Knowledge Bank

A hydrostatic pumped-oil bearing has been used to support the moving mirror of Michelson interferometer. A liner loudspeaker-type motor is used to drive the moving shaft. With a digital velocity servo system that uses the zero crossings of He-Ne fringes as reference, excellent speed accuracy has been achieved. The system has been tested in vacuum with a speed range from .12cm/sec to .03 cm/sec. The standard deviations of the time interval between He-Ne laser fringes are found to be .4% at .12 cm/sec and 1% at .03 cm/sec. The construction of the oil bearing and oil feeding system will be described.