Null Test of the Gravitational Inverse Square Law and the Development of a Superconducting Six-Axis Accelerometer.

The goal of this research was to carry out an improved test of the inverse square law on a laboratory scale of 1 ~ 10 m, and to develop a sensitive cryogenic accelerometer to measure the three angular and the three linear accelerations at the same point in space time. The Laplacian of the Newtonian gravitational potential is source independent and is a null quantity in vacuum. This principle makes it possible to perform a null test of the inverse square law by using a three -axis gravity gradiometer as a null detector. A new three -axis superconducting gravity gradiometer has been completed in the course of this research. A prototype experiment using a single-axis gradiometer has previously been performed. The error analysis from this previous work has been generalized and expanded. Errors such as axis-misalignment, non-orthogonality of the instrument, common-mode misbalance, and the thermal sensitivity of the instrument are modeled in detail, and experimentally measured. Various source and detector orientations are suggested to minimize or eliminate these errors. (Abstract shortened with permission of author.).