Abstract: A helium recovery plant adapted to filter, compress, and purify helium gas collected from one or more helium-using instruments, as well as to liquefy and redistribute the purified gas within a closed system. The recovery plant is adapted to match the purification and liquefaction rate of the system with the consumption rate of the coupled instruments. Additionally, the recovery plant is adapted to match the liquefaction rate of a liquefaction module with a boil-off rate of liquid helium within a Dewar thereof. The recovery plant is further adapted to recycle helium therein in an effort to achieve zero loss.

Abstract: Superconducting bearings inhibit the excitation of modes in a superconducting force measuring instrument such as a superconducting gravimeter, and effecively damp such modes in the event they are excited. Excitation of modes is inhibited by magnetically and/or physically blocking orbital and rotational motions. Modes which are excited are efficiently damped, preferably by inducing eddy currents in lossy metal parts. These dissipative eddy currents remove energy from the motion, causing the motion to decay exponentially with time. A significant advantage of the bearing design is that the magnetic field of the bearing can be isolated from the main levitation system. This ensures that the bearing interferes minimally with the gravity measurement.