G Determination Measurement Using the Method of Free Fall

牛顿引力常数G的测量是一个长期存在的问题，它继续为我们的科学创造力提供挑战。 最近PTB（Physikalisch-Technische Bundesanstalt）的测量结果与G的“公认”值之间存在近1%的差异，这引起了实验物理学和标准界的极大兴趣。 事实上，PTB的测量似乎是称职和深思熟虑的，使差异更加有趣。 将使用新的自由落体方法（使用g来测量G）。 在本实验中，FG 5绝对重力仪将与可移动的1200磅重力仪连接使用。钨质量包围下降室。 当周围质量位于FG 5的下落区域上方时，测量到小g，然后当它位于下落区域下方时。 这两个测量值的80微伽差与周围物质的几何形状一起可以用来确定G。 一个初步的（概念验证）实验，使用200磅。弥撒已经进行了。 这一后续实验预计将导致G的精度优于万分之五。

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.