Feltin Nicolas, Delvallée Alexandra, Crouzier Loïc
Laboratoire National de Métrologie et d'Essais (LNE), 29 Avenue Roger Hennequin, CEDEX, 78197 Trappes, France.
Nanomaterials (Basel). 2024 May 25;14(11):931. doi: 10.3390/nano14110931.
The concept of measurement traceability is crucial for ensuring the data reliability and the comparability of measurement results provided by different instruments and operators. In the field of nanoparticle metrology, determining the size of nanoparticles using electron microscopy-based techniques remains a real challenge. In laboratory settings, the establishment of traceability regarding the instrument calibration procedures, the assessment of uncertainties associated with instruments/operators/samples/environments, as well as the complexities related to electron-sample interactions, are often neglected. In this article, we describe the calibration procedure set up at the LNE (Laboratoire National de métrologie et d'Essais) and propose an evaluation method for determining the uncertainties in measuring nanoparticle size by SEM (Scanning Electron Microscopy). This study investigates the impact of the energy of the primary electrons (PEs) generated by the electron beam and accelerating voltage on the reliability of size measurements. The convolution between the signals coming from a nanoparticle and the substrate on which the particle is deposited induces edge effects that can have a negative impact on the measurement results. Finally, a diagram describing the various stages involved in establishing traceability for SEM measurements of nanoparticle size is proposed to facilitate the work of future operators.
测量可追溯性的概念对于确保数据可靠性以及不同仪器和操作人员提供的测量结果的可比性至关重要。在纳米颗粒计量领域，使用基于电子显微镜的技术确定纳米颗粒的尺寸仍然是一项真正的挑战。在实验室环境中，仪器校准程序的可追溯性建立、与仪器/操作人员/样品/环境相关的不确定度评估以及与电子-样品相互作用相关的复杂性，常常被忽视。在本文中，我们描述了法国国家计量与测试实验室（LNE）建立的校准程序，并提出了一种评估方法，用于确定通过扫描电子显微镜（SEM）测量纳米颗粒尺寸时的不确定度。本研究调查了电子束产生的一次电子（PEs）能量和加速电压对尺寸测量可靠性的影响。来自纳米颗粒的信号与颗粒所沉积的基底之间的卷积会产生边缘效应，这可能会对测量结果产生负面影响。最后，提出了一个描述纳米颗粒尺寸SEM测量可追溯性建立所涉及的各个阶段的示意图，以方便未来操作人员的工作。
