Determination of the Void Volume in Silicon Single Crystals for Use in the Precision Measurement of Avogadro's Constant

硅单晶中空隙体积的测定用于精确测量阿伏伽德罗常数

• 批准号: 0084941
• 负责人: Frans Spaepen
• 金额: $ 33万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-01 至 2004-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0084941&HistoricalAwards=false
• 关键词: Determination; Void; Volume; Silicon; Single

This project is supported by NSF as a Cooperative Activity in Materials Sciences between the National Science Foundation and the European Commission. The kilogram is the only remaining fundamental unit that is still defined by a specific artifact: the standard kilogram, kept at the International Bureau of Weights and Measures in Paris. A more fundamental standard is needed and could be defined if Avogadro's number were known more accurately. An international consortium has been working for the last decade to determine Avogadro's number more accurately by measuring the physical properties of highly perfect silicon crystals. These studies, however, revealed a surprising occasional variation in the density of nominally equal quality float-zone silicon caused by the presence of small voids. This project aims to develop a method for determining the volume of these voids accurately through high-precision measurements of copper dissolved in silicon. The project is being carried out in collaboration with the Institute for Reference Materials of the European Commission, the National Institute of Standards and Technology, and the German Physikalisch-Technische Bundesanstalt.

该项目由NSF支持，作为国家科学基金会和欧盟委员会之间的材料科学合作活动。公斤是唯一剩下的基本单位，仍然由一个特定的人工制品定义：标准公斤，保存在巴黎的国际计量局。 需要一个更基本的标准，如果阿伏伽德罗数被更准确地知道，就可以定义这个标准。在过去的十年里，一个国际财团一直致力于通过测量高度完美的硅晶体的物理特性来更准确地确定阿伏伽德罗数。然而，这些研究揭示了由小空隙的存在引起的标称质量相等的浮区硅的密度的令人惊讶的偶然变化。 本项目旨在开发一种通过高精度测量溶解在硅中的铜来精确确定这些空隙体积的方法。 该项目是与欧洲联盟委员会参考材料研究所、国家标准和技术研究所以及德国联邦物理技术研究所合作开展的。