Towards a better determination of big G

The Newtonian gravitational constant G is ill determined when compared to other universal constants due to its extremely weak interaction strength. Meanwhile, more questions are raised in the accuracy among the G measurements as results disagree with each other. To improve both the measurement accuracy and precision of G, a new apparatus based on the angular-acceleration-feedback torsion pendulum system was designed and assembled in IUPUI. The idea is to reveal potential unknown systematic errors by allowing three different methods (i) the time-of-swing method with large amplitudes, (ii) extracting the resonance frequency of the pendulum through noise measurements and (iii) the angular-acceleration feedback method to be carried out in the apparatus. A precision of 2 ppm is expected to be achieved by increasing the system size to reduce the error introduced by metrological uncertainties. System characterization data and preliminary results will be shown in the presentation.