A new instrument for the measurement of diameter and form of cylinders

摘要

A new instrument capable of measuring the diameter and form of cylinders up to 10 mm diameter with uncertainties at the +-10 nanometre level is being developed. The primary purpose of the instrument will be to characterize the geometry of pistons used in realizing high-pressure standards, but the instrument will have general applicability. The measurement of diameter is achieved by continuously and independently measuring the positions of two mutually opposed contact probes, using two sub-nanometric displacement measuring laser interferometers.