS) to explore the dynamics in various materials and understand their structure-property relationship. BASIS is a time-of-flight near-backscattering inverted geometry spectrometer with very high energy resolution (approximately 0.0035 meV of full width at half maximum), allowing measurements of dynamics on nano to picosecond timescales. The science areas studied with BASIS are diverse, with a focus on soft matter topics, including traditional biological and polymer science experiments, as well as measurements of fluids ranging from simple hydrocarbons and aqueous solutions to relatively complex room-temperature ionic liquids and deep-eutectic solvents, either in the bulk state or confined. Additionally, hydrogen confined in various materials is routinely measured on BASIS. Other topics successfully investigated at BASIS include quantum fluids, spin glasses, and magnetism. BASIS has been in the user program since 2007 at the Spallation Neutron Source of the Oak Ridge National Laboratory, an Office of Science User Facility supported by the U.S. Department of Energy. Over the past sixteen years, BASIS has contributed to various scientific disciplines, exploring the structure and dynamics of many chemical species and their fabrication for practical applications. A comprehensive review of BASIS contributions and capabilities would be an asset to the materials science community, providing insights into employing the neutron backscattering technique for advanced materials characterization.
准弹性中子散射（QENS）是一种实验技术，它可以在原子和纳米长度尺度上测量迁移率参数，如扩散跳跃率和跳跃长度，以及化学物种（分子、离子和链段）的局域弛豫。由于中子具有高穿透能力以及它们对化学物种的中子散射截面敏感，QENS能够有效地探测大多数块状材料内部的迁移率。本综述重点介绍使用中子背散射硅谱仪（BASIS）进行的QENS实验，以探索各种材料中的动力学并理解它们的结构 - 性能关系。BASIS是一种飞行时间近背散射倒置几何谱仪，具有非常高的能量分辨率（半高宽约为0.0035 meV），能够测量从纳秒到皮秒时间尺度上的动力学。用BASIS研究的科学领域多种多样，重点是软物质主题，包括传统的生物学和聚合物科学实验，以及对从简单碳氢化合物和水溶液到相对复杂的室温离子液体和深共熔溶剂等流体的测量，这些流体可以是块状状态或受限状态。此外，在BASIS上常规测量各种材料中受限的氢。在BASIS上成功研究的其他主题包括量子流体、自旋玻璃和磁性。自2007年以来，BASIS一直在橡树岭国家实验室的散裂中子源的用户计划中，橡树岭国家实验室是由美国能源部支持的科学用户设施办公室。在过去的十六年里，BASIS为各种科学学科做出了贡献，探索了许多化学物种的结构和动力学以及它们在实际应用中的制备。对BASIS的贡献和能力进行全面综述将对材料科学界有很大帮助，为采用中子背散射技术进行先进材料表征提供见解。
