Development of a Long-Period Torsion Balance for Tests of Einstein\u27s Equivalence Principle and a Search for Normal Mode Torsional Oscillations of the Earth
This thesis describes the development of a torsion balance experiment designed to test Einstein\u27s equivalence principle with unprecedented sensitivity, while also taking a novel approach to directly observe the normal mode torsional oscillations of the Earth. Accordingly, a model of the signal expected from a potential equivalence principle violation has been developed, as well as a multi-slit auto-collimating optical lever which possesses a resolution on the order of a nanoradian and a range of observation of 10 milliradians and is used to monitor the torsion balance. A torsion balance with a natural torsional frequency of ~104 Hz, signi_cantly below the frequency of the longest of the Earth\u27s normal modes, was designed, built, and operated in a remote laboratory at Washington University\u27s Tyson Research Center. More than 1800 hours of data was collected and used to evaluate the performance of this prototype instrument and characterize the conditions in the Tyson laboratory
