A Design Of Weak Force Measuring Experiment Using Superconducting Technology

Superconducting levitation and superconductivity displacement sensing technology are used to measure weak force on the order of10-10N. By using a new designed test mass, the problems of using a large test mass in similar experiments can be overcame, and the signal is amplified to30times larger. Compared with the torsion pendulum, our design reduces gravitational multipole moments of test mass and as a result reduces the impact of time varying gravitational field around. By using a periodic annular source mass, disturbance of other sources is suppressed, the size of the source mass is reduced. Signal modulation is achieved using a inertial rotating source mass suspend by a superconducting lavation tub without servo control system, increases the measuring time that is limited by the size of source mass in other experiments, noise out of the measuring frequent band is suppressed. Errors caused by platform vibration and mismatch between test mass center and lavation tub center can be rejected by differential displacement sensing. Using the Earth’s rotation, we propose a new method to calibrate moment as weak as10-10Nm in a simple way that can be applied in the calibration of similar experiments. A series of new methods are used in the design of the experiment, we hope this thesis have some reference value to similar weak force measuring experiments.