The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to be used to evaluate specific aspects of the instrument performance of both X-ray and neutron powder diffractometers. This report describes SRM 640f, the seventh generation of this powder diffraction SRM, which is designed to be used primarily for calibrating powder diffractometers with respect to line position; it also can be used for the determination of the instrument profile function. It is certified with respect to the lattice parameter and consists of approximately 7.5 g of silicon powder prepared to minimize line broadening. A NIST-built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the Si powder. Both statistical and systematic uncertainties have been assigned to yield a certified value for the lattice parameter at 22.5 °C of a = 0.5431144 ± 0.000008 nm.

中文翻译：

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SRM 640f 粉末衍射线位和线形标准认证

美国国家标准与技术研究院 (NIST) 认证了一套标准参考材料 (SRM)，可用于评估 X 射线和中子粉末衍射仪的仪器性能的特定方面。本报告描述了 SRM 640f，这是该粉末衍射 SRM 的第七代，其设计主要用于校准粉末衍射仪的线位置；也可用于仪器轮廓函数的确定。它通过了晶格参数的认证，由大约 7.5 g 的硅粉组成，可最大限度地减少线展宽。NIST 制造的衍射仪结合了许多先进的设计特征，用于验证 Si 粉末的晶格参数。一种= 0.5431144 ± 0.000008 纳米。