Experience on a cryogenic linear mechanism based on superconducting levitation

摘要

The instrumentation of many space missions requires operation in cryogenic temperatures. In all the cases, the use ofmechanisms in this environment is a matter of concern, especially when long lifetime is required.With the aim of removing lifetime concerns and to benefit from the cryogenic environment, a cryogenic contactlesslinear mechanism has been developed. It is based on the levitation of a permanent magnet over superconductor disks.The mechanism has been designed, built, and tested to assess the performances of such technology.The levitation system solves the mechanical contact problems due to cold-welding effects, material degradation byfatigue, wearing, backlash, lubrication...etc, at cryogenic temperatures. In fact, the lower is the temperature the better thesuperconductor levitation systems work.The mechanism provides a wide stroke (18mm) and high resolution motion (1μm), where position is controlled bychanging the magnetic field of its environment using electric-magnets.During the motion, the moving part of the mechanism levitates supported by the magnetic interaction with the hightemperature type II superconductors after reaching the superconductor state down to 90K.This paper describes the results of the complete levitation system development, including extensive cryogenic testing tomeasure optically the motion range, resolution, run-outs and rotations in order to characterize the levitation mechanismand to verify its performance in a cryogenic environment.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.