Comparison between an optical pressure standard based on multi-reflection interferometric technique and conventional primary standards

An optical pressure standard, based on a multi-reflection interferometric technique, has been recently developed. This quantum-based standard realizes the pascal through the measurement of the refractive index of a gas by an unbalanced homodyne interferometer and it is currently capable of measuring gas pressure with a relative uncertainty of 10 ppm at 100 kPa. The performance of such optical-based standard have been preliminary evaluated by comparing it with two conventional primary pressure standards, namely a force balanced piston gauge and a pressure balance, in the range from 400 Pa to 120 kPa. This work describes the performed study and discusses the results, which demonstrated the agreement between the optical pressure standard and the conventional standards in the considered range, within their related uncertainties (k = 1).