Redetermination of the Gravitational Constant using the BIPM Torsion Balance

For the past several years, we have been using the torsion balance developed at the Bureau International des Poids et Mesures (BIPM) to measure the gravitational constant G. The most notable feature of the apparatus is that it allows the measurement of G with two different methods: the Cavendish method and the Servo method.The systematic effects are different in several important variables, leading to an improved combined result. In the past year, we have identified a gas pressure effect that hampered previous measurements at the National Institute of Standards and Technology