Gravimeter using high-temperature superconducting bearing

We have developed a sensitive gravimeter concept that uses an extremely low -friction bearing based on a permanent magnet (PM) levitated over a high-te mperature superconductor (HTS). A mass is attached to the PM by a cantileve red beam, and the combination of PM and HTS forms a bearing platform that h as low resistance to rotational motion but high resistance to horizontal, v ertical, or tilting motion. The combination acts as a low-loss torsional pe ndulum that can be operated in any orientation. Gravity acts on the cantile vered beam and attached mass, accelerating them. Variations in gravity can be detected by time-of-flight acceleration, or by a control coil or electro de that would keep the mass stationary. Calculation suggest that the HTS gr avimeter would be as sensitive as present-day superconducting gravimeters t hat must be cooled to liquid helium temperatures, but the HTS gravimeter ne eds cooling only to liquid nitrogen temperatures.