Glavic Artur, Stahn Jochen
Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, Villigen PSI, Switzerland.
Rev Sci Instrum. 2018 Mar;89(3):035105. doi: 10.1063/1.5004658.
Structure and magnetism at surfaces and buried interfaces on the nanoscale can only be accessed by few techniques, one of which is grazing incidence neutron scattering. While the technique has its strongest limitation in a low signal and large background, due to the low scattering probability and need for high resolution, it can be expected that the high intensity of the European Spallation Source in Lund, Sweden, will make many more such studies possible, warranting a dedicated beamline for this technique. We present an instrument concept, Highly Extended K range And Tunable Experiment (HEKATE), for surface scattering that combines the advantages of two Selene neutron guides with unique capabilities of spatially separated distinct wavelength frames. With this combination, it is not only possible to measure large specular reflectometry ranges, even on free liquid surfaces, but also to use two independent incident beams with tunable sizes and resolutions that can be optimized for the specifics of the investigated samples. Further the instrument guide geometry is tuned for reduction of high energy particle background and only uses low to moderate supermirror coatings for high reliability and affordable cost.
纳米尺度下表面和埋藏界面的结构与磁性只能通过少数技术来研究，掠入射中子散射就是其中之一。尽管该技术因散射概率低且需要高分辨率而存在低信号和大背景这一最大局限，但可以预期，瑞典隆德的欧洲散裂中子源的高强度将使更多此类研究成为可能，因此需要为该技术建造一条专用束线。我们提出了一种用于表面散射的仪器概念，即高扩展K范围可调谐实验（HEKATE），它结合了两个Selene中子导管的优点以及空间分离的不同波长框架的独特功能。通过这种组合，不仅能够测量大的镜面反射范围，甚至在自由液体表面上也能测量，而且还能使用两束具有可调尺寸和分辨率的独立入射束，这些入射束可针对所研究样品的具体情况进行优化。此外，仪器导管的几何形状经过调整以减少高能粒子背景，并且仅使用低至中等的超镜涂层，以实现高可靠性和低成本。
