Lhermitte Julien R, Stein Aaron, Tian Cheng, Zhang Yugang, Wiegart Lutz, Fluerasu Andrei, Gang Oleg, Yager Kevin G
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, NY 11973, USA.
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, NY 11973, USA.
IUCrJ. 2017 Jul 10;4(Pt 5):604-613. doi: 10.1107/S2052252517008107. eCollection 2017 Sep 1.
Small-angle X-ray scattering (SAXS) often includes an unwanted background, which increases the required measurement time to resolve the sample structure. This is undesirable in all experiments, and may make measurement of dynamic or radiation-sensitive samples impossible. Here, we demonstrate a new technique, applicable when the scattering signal is background-dominated, which reduces the requisite exposure time. Our method consists of exploiting coherent interference between a sample with a designed strongly scattering 'amplifier'. A modified angular correlation function is used to extract the symmetry of the interference term; that is, the scattering arising from the interference between the amplifier and the sample. This enables reconstruction of the sample's symmetry, despite the sample scattering itself being well below the intensity of background scattering. Thus, coherent amplification is used to generate a strong scattering term (well above background), from which sample scattering is inferred. We validate this method using lithographically defined test samples.
小角X射线散射（SAXS）通常包含不需要的背景，这增加了解析样品结构所需的测量时间。这在所有实验中都是不可取的，并且可能使动态或辐射敏感样品的测量变得不可能。在这里，我们展示了一种新技术，适用于散射信号以背景为主的情况，它可以减少所需的曝光时间。我们的方法包括利用具有设计的强散射“放大器”的样品之间的相干干涉。使用修改后的角关联函数来提取干涉项的对称性；即，由放大器和样品之间的干涉产生的散射。这使得尽管样品散射本身远低于背景散射强度，仍能够重建样品的对称性。因此，相干放大用于生成一个强散射项（远高于背景），并据此推断样品散射。我们使用光刻定义的测试样品验证了该方法。
