Comparison measurements of low-pressure between a laser refractometer and ultrasonic manometer

• Published in: Review of scientific instruments Vol. 87; no. 5; p. 053113
• Main Authors: Egan, Patrick F, Stone, Jack A, Ricker, Jacob E, Hendricks, Jay H
• Format: Journal Article
• Language: English
• Published: United States 01.05.2016
• ISSN: 1089-7623
• DOI: 10.1063/1.4949504

We have developed a new low-pressure sensor which is based on the measurement of (nitrogen) gas refractivity inside a Fabry-Perot cavity. We compare pressure determinations via this laser refractometer to that of well-established ultrasonic manometers throughout the range 100 Pa to 180 000 Pa. The refractometer demonstrates 10(-6) ⋅ p reproducibility for p > 100 Pa, and this precision outperforms a manometer. We also claim the refractometer has an expanded uncertainty of U(pFP) = [(2.0 mPa)(2) + (8.8 × 10(-6) ⋅ p)(2)](1/2), as realized through the properties of nitrogen gas; we argue that a transfer of the pascal to p < 1 kPa using a laser refractometer is more accurate than the current primary realization.