G Determination Measurement Using the Method of Free Fall

使用自由落体法测定 G 的测量

• 批准号: 9617498
• 负责人: James Faller
• 金额: $ 3万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-11-15 至 1997-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9617498&HistoricalAwards=false
• 关键词: Determination; Measurement; Using; Method; Free

The measurement of G, the Newtonian constant of Gravitation, is a long standing problem which continues to provide a challenge to our scientific creativity. Today's nearly 1% discrepancy between the recent PTB (Physikalisch-Technische Bundesanstalt) measurement and the `accepted` value of G is of considerable interest to experimental physics and the world of standards. The fact that the PTB measurement appears to be competently and thoughtfully done makes the discrepancy even more intriguing. A new free-fall approach (using g to measure G) will be used. In this experiment, an FG5 absolute gravimeter is to be employed in connection with a movable 1200 lb. Tungsten mass that surrounds the dropping chamber. Little g is measured when the surrounding mass is located above the FG5's dropping region and then when it is located below the dropping region. The 80 micro-gal difference in these two measurements together with the geometry of the surrounding mass can be used to determine G. A preliminary (proof-of- concept) experiment using a 200 lb. Mass has already been carried out. This follow-on experiment is expected to result in an accuracy for G of better than 5 parts in 10,000.

测量牛顿引力常数G是一个长期存在的问题，它继续对我们的科学创造力构成挑战。如今，最近的PTB （Physikalisch-Technische Bundesanstalt）测量结果与G的“可接受”值之间存在近1%的差异，这对实验物理学和标准界来说是相当有趣的。事实上，PTB的测量似乎是有能力和深思熟虑的，这使得这种差异更加有趣。将使用一种新的自由落体方法（用g来测量g）。在这个实验中，一个FG5绝对重力仪将被用于连接一个可移动的1200磅钨块，该钨块围绕着下落室。当周围质量位于FG5下降区域上方时测量小g，然后当它位于下降区域下方时测量小g。这两个测量值之间的80微加仑的差异，加上周围质量的几何形状，可以用来确定g。一个使用200磅质量的初步（概念验证）实验已经进行了。这个后续实验预计将导致G的精度优于万分之五。