Influence of temperature on period of torsion pendulum with a high-Q fused silica fiber

Due to the high-Q fused silica fiber’s extreme sensitivity to temperature change, the period estimation of torsion pendulum with high precision depends on the effective correction of the thermoelastic effect. In the measurement of G with the time-of-swing method, we analyze the complex relation between temperature and the pendulum’s period and propose a developed method to find the shear thermoelasticity coefficient as well as isolate the influence of temperature on period alone. The result shows that the shear thermoelasticity coefficient is 101(2) × 10−6/∘C, the resultant correction to Δ(ω2) is 9.16(0.18) ppm, and the relative uncertainty to G is less than 1 ppm.