Principle and performance of a superconducting angular accelerometer

A sensitive angular accelerometer has been developed. The accelerometer contains a superconducting test mass suspended by a weak flexure pivot and has a bandwidth exceeding 10 Hz. A superconducting quantum interference device amplifier and superconducting circuit are used to detect angular displacement of the test mass. Three nearly identical units have been constructed and tested. An analysis of the instrument is presented along with experimental results. At 4.2 K, performance better than 3×10−9 rad s−2 Hz−1/2 has been demonstrated. The measured noise floor has been traced to seismic motion and temperature fluctuations. The thermal noise contributes less than 10−10 rad s−2 Hz−1/2. Application of the superconducting angular accelerometer to gravity gradiometry is discussed.