美国国家标准与技术研究院(NIST)日前正式推出原子钟NIST-F2,与现有的NIST-F1标准一同作为新的美国民用时间与频率标准。NIST-F1自1999年以来一直作为标准,NIST-F2的准确度相当于3亿年不差一秒,是NIST-F1的3倍。据国际计量局(BIPM)数据,NIST-F2是目前世界上最精确的时间标准。两台钟使用铯原子“喷泉”确定1秒的精确长度。最近NIST科学家向BIPM报告了10年来处于研制阶段的NIST-F2首次正式发 The National Institute of Standards and Technology (NIST) recently introduced the atomic clock NIST-F2, along with the existing NIST-F1 standard as the new United States civil time and frequency standard. NIST-F1 has been the standard since 1999, and NIST-F2 has an accuracy of 300 million years, which is three times faster than NIST-F1. According to International Bureau of Metrology (BIPM) data, NIST-F2 is by far the most accurate time standard in the world. Two clocks use cesium atom “fountain” to determine the exact length of one second. Recently NIST scientists reported to BIPM for the first time in 10 years NIST-F2 under development