Capacitive sensor for micropositioning in two dimensions

A compact sensor for measuring position in two dimensions has been developed. The device, operating on the principle that the capacitance of parallel plate electrodes depends on their mutual area of overlap, is compatible with high magnetic fields and cryogenic temperatures. A resolution of approximately 1.2 mu m has been achieved and is limited by the electronics used. The position reproducibility, which is limited by drift of the positioner used to test the sensor, has been measured to be better than 3 mu m. (C) 1998 American Institute of Physics.