An inductive position sensor for the measurement of large displacements at low temperature

An inductive position sensor used to measure centimeter displacements with a typical sensitivity of 140 mV/m at 4.2 K is described. The sensor's outer housing is constructed of brass and stainless steel tubing, with two inset linear bearings that support a surface ground carbon steel drive rod. The sensitivity of the device increases with excitation frequency and with operating temperature. The displacement range for which the sensor output is linear is 1.4 cm. The resolution of the device is better than 12 mu m. The sensor is robust in design and in operation, and is insensitive to thermal cycling. (C) 1998 American Institute of Physics.