Liu Chun-Ting, He Bo-Ching, Chen Guo-Dung, Chang Alice Chinghsuan, Wu Wen-Li, Fu Wei-En
Nano and Semiconductor Metrology Laboratory, Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 30011, Taiwan.
Nanomaterials (Basel). 2020 Aug 7;10(8):1549. doi: 10.3390/nano10081549.
The notion of an effective longitudinal coherence length with its value much greater than λ2/(2Δλ) has been adopted in small-angle X-ray scattering communities for years, where λ and Δλ denote the incident wavelength and its spread, respectively. Often the implications of the effective longitudinal coherence length do not even enter considerations in the designing and data treatment of small-angle scattering experiments. In this work, conventional transmission small-angle X-ray scattering (tSAXS) was performed to reveal a clear angular dependence on effective longitudinal coherence length. The measured values of effective longitudinal coherence length can be as high as one millimeter, whereas the value of calculated λ2/(2Δλ) is in nanometers.
多年来，小角X射线散射领域一直采用有效纵向相干长度的概念，其值远大于λ2/(2Δλ)，其中λ和Δλ分别表示入射波长及其展宽。在小角散射实验的设计和数据处理中，有效纵向相干长度的影响甚至常常未被纳入考虑。在这项工作中，进行了传统的透射小角X射线散射（tSAXS）实验，以揭示有效纵向相干长度明显的角度依赖性。有效纵向相干长度的测量值可高达一毫米，而计算得到的λ2/(2Δλ)的值则在纳米级别。
