Precision Measurement of the Newtonian Gravitational Constant Using a Multi-Mode Apparatus

The Newtonian gravitational constant, G, has been experimentally obtained with the least precision when compared to all other fundamental constants. Currently, G is not linked by any complete theories to other forces of nature. The first experimental measurement was reported over 200 years ago and subsequent experiments performed across the globe have produced values that are incompatible with one another. After examining methodologies and associated erros reported in recent G experiments, a torsion pendulum apparatus was constructed at Indiana University Indianapolis in collaboration with California Polytechnic University Humboldt . This multi-mode apparatus contains the ability to perform G measurements using angular acceleration feedback and time of swing methods. This poster will give a status update regarding respective interferometric and temperature systems that will be used to characterize the experiment in accordance with the error buget. Preliminary estimates require an interferomtric position resolution of the experimental source masses to be 10 nanometers or better. The temperature inside of the 18 cubic meter thermal enclosure needs to remain constant within 5 milikelvin.